Co-reporter:Xiao Bai, Shaoyu Lü, Haidi Liu, Zhen Cao, Piao Ning, Zengqiang Wang, Chunmei Gao, Boli Ni, Dongyang Ma, Mingzhu Liu
Carbohydrate Polymers 2017 Volume 175(Volume 175) pp:
Publication Date(Web):1 November 2017
DOI:10.1016/j.carbpol.2017.08.020
•A polysaccharides based injectable hydrogel scaffold was fabricated for bone repair.•The degradation of hydrogel is influenced by crosslinking methods and environment.•Bio-glass (BG) can be composited in the hydrogel for cranial bone repair.•The hydrogel has potential application as a bone tissue engineering scaffold.Bone disease is a public health problem around the word, and it is urgent to develop novel tissue engineering scaffolds for the complicated cranial bone regeneration. The present work developed a novel triple crosslinked polysaccharides based injectable hydrogel to composite bio-glass (BG) for cranial bone repair. Dynamic mechanical analysis showed the storage modulus (G′) of the hydrogel reached to ∼4000 Pa. While after compositing BG, G′ exceeded 4500 Pa. The degradation behavior of the hydrogel is influenced by hydrogel composition, crosslinking methods and degradation environment. Through compositing BG for rat cranial bone repair, excellent bone regeneration effect was achieved (chunks of “white” new tissue was detected in the defected site, HE histopathological analysis confirmed the new tissue was bone tissue). Thus, the hydrogel is suitable as the carrier of BG for bone repair, demonstrating the prepared triple crosslinked hydrogel is potential for bone tissue engineering applications.
Co-reporter:Lu Sun;Yang Zhou;Xufeng Zhou;Qiang Fu;Sijie Zhao;Xiaoyan Tu;Xiaolong Zhang;Liwei Ma;Hua Wei
Polymer Chemistry (2010-Present) 2017 vol. 8(Issue 3) pp:500-504
Publication Date(Web):2017/01/17
DOI:10.1039/C6PY02051H
An interesting thermo-regulated dual transition from unimers to vesicles, and finally to micelles, was reported for the first time, based on a toothbrush-like double hydrophilic block copolymer (DHBC), poly(N-isopropylacrylamide)-b-poly(oligo(ethylene glycol) monomethyl ether methacrylate) (P(NIPAAm)-b-P(OEGMA)), which was feasibly attributed to the presence of pendent oligo(ethylene glycol) (OEG) brushes and their entanglement with the stimuli-responsive block.
Co-reporter:Na Wen;Chunmei Gao;Shaoyu Lü;Xiubin Xu;Xiao Bai;Can Wu;Piao Ning;Shaofei Zhang
RSC Advances (2011-Present) 2017 vol. 7(Issue 73) pp:45978-45986
Publication Date(Web):2017/09/26
DOI:10.1039/C7RA08291F
The high pKa (8.26 to 8.6) of PBA has restricted its glucose-responsiveness in physiological conditions, and the high cytotoxicity of polymers is also a limiting problem in their potential application for insulin delivery. Novel amphiphilic glucose-sensitive dialdehyde starch polymers containing 3-aminophenylboronic acid (APBA) as a glucose-responsive group and mPEGylated dialdehyde starch (mPEG-DAS) with hydrophobic 7-hydroxycoumarin-4-acetic acid (Cou) were synthesized. This dialdehyde starch derivative can self-assemble into mPEG-DAS–APBA–Cou micelles with “shell–core” structures in phosphate-buffered saline solution (PBS). In addition, the drug-loaded micelles can release insulin rapidly in response to hyperglycemia in a physiological environment. The results demonstrated that the mPEG-DAS–APBA–Cou micelles showed notable glucose responsive behavior near the physiological range. The insulin release from the nanocarriers is sensitive to different concentrations of glucose, releasing insulin rapidly under the conditions of 3 mg mL−1 glucose while demonstrating comparatively inert release at 1 mg mL−1 glucose (pH 7.4). MTT assays and hemolysis studies both confirmed that the mPEG-DAS–APBA–Cou micelles have low cytotoxic activity to A549 cells and low blood toxicity. These results suggest that the glucose-sensitive dialdehyde starch micelles (mPEG-DAS–APBA–Cou) have potential applications as a glucose-responsive material for insulin delivery.
Co-reporter:Li Chang;Hongliang Liu;Yi Ding;Jiajing Zhang;Li Li;Xiqi Zhang;Lei Jiang
Nanoscale (2009-Present) 2017 vol. 9(Issue 18) pp:5822-5827
Publication Date(Web):2017/05/11
DOI:10.1039/C7NR00304H
Smart control of surface wettability by ionic liquids (ILs) is significant for designing IL-related intelligent materials and devices. Herein, we present mixed molecular brushes comprised of poly(phenylethyl methacrylate) and 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (PPhEtMA-co-PFDMS) grafted surfaces that are capable of dynamically regulating 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIm][NTf2]) wettability. 1H NMR and quartz crystal microbalance characterization demonstrate that the wettability changes result from a temperature-dominated cation–π interaction between [EMIm][NTf2] and PPhEtMA-co-PFDMS brushes.
Co-reporter:Xiao Bai, Shaoyu Lü, Zhen Cao, Boli Ni, Xin Wang, Piao Ning, Dongyang Ma, Hua Wei, Mingzhu Liu
Carbohydrate Polymers 2017 Volume 166(Volume 166) pp:
Publication Date(Web):15 June 2017
DOI:10.1016/j.carbpol.2017.02.062
•A physical and DA chemical dual-crosslinking injectable hydrogel was prepared.•A copolymer with much lower gelation concentration than F127 was synthesized.•The consecutively in vitro and in vivo DA click reaction is simple and efficiency.•The prepared hydrogel is suitable for bone tissue engineering application.In the present work, a thermosensetive copolymer with a low gelation concentration under 37 °C, F127@ChS (F127 crosslinked chondroitin sulfate) was synthesized via DA click chemistry between F127-AMI (maleimido terminated F127) and ChS-furan (furfurylamine grafted chondroitin sulfate). Then, dual crosslinked hydrogels were prepared based on F127@ChS and PEG-AMI (maleimido terminated polyethylene glycol). The physical crosslinking of F127@ChS affords the hydrogel fast gelation behavior, while in situ DA click reaction occurred between F127@ChS and PEG-AMI affords the hydrogel system covalent crosslinking. The dual crosslinked injectable hydrogel was applied as scaffold to load BMP-4 for rat cranial defect repair. As indicated by X-ray imaging, cranial digital images and histological (HE and Masson) staining analysis, new bone tissues were formed in the defected area after 12 weeks repair. The results demonstrate that the novel dual crosslinked injectable hydrogel offer an interesting option for cranial bone tissue engineering.
Co-reporter:Shaoyu Lü;Xiao Bai;Haidi Liu;Piao Ning;Zengqiang Wang;Chunmei Gao;Boli Ni
Journal of Materials Chemistry B 2017 vol. 5(Issue 20) pp:3739-3748
Publication Date(Web):2017/05/24
DOI:10.1039/C7TB00776K
Current hydrogels based on chondroitin sulfate (ChS) generally lack the necessary strength and precise mechanical tunability. Addressing these limitations, covalent cross-linking has evolved to produce hydrogels with desirable properties. However, such a methodology always precludes injection and self-healing. In this study, we employ DA click chemistry and dynamic acylhydrazone bond cross-linking for hydrogel formation that overcomes the limitations of current ChS hydrogels. Dynamic acylhydrazone bonds afford the hydrogel injectability and self-healing ability, while DA click chemistry facilitates the employment of covalent crosslinking for stabilization in vivo and modulating hydrogel properties in vivo. The study reveals that the obtained hydrogel possesses highly tunable viscoelastic and rheological properties, swelling and degradation behavior, and injectability and self-healing ability compared with ChS hydrogels cross-linked by single DA click chemistry or acylhydrazone bonds. Meanwhile, this hydrogel shows increased viability and reduced apoptosis of rat mesenchymal stem cells, and excellent tissue adhesive ability in vivo. The hydrogel was loaded with BMP-4 and used as a scaffold for rat cranial bone tissue engineering. The results demonstrated that new bone tissue was detected in the defected area of the cranial bone. Thus, this cytocompatible, injectable and self-healing hydrogel with tunable properties can be used as a scaffold for cranial bone tissue engineering and promote bone formation.
Co-reporter:Shao-Fei Zhang, Chunmei Gao, Shaoyu Lü, Jiujun He, Mingzhu Liu, Can Wu, Yijing Liu, Xinyu Zhang, Zhen Liu
Colloids and Surfaces B: Biointerfaces 2017 Volume 159(Volume 159) pp:
Publication Date(Web):1 November 2017
DOI:10.1016/j.colsurfb.2017.08.009
•Different generations polyglutamic acid peptide dendrimers were prepared.•A PEGylated polyglutamic acid peptide dendrimer based NK protection system was synthesized.•The NK loaded G3-PEG-G3 demonstrated the optimum enzyme activity.•The prepared G3-PEG-G3/NK (6/1) is suitable for dissolving thrombus in vitro.Nattokinase (NK) has been used as a new generation thrombolytic drug, due to its high safety, low cost and low side effects. However, it is sensitive to external environment and may lose the enzyme activity easily. Peptide dendrimer possesses functional groups on its surface, adjustable sizes, biodegradability, biocompatibility, and low toxicity, which could be used as ideal carrier for drug protection and delivery. Demonstrated for the first time in this paper, a PEGylated dendrimer (Gn-PEG-Gn) composed of polyglutamic acid is designed and synthesized as delivery platform of NK for thrombus treatment. A panel of PEGylated dendrimers with three different generations of 2, 3, 4 was prepared to investigate the effect of dendrimer architecture on the properties and therapeutic efficacy of the resultant NK-loaded delivery systems in terms of the morphology, dimension and enzyme activity. The results demonstrated that the NK-loaded G3-PEG-G3 (G3-PEG-G3/NK ratio of 6/1), of all the formulations, displayed the optimal enzyme activity for dissolving thrombus in vitro, thus offering great potential for the treatment of thrombus.Download high-res image (215KB)Download full-size image
Co-reporter:Haogang Duan, Shaoyu Lü, Hongyan Qin, Chunmei Gao, Xiao Bai, Yuhui Wei, Xin’an Wu, Mingzhu Liu, Xinyu Zhang, Zhen Liu
International Journal of Pharmaceutics 2017 Volume 516, Issues 1–2(Issue 1) pp:
Publication Date(Web):10 January 2017
DOI:10.1016/j.ijpharm.2016.11.036
The present study developed novel zinc ion cross-linked alginate/N-succinyl-chitosan (NSC) blend microspheres (MS) for co-delivery of zinc and 5-aminosalicylic acid (5-ASA) for synergistic therapy of colitis. Physicochemical characterization of blend MS was assessed using scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and energy dispersive X-ray spectrometer (EDS). In vitro release studies demonstrated that blend MS has a pH-dependent release property. Both 5-ASA and zinc have lower release in acid medium and higher release in colonic environment. The therapeutic efficacy of zinc cross-linked blend MS was evaluated using induced-colitis rat models, and showed a superior treatment effect in alleviating inflammation of colitis rats. No systemic toxicity was observed after oral administration of blend MS. Therefore, zinc ion cross-linked alginate/N-succinyl-chitosan blend MS appeared to be a good candidate for co-delivery of zinc and 5-ASA to colon, and had great potential application in inflammatory bowel diseases (IBD) treatment.Download high-res image (160KB)Download full-size image
Co-reporter:Chunmei Gao, Shaoyu Lü, Mingzhu Liu, Can Wu and Yun Xiong
Nanoscale 2016 vol. 8(Issue 2) pp:1140-1146
Publication Date(Web):30 Nov 2015
DOI:10.1039/C5NR06729D
The synthesis and properties of CO2 responsive and fluorescent dendritic polymers, poly(amido amine)/Pluronic F127 (PAMAM/F127), are reported in this paper. The morphologies and sizes of PAMAM/F127 dendritic polymers were investigated by dynamic light scattering (DLS) and transmission electron microscopy (TEM). PAMAM/F127 dendritic polymers showed unimolecular micelle morphologies at low concentrations, and changed to multimolecular micelles at higher concentrations. Additionally, fluorescence spectra and confocal laser scanning microscopy images showed that PAMAM/F127 dendritic polymers exhibited a fluorescent enhancement response to the presence of CO2. Apart from that, the release behavior of PAMAM/F127 gels under simulated body fluids was investigated by choosing curcumin as the hydrophobic drug. The results indicated that PAMAM/F127 dendritic polymers can be used to improve the solubility of curcumin, and the drug released faster in the presence of CO2. Such CO2 responsive fluorescent dendritic polymers are potentially applicable in cellular imaging or drug controlled release.
Co-reporter:Yang Wang, Chen Hou, Yun Zhang, Fu He, Mingzhu Liu and Xiaoli Li
Journal of Materials Chemistry A 2016 vol. 4(Issue 21) pp:3695-3702
Publication Date(Web):18 Apr 2016
DOI:10.1039/C6TB00276E
A novel amperometric biosensor for glucose detection was fabricated based on a mimetic multi-enzyme system by combing mimetic enzymes (metal–organic frameworks, MOFs) and glucose oxidase (GOx). The microcapsule constructed with polydopamine (PDA) and ZIF-8 using CaCO3 templates could be utilized not only to provide the biocompatible and non-toxic microenvironment to immobilize GOx, but also as an efficient mimetic enzyme because of the peroxidase-like properties of ZIF-8. The graphene nano-sheets (rGO) were bonded to the PDA/ZIF-8 microcapsules to accelerate the electron transfer between the microcapsule and the electrode, and the resulted PDA/ZIF-8@rGO showed excellent electro-catalytic activity towards H2O2. The mimetic multi-enzyme system was fabricated when GOx was immobilized in the as-prepared microcapsule, and the developed GOx/PDA/ZIF-8@rGO/GCE biosensor exhibited extraordinary electro-detection performance for glucose with two wide linear ranges from 1 μM to 1.2 mM and 1.2 mM to 3.6 mM, and the limit of detection was 0.333 μM (S/N = 3). Moreover, the good selectivity for glucose and satisfactory detection results in real samples of the prepared biosensor were also demonstrated.
Co-reporter:Xinggang Wang, Shaoyu Lü, Chunmei Gao, Chen Feng, Xiubin Xu, Xiao Bai, Nannan Gao, Jinlong Yang, Mingzhu Liu, and Lan Wu
ACS Sustainable Chemistry & Engineering 2016 Volume 4(Issue 4) pp:2068
Publication Date(Web):February 29, 2016
DOI:10.1021/acssuschemeng.5b01494
To minimize the negative impact of nitrogen and phosphorus pollution from wastewater and improve fertilizer use efficiency, a novel multifunctional slow-release compound fertilizer was prepared by recovery of NH4+ and H2PO4– from aqueous solutions onto amphoteric straw cellulose (ASC) adsorbent. The effects of adsorbent dosage, solution pH, contact time and ionic strength on adsorption were investigated. The adsorption quickly reached equilibrium. The maximum NH4+ adsorption capacity of ASC was 68.4 mg g–1 at around pH 7.0, whereas it was 38.6 mg g–1 for H2PO4– adsorption at pH 5.0. Moreover, the feasibility of reusing the nutrients-laden carrier material as a multifunctional slow-release compound fertilizer was determined. The study demonstrated the product with excellent slow-release and water-retention properties. Thus, it could improve soil moisture content and reduce soil moisture evaporation rate and was economical and environmentally friendly for application in horticulture and agriculture.Keywords: Adsorption; Amphoteric straw cellulose; Biomass; Multifunctional slow-release compound fertilizer; Wheat straw
Co-reporter:Can Wu, Jinlong Yang, Xiubin Xu, Chunmei Gao, Shaoyu Lü, Mingzhu Liu
European Polymer Journal 2016 Volume 83() pp:230-243
Publication Date(Web):October 2016
DOI:10.1016/j.eurpolymj.2016.08.018
•Novel redox-responsive core-crosslinked mPEG-St-DPA micelles were prepared.•mPEG-St-DPA micelles were stable, hemocompatible and biocompatible.•mPEG-St-DPA micelles exhibited high drug loading capacity after crosslinking.•mPEG-St-DPA micelles had a good redox-response for intracellular drug delivery.•mPEG-St-DPA micelles hold great potential as ideal drug delivery carriers.Novel redox-responsive core-cross-linked polymers were prepared by cross-linking mPEGylated starch (mPEG-St) with 3,3′-dithiodipropionic acid (DPA), a cross-linker containing a disulfide bond. The structure of the polymer based on starch (mPEG-St-DPA) was characterized using nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy. In addition, these polymers could self-assemble into micelles in phosphate-buffered saline (PBS) solution. The size and critical micelle concentration (CMC) of the mPEG-St-DPA micelles decreased with an increase in the degree of cross-linking. Interestingly, the size of the mPEG-St-DPA micelles increased gradually in the presence of 10 mM glutathione (GSH) owing to the cleavage of the disulfide bonds in the micellar core. The mPEG-St-DPA micelles showed good stability, exhibiting slight changes in size after 1000-fold dilution with PBS solution or 10-fold dilution with dimethyl formamide (DMF). The results of a protein adsorption test indicated that the mPEG-St-DPA micelles were hemocompatible. Doxorubicin (DOX), a model anticancer drug, was efficiently loaded into the mPEG-St-DPA micelles. The in vitro release studies revealed that the DOX-loaded mPEG-St-DPA micelles showed enhanced release of DOX in the presence of GSH. An in vitro MTT assay confirmed that the core-cross-linked mPEG-St-DPA micelles were biocompatible with HeLa cells, and the DOX-loaded mPEG-St-DPA micelles displayed higher inhibition of HeLa cell proliferation. These results suggest that the redox-responsive mPEG-St-DPA micelles hold great potential as ideal drug delivery carriers for cancer therapy.A core-crosslinked redox-responsive polymeric micelles based on mPEG-St crosslinked by DPA with disulfide bond (mPEG-St-DPA) were reported, which had excellent stability, biocompatibility and hemocompatibility. DOX was used as a model drug and efficiently loaded into mPEG-St-DPA micelles. And the release of the encapsulated DOX was accelerated in the presence of GSH due to the cleavage of the disulfide bonds.
Co-reporter:Mingjia Chen, Chunmei Gao, Shaoyu Lü, Yuanmou Chen and Mingzhu Liu
RSC Advances 2016 vol. 6(Issue 52) pp:46159-46169
Publication Date(Web):20 Apr 2016
DOI:10.1039/C6RA06585F
An ideal tumor drug delivery platform should offer little release of the drug in a physiological environment and fast release of the drug once endocytosis into the tumor tissues occurs. Therefore, we have developed a new kind of core-crosslinked copolymers (mPEG-St-SeSex) based on mPEGylated starch and diselenide bonds for rapid drug release. The corresponding core-crosslinked analogs mPEG-St-SSx and mPEG-St-CCx copolymers using 3,3′-dithiodipropionic acid and octanedioic acid as crosslinkers, respectively, were synthesized and used as controls. The results displayed that all amphiphilic core-crosslinked copolymers could form micelles with spherical structures in aqueous solution, showing advanced stability compared to non-crosslinked micelles (mPEG-St) in physiologically related and ultra micelle destabilization conditions. The disassembly of micelles triggered by DTT, combined with in vitro drug release assay and intracellular drug release studies using confocal laser scanning microscopy (CLSM), indicated that the DOX-loaded mPEG-St-SeSex micelles showed higher activity and could be more quickly disrupted than the DOX-loaded mPEG-St-SSx and mPEG-St-CCx micelles in reducing environment and subsequently rapidly released drug. These results, in addition to cell cytotoxicity studies, demonstrated that the mPEG-St-SeSex micelles have the potential to develop controlled drug-delivery systems for cancer therapy.
Co-reporter:Mingjia Chen, Chunmei Gao, Shaoyu Lü, Yuanmou Chen and Mingzhu Liu
RSC Advances 2016 vol. 6(Issue 11) pp:9164-9174
Publication Date(Web):15 Jan 2016
DOI:10.1039/C5RA23618E
At present, diselenide bonds have been considered as a novel dual redox-sensitive linkage. Nevertheless, few studies have focused on diselenide-linked polysaccharide as new biological materials. In this work, the diselenide-linked mPEGylated starch amphiphilic copolymers (mPEG-SeSe-St), which combined the biocompatibility of polysaccharide and the stimuli-responsiveness of diselenide linkages, were developed as a novel type of PEG-detachable drug vector for rapid drug release. The amphiphilic design of the mPEG-SeSe-St enabled the formation of self-assembled micelles with spherical core–shell structures in aqueous solution. The data of well-ordered appraisals demonstrated that mPEG-SeSe-St could be disrupted in the presence of a low concentration of hydrogen peroxide (H2O2, 0.1% (v/v)) or glutathione (GSH, 1 mM). The process of diselenide bonds' more rapid degradation than disulfide bonds led to a synergistically enhanced release of loaded anticancer drugs (DOX) in cellular environments. These results, combined with cell viability measurements and confocal laser scanning microscopy (CLSM), indicated that mPEG-SeSe-St micelles might have appeared as a refined platform for cancer therapy.
Co-reporter:Shaoyu Lü, Chen Feng, Chunmei Gao, Xinggang Wang, Xiubin Xu, Xiao Bai, Nannan Gao, and Mingzhu Liu
Journal of Agricultural and Food Chemistry 2016 Volume 64(Issue 24) pp:4965-4974
Publication Date(Web):May 31, 2016
DOI:10.1021/acs.jafc.6b01133
Fertilizer is one of the most important elements of modern agriculture. However, conventional fertilizer, when applied to crops, is vulnerable to losses through volatilization, leaching, nitrification, or other means. Such a loss limits crop yields and pollutes the environment. In an effort to enhance nutrient use efficiency and reduce environmental pollution, an environmental smart fertilizer was reported in the current study. Poly(aspartic acid) and a degradable macro-cross-linker based on l-aspartic acid were synthesized and introduced into the fertilizer as a superabsorbent to improve the fertilizer degradability and soil moisture-retention capacity. Sustained release behavior of the fertilizer was achieved in soil. Cumulative release of nitrogen and phosphorus was 79.8% and 64.4% after 30 days, respectively. The water-holding and water-retention capacities of soil with the superabsorbent are obviously higher than those of the control soil without superabsorbent. For the sample of 200 g of soil with 1.5 g of superabsorbent, the water-holding capacity is 81.8%, and the water-retention capacity remains 22.6% after 23 days. All of the current results in this study indicated that the as-prepared fertilizer has a promising application in sustainable modern agriculture.
Co-reporter:Xiao-Yan Tu;Ming-Zhu Liu;Hua Wei
Journal of Polymer Science Part A: Polymer Chemistry 2016 Volume 54( Issue 11) pp:1447-1458
Publication Date(Web):
DOI:10.1002/pola.28051
ABSTRACT
Polymer topologies exert a significant effect on its properties, and polymer nanostructures with advanced architectures, such as cyclic polymers, star-shaped polymers, and hyperbranched polymers, are a promising class of materials with advantages over conventional linear counterparts. Cyclic polymers, due to the lack of polymer chain ends, have displayed intriguing physical and chemical properties. Such uniqueness has drawn considerable attention over the past decade. The current review focuses on the recent progress in the design and development of cyclic polymer with an emphasis on its synthesis and bio-related properties and applications. Two primary synthetic strategies towards cyclic polymers, that is, ring-expansion polymerization and ring-closure reaction are summarized. The bioproperties and biomedical applications of cyclic polymers are then highlighted. In the end, the future directions of this rapidly developing research field are discussed. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 1447–1458
Co-reporter:Haogang Duan, Shaoyu Lü, Chunmei Gao, Xiao Bai, Hongyan Qin, Yuhui Wei, Xin’an Wu, Mingzhu Liu
Colloids and Surfaces B: Biointerfaces 2016 Volume 145() pp:510-519
Publication Date(Web):1 September 2016
DOI:10.1016/j.colsurfb.2016.05.038
•Mucoadhesive microparculates were prepared for colon target dual drug delivery.•In vitro and in vivo properties of microparticulates were evaluated in detail.•Microparculates has pH-sensitive release property and could release drug in colon.•This drug-delivery system show superior therapeutic efficiency for the colitis rats.In this work, thiolated chitosan/alginate composite microparticulates (CMPs) coated by Eudragit S-100 were developed for colon-specific delivery of 5-aminosalicylic acid (5-ASA) and curcumin (CUR), and the use of it as a multi drug delivery system for the treatment of colitis. The physicochemical properties of the CMPs were evaluated. In vitro release was performed in gradually pH-changing medium simulating the conditions of different parts of GIT, and the results showed that the Eudragit S-100 coating has a pH-sensitive release property, which can avoid drug being released at a pH lower than 7. An everted sac method was used to evaluate the mucoadhesion of CMPs. Ex vivo mucoadhesive tests showed CMPs have excellent mucosa adhesion for the colonic mucosa of rats. In vivo treatment effect of enteric microparticulates systems was evaluated in colitis rats. The results showed superior therapeutic efficiency of this drug delivery system for the colitis rats induced by TNBS. Therefore, the enteric microparticulates systems combined the properties of pH dependent delivery, mucoadhesive, and control release, and could be an available tool for the treatment of human inflammatory bowel disease.
Co-reporter:Chen Hou, Yang Wang, Qinghua Ding, Long Jiang, Ming Li, Weiwei Zhu, Duo Pan, Hao Zhu and Mingzhu Liu
Nanoscale 2015 vol. 7(Issue 44) pp:18770-18779
Publication Date(Web):12 Oct 2015
DOI:10.1039/C5NR04994F
This work reports a facile and easily-achieved approach for enzyme immobilization by embedding glucose oxidase (GOx) in magnetic zeolitic imidazolate framework 8 (mZIF-8) via a de novo approach. As a demonstration of the power of such materials, the resulting GOx embedded mZIF-8 (mZIF-8@GOx) was utilized as a colorimetric sensor for rapid detection of glucose. This method was constructed on the basis of metal–organic frameworks (MOFs), which possessed very fascinating peroxidase-like properties, and the cascade reaction for the visual detection of glucose was combined into one step through the mZIF-8@GOx based mimic multi-enzyme system. After characterization by electron microscopy, X-ray diffraction, nitrogen sorption, fourier transform infrared spectroscopy and vibrating sample magnetometry, the as-prepared mZIF-8@GOx was confirmed with the robust core–shell structure, the monodisperse nanoparticle had an average diameter of about 200 nm and displayed superparamagnetism with a saturation magnetization value of 40.5 emu g−1, it also exhibited a large surface area of 396.10 m2 g−1. As a peroxidase mimic, mZIF-8 was verified to be highly stable and of low cost, and showed a strong affinity towards H2O2. Meanwhile, the mZIF-8 embedded GOx also exhibited improved activity, stability and greatly enhanced selectivity in glucose detection. Moreover, the mZIF-8@GOx had excellent recyclability with high activity (88.7% residual activity after 12 times reuse).
Co-reporter:Shaoyu Lü, Chunmei Gao, Xiubin Xu, Xiao Bai, Haogang Duan, Nannan Gao, Chen Feng, Yun Xiong, and Mingzhu Liu
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 23) pp:13029
Publication Date(Web):May 28, 2015
DOI:10.1021/acsami.5b03143
With the fast development of cell therapy, there has been a shift toward the development of injectable hydrogels as cell carriers that can overcome current limitations in cell therapy. However, the hydrogels are prone to damage during use, inducing cell apoptosis. Therefore, this study was carried out to develop an injectable and self-healing hydrogel based on chondroitin sulfate multiple aldehyde (CSMA) and N-succinyl-chitosan (SC). By varying the CSMA to SC ratio, the hydrogel stiffness, water content, and kinetics of gelation could be controlled. Gelation readily occurred at physiological conditions, predominantly due to a Schiff base reaction between the aldehyde groups on CSMA and amino groups on SC. Meanwhile, because of the dynamic equilibrium of Schiff base linkage, the hydrogel was found to be self-healing. Cells encapsulated in the hydrogel remained viable and metabolically active. In addition, the hydrogel produced minimal inflammatory response when injected subcutaneously in a rat model and showed biodegradability in vivo. This work establishes an injectable and self-healing hydrogel derived from carbohydrates with potential applications as a cell carrier and in tissue engineering.Keywords: carbohydrate; cell encapsulation; dynamic mechanical analysis; injectable hydrogel; self-healing;
Co-reporter:Chen Feng, Shaoyu Lü, Chunmei Gao, Xinggang Wang, Xiubin Xu, Xiao Bai, Nannan Gao, Mingzhu Liu, and Lan Wu
ACS Sustainable Chemistry & Engineering 2015 Volume 3(Issue 12) pp:3157
Publication Date(Web):November 17, 2015
DOI:10.1021/acssuschemeng.5b01384
With the fast development of sustainable modern agriculture, there has been a shift toward the development of controlled/slow release fertilizers (CSRFs) that can overcome current limitations of conventional fertilizers. Ideally, CSRFs would release nutrient matching plants demands, even when environmental conditions fluctuate. However, no current CSRFs meet this ideal, especially as nutrient release is affected by temperature and pH. In this study, a “smart” fertilizer with polymer brushes of poly(N,N-dimethylaminoethyl methacrylate) grafting from polydopamine-coated ammonium zinc phosphate via surface-initiated atom-transfer radical polymerization is reported. The structure and morphology of the fertilizer were measured by transmission electron microscopy (TEM); the composition of the product was determined with Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and inductively coupled plasma (ICP) emission spectrometer. Dual-responsive controlled-release behaviors were characterized in water by spectrophotometry and ICP, and results demonstrate the “smart” fertilizer shows excellent temperature- and pH-responsive behavior to release nutrients according to the ambient environment. The nutrients release rate can be obviously accelerated in an acidic pH (below pKa) medium at a definite temperature. In addition, low temperature (below LCST) can accelerate the nutrients release rate in a basic medium (above pKa), which is contrasting to the reduction of nutrients release rate at high temperature (above LCST) in the same medium. The pH- and temperature-responsive “smart” fertilizer will improve nutrients availability and avoid excessive release of nutrients causing damage to plant roots at high temperature, which indicating that the stimuli-responsive system has potential application in sustainable modern agriculture.Keywords: Controlled-release fertilizer; Poly(N,N-dimethylaminoethyl methacrylate); Polydopamine; Surface-initiated atom-transfer radical polymerization; Temperature- and pH-response
Co-reporter:Yang Wang, Yun Zhang, Chen Hou and Mingzhu Liu
RSC Advances 2015 vol. 5(Issue 119) pp:98260-98268
Publication Date(Web):10 Nov 2015
DOI:10.1039/C5RA20996J
A novel hybrid nanocomposite of magnetic Fe3O4@ZIF-8 (zeolitic imidazolate framework-8 coated Fe3O4 nanocomposites denoted as Fe3O4@ZIF-8) decorated RGO (reduced graphite oxide) was prepared by a simple method for the first time and denoted as Fe3O4@ZIF-8/RGO. After the Fe3O4/RGO was formed by solvothermal approach, the MOFs (ZIF-8) was coated on the surface of Fe3O4 to get the Fe3O4@ZIF-8/RGO nanocomposite. The resulted Fe3O4@ZIF-8/RGO nanocomposite was characterized by means of the transmission electron microscope (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectra (FT-IR), X-ray diffraction spectrometry (XRD), X-ray photoelectron (XPS), and vibrating sample magnetometer (VSM). This nanocomposite was modified on the glassy carbon electrode to fabricate biosensor which used to electrochemical determination for dopamine (DA) in phosphate buffer solution. The results demonstrated the fabricated biosensor showed great potential applications in the detection of DA with remarkable enhanced effect on voltammetric response of DA. The linear relationship between the response peak currents and DA concentration was in range from 2.0 × 10−9 to 1.0 × 10−5 M, the limits of detection is 6.67 × 10−10 M. Moreover, the prepared biosensor also showed good selectivity for DA detection in the presence of ascorbic acid and uric acid and satisfactory result in real samples detection.
Co-reporter:Xinjie Zhang, Chunmei Gao, Shaoyu Lü, Haogang Duan, Nannan Jing, Di Dong, Caifeng Shi and Mingzhu Liu
Journal of Materials Chemistry A 2014 vol. 2(Issue 33) pp:5452-5460
Publication Date(Web):25 Jun 2014
DOI:10.1039/C4TB00905C
Optical glucose detection holds considerable promise for continuous in vivo glucose monitoring with wireless transdermal transmission and long-lasting activity. To construct a new class of optical glucose nanobiosensors with high sensitivity and selectivity at physiological conditions, the first generation of fluorescent poly(amido amine) (G1.0 PAMAM), serving as the optical code, was introduced into glucose-sensitive poly(N-isopropylacrylamide-(2-dimethylamino)ethyl methacrylate-3-acrylamidephenylboronic acid) copolymer microgels via a facile method. The fabricated microgels display the ability of adapting to the surrounding medium of different glucose concentrations over a clinically relevant range (0–20 mM) and convert biochemical signals into optical signals. As nanobiosensors, the G1.0 PAMAM functionalized microgels exhibit high selectivity for glucose over various kinds of potential primary interferents, such as lactate, human serum albumin and metal ions, in the physiologically important glucose concentration range. Compared to traditional fluorescent dyes and quantum dots, which are limited by photobleaching and toxicity, this microgel with remarkable anti-photobleaching property and low toxicity makes it possible to be used for long-term continuous glucose monitoring. Through in vivo investigations, it can be observed that G1.0 PAMAM functionalized microgels can achieve wireless transdermal detection, indicating that the fabricated microgels have potential applications as a new generation of nanobiosensors for the highly sensitive and minimally invasive continuous glucose monitoring.
Co-reporter:Chunmei Gao, Mingzhu Liu, Shaoyu Lü, Xinjie Zhang and Haogang Duan
Journal of Materials Chemistry A 2014 vol. 2(Issue 39) pp:6823-6829
Publication Date(Web):14 Aug 2014
DOI:10.1039/C4TB01186D
Supramolecular systems were constructed by the non-covalent coupling between PAMAM dendrimers with adamantyl groups and β-cyclodextrin graft PNIPAAm through host–guest interactions. Such supramolecular systems can further self-assemble into nanorods, which have thermoresponsive and excellent fluorescence properties. The injectable and percutaneous detection of fluorescent supramolecular systems will be of significant advantage in the future of biomedical monitoring.
Co-reporter:Jinlong Yang, Chunmei Gao, Shaoyu Lü, Xinggang Wang, Mingjia Chen and Mingzhu Liu
RSC Advances 2014 vol. 4(Issue 98) pp:55139-55149
Publication Date(Web):20 Oct 2014
DOI:10.1039/C4RA07315K
A novel amphiphilic polymer (mPEGylated starch-deoxycholic acid, mPEG-St-DCA) was successfully prepared by grafting hydrophobic deoxycholic acid (DCA) into mPEGylated starch. According to the characterization of 1H NMR and FTIR, mPEG-St-DCA polymers could self-assemble into micelles with spherical core–shell structures. With the degree of substitution (DS) of DCA increasing, the average size of micelles (pH 7.4) decreased to below 200 nm. Correspondingly, the critical micelle concentration (CMC) decreased from 0.048 to 0.022 mg mL−1. And zeta potential values were near −2 mV. But under the condition of pH 6.5, the size and CMC showed an increasing trend. Doxorubicin (DOX), a model anticancer drug, was efficiently loaded into mPEG-St-DCA micelles, and in vitro release exhibited that DOX-loaded micelles had a good in vitro pH-induced drug release. MTT assays confirmed that mPEG-St-DCA micelles were biocompatible with HeLa cells, and DOX-loaded micelles had a relatively better cytotoxicity against HeLa cells with a remarkably high IC50 of 5.74 μg mL−1. Confocal laser scanning microscopy (CLSM) analyses demonstrated that mPEG-St-DCA micelles could be internalized efficiently by HeLa cells to realize intracellular DOX release, which further enhanced the inhibition of cell proliferation. On the basis of the above results, it was indicated that novel amphiphilic mPEG-St-DCA micelles with pH-response could be used as drug delivery carriers for cancer therapy.
Co-reporter:Xinggang Wang, Shaoyu Lü, Chunmei Gao, Xiubin Xu, Yi Wei, Xiao Bai, Chen Feng, Nannan Gao, Mingzhu Liu and Lan Wu
RSC Advances 2014 vol. 4(Issue 35) pp:18382-18390
Publication Date(Web):08 Apr 2014
DOI:10.1039/C4RA00207E
In an effort to enhance the efficiency of fertilizer use and minimize adverse environmental effects, a novel biomass-based, multifunctional controlled-release fertilizer (BMCF) was prepared to improve nutrient use efficiency and enhance crop production systems for more sustainable agriculture practices. The fertilizer design included natural attapulgite as a matrix, co-granulated ammonium zinc phosphate and urea as fertilizer core, cellulose acetate butyrate (CAB) as an inner coating, and a carboxymethyl chitosan-g-poly(acrylic acid)/attapulgite (CMCS-g-PAA/APT) superabsorbent composite as an outer coating. The effect of an APT matrix, CAB inner coating and superabsorbent composite outer coating on nutrient release rate was investigated. The influence of the BMCF on water-holding and water-retention capacity of soil samples was determined. The degradation behavior of the CMCS-g-PAA/APT outer coating in soil solution was evaluated. The experimental results indicated that the product prepared by a simple and economical method can effectively reduce N leaching loss and runoff, improve soil moisture retention capacity, and ameliorate soil acidity and alkalinity.
Co-reporter:Jiucun Chen and Mingzhu Liu
RSC Advances 2014 vol. 4(Issue 19) pp:9684-9692
Publication Date(Web):28 Jan 2014
DOI:10.1039/C3RA47026A
Well-defined and nontoxic core–shell polymeric micelles, containing fluorescence units, were employed for efficient drug delivery of doxorubicin (DOX). The self-assembled structures were generated from triblock copolymers of poly(ε-caprolactone)-block-poly(glycidyl methacrylate)-block-poly(poly(ethylene glycol)methyl ether methacrylate) (PCL-b-PGMA-b-P(PEGMA)) with fluorescence units. Various experiments like structural characterization, fluorescence properties, cell viability studies, encapsulation studies, measuring cytotoxicity against fibroblasts and bladder cancer cells are performed on these polymeric micelles. All of these results demonstrate that these self-assembled micelles may be promising carriers for intravesical delivery of DOX for bladder cancer therapy.
Co-reporter:Shaoyu Lü, Chunmei Gao, Xinggang Wang, Xiubin Xu, Xiao Bai, Nannan Gao, Chen Feng, Yi Wei, Lan Wu and Mingzhu Liu
RSC Advances 2014 vol. 4(Issue 93) pp:51208-51214
Publication Date(Web):03 Oct 2014
DOI:10.1039/C4RA06006G
With the increasing public concern toward human health, environmental protection, and natural resource sustainability, there is a shift toward the development of environmentally friendly fertilizers based on biomass. In this study, a coated fertilizer system based on starch acetate (SA) and weakly cross-linked carboxymethyl starch/xanthan gum (CMS/XG) was developed to improve biomass utilization efficiency and reduce environmental pollution. The coated fertilizer with a diameter in the range of 2.5–3.0 mm possesses low moisture content and high mechanical hardness. Nutrient nitrogen reached a steady state of releasing equilibrium within 20 days and the release behaviour depended on the coating thickness and the plasticizer content of the SA film. Soil water-holding capacity determination showed that soil/coated fertilizer mixtures retained more water than the control soil, and the water content increased with increasing amount of the coated fertilizer in the soil. The experimental data indicated that the products based on starch derivatives as coating materials have preferable slow-release performance and the introduction of the natural polymers can improve biomass utilization efficiency, reduce nutrient loss and improve water use efficiency.
Co-reporter:Chuanming Yu, Chunmei Gao, Shaoyu Lü, Chen Chen, Jinlong Yang, Xin Di, Mingzhu Liu
Colloids and Surfaces B: Biointerfaces 2014 Volume 115() pp:331-339
Publication Date(Web):1 March 2014
DOI:10.1016/j.colsurfb.2013.12.023
•Novel pH-responsive micelles were prepared by a facile and green method.•The micelles are supposed to target cancer cells via sugar receptors for CS.•The micelles undergo disassembly and rearrangement under acid-stimulation.•The micelles can work as on–off switching drug devices for cancer therapy.Stimuli-responsive materials, enabling drugs to be released in the acidic tumor and intracellular microenvironments, draw an increasing attention in chemotherapy. Here novel pH-sensitive biodegradable micelles are fabricated using a one-step, one-medium process without organic solvent for efficient loading and rapid intracellular release of hydrophobic cargos. The amphiphilic chondroitin sulfate-histamine conjugate (CS-his) were successfully synthesized and assembled into nanoparticles in aqueous medium with desirable size (133 nm) and low critical micelle concentration (CMC) (0.05 mg/L). Owning to the pH-sensitive structure of imidazole, the nanoparticles show pH-responsive behavior upon reducing the pH value of surrounding media, accompany with formation of large aggregates and increase of ζ potential. When the nanoparticles were utilized to deliver the model drug DOX, they exhibited a specific on–off switch drug release behavior, triggering DOX release in acidic surroundings (intracellular endosomes) and sealing DOX in neutral surroundings (blood circulation or extracellular matrix). CCK-8 assays and confocal laser scanning microscopy (CLSM) against HepG2 cells indicated that the nanoparticles themselves had no associated cytotoxicity, while drug-loaded nanoparticles possessed high cytotoxicity to model cells and presented high efficiency of cellular uptake. These flexible micelles with an on–off switched drug release may offer a promising pattern to accurately deliver a wide variety of hydrophobic payloads to tumor cells for cancer therapy.
Co-reporter:Jinlong Yang, Yinjuan Huang, Chunmei Gao, Mingzhu Liu, Xinjie Zhang
Colloids and Surfaces B: Biointerfaces 2014 Volume 115() pp:368-376
Publication Date(Web):1 March 2014
DOI:10.1016/j.colsurfb.2013.12.007
•N,N-Bisacryloylcystamine crosslinker was used to prepare starch nanoparticles.•A novel type of reduction-sensitive starch nanoparticles was prepared.•Effect of process parameters on the size of starch nanoparticles was evaluated.•Starch nanoparticles were non-cytotoxic, biocompatible and biodegradable.•Starch nanoparticles exhibited a promising application prospect for drug delivery.A novel type of reduction-sensitive starch nanoparticles was prepared via the reversed-phase microemulsion method by using crosslinker, N,N-bisacryloylcystamine (BAC) with the disulfide linkages, which was specifically cleaved by dithiothreitol (DTT). Starch nanoparticles had a spherical morphology with a small size of 40 nm in the optimal condition. The influences of process parameters (starch amount, surfactant amount and oil/water (O/W) ratio) on the size of starch nanoparticles were studied by dynamic light scattering (DLS). BAC crosslinked starch nanoparticles were degraded into oligomers with the reducing agent of DTT due to the cleavage of the disulfide linkages. A model drug 5-aminosalicylic acid (5-ASA) could be loaded efficiently into starch nanoparticles and the in vitro drug release behaviors were also studied. The results suggested that the disulfide crosslinked starch nanoparticles exhibited an accelerated drug release behavior in the presence of DTT. In vitro methyl thiazolyl tetrazolium (MTT) assays indicated that BAC crosslinked starch nanoparticles had a good biocompatibility when cocultured with human HeLa cancer cells. Hence, with excellent biocompatibility and biodegradability, and rapid drug release in response to DTT, BAC crosslinked starch nanoparticles showed a great potential as a biomaterial carrier for the application of drug controlled release. In contrast to BAC crosslinked starch nanoparticles, N,N-methylenebisacrylamine (MBA) crosslinked starch nanoparticles were prepared as the control without the disulfide linkages.
Co-reporter:Xinjie Zhang, Shaoyu Lü, Chunmei Gao, Chen Chen, Xuan Zhang and Mingzhu Liu
Nanoscale 2013 vol. 5(Issue 14) pp:6498-6506
Publication Date(Web):07 May 2013
DOI:10.1039/C3NR00835E
The response to glucose, pH and temperature, high drug loading capacity, self-regulated drug delivery and degradation in vivo are simultaneously probable by applying a multifunctional microgel under a rational design in a colloid chemistry method. Such multifunctional microgels are fabricated with N-isopropylacrylamide (NIPAAm), (2-dimethylamino)ethyl methacrylate (DMAEMA) and 3-acrylamidephenylboronic acid (AAPBA) through a precipitation emulsion method and cross-linked by reductive degradable N,N′-bis(arcyloyl)cystamine (BAC). This novel kind of microgel with a narrow size distribution (∼250 nm) is suitable for diabetes because it can adapt to the surrounding medium of different glucose concentrations over a clinically relevant range (0–20 mM), control the release of preloaded insulin and is highly stable under physiological conditions (pH 7.4, 0.15 M NaCl, 37 °C). When synthesized multifunctional microgels regulate drug delivery, they gradually degrade as time passes and, as a result, show enhanced biocompatibility. This exhibits a new proof-of-concept for diabetes treatment that takes advantage of the properties of each building block from a multifunctional micro-object. These highly stable and versatile multifunctional microgels have the potential to be used for self-regulated therapy and monitoring of the response to treatment, or even simultaneous diagnosis as nanobiosensors.
Co-reporter:Chen Chen, Mingzhu Liu, Chunmei Gao, Shaoyu Lü, Jiucun Chen, Xiyong Yu, Enyong Ding, Chuanming Yu, Jing Guo, Guijia Cui
Carbohydrate Polymers 2013 Volume 92(Issue 1) pp:621-628
Publication Date(Web):30 January 2013
DOI:10.1016/j.carbpol.2012.09.014
Comb-shaped copolymers comprised of hydrophobic and hydrophilic blocks are self-assembled in aqueous solution, which results that they are suitable for delivery of hydrophobic drug molecules. Chitosan (CS) is an important biomaterial used widely in medical applications. Herein, a comb-shaped cationic copolymer composed of long biocompatible CS main chains and short PNIPAAm side chains was prepared via atom transfer radical polymerization (ATRP) by attaching an ATRP initiating group to N-phthaloyl chitosan. By subsequent removal of the protective groups on N-phthaloyl chitosan-graft-poly(N-isopropylacrylamide) (PHCS-g-PNIPAAm) copolymer with N2H4·H2O lead to the polymer pendant amino groups, this study attempted to synthesize a pH/temperature multi-responsive material. This chitosan-graft-poly(N-isopropylacrylamide) (CS-g-PNIPAAm) copolymer is self-assembled in aqueous solution into stimuli-responsive core–shell micelles with hydrodynamic diameters of about 170 nm. Structural organization and solution behavior were then investigated utilizing 1H NMR spectroscopy, transmission electron microscopy (TEM) and dynamic light scattering (DLS).Highlights► Comb-shaped CS-g-PNIPAAm copolymer was synthesized via ATRP. ► The grafting reaction occurred on the primary hydroxyl group. ► This multi-responsive copolymer is self-assemble in aqueous solution.
Co-reporter:Yinjuan Huang, Shenglong Ding, Mingzhu Liu, Chunmei Gao, Jinlong Yang, Xinjie Zhang, Bin Ding
Carbohydrate Polymers 2013 Volume 96(Issue 2) pp:426-434
Publication Date(Web):25 July 2013
DOI:10.1016/j.carbpol.2013.04.013
•The ultra-small and anionic starch nanospheres were prepared.•Effects of various preparation conditions were studied.•The starch nanospheres were non-toxic, biocompatible and biodegradable.•The starch nanospheres possess negative charge.•The particles exhibit a potential application in thrombolytic therapy.This paper is considered as the first report on the investigation of nattokinase (NK) release from anionic starch nanospheres. The ultra-small and anionic starch nanospheres were prepared by the method of reverse micro-emulsion crosslinking in this work. Starch nanospheres were characterized through Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and dynamic light scattering (DLS). Effects of preparation conditions on particle size were studied. The cytotoxicity, biodegradable and vitro thrombolytic behaviors of nattokinase (NK) loaded anionic starch nanospheres were also studied. The results showed that the anionic starch nanospheres are non-toxic, biocompatible and biodegradable. Moreover, the anionic starch nanospheres can protect NK from fast biodegradation hence prolongs the circulation in vivo and can reduce the risk of acute hemorrhage complication by decreasing the thrombolysis rate.
Co-reporter:Lihua Xie, Shaoyu Lü, Mingzhu Liu, Chunmei Gao, Xinggang Wang, and Lan Wu
Journal of Agricultural and Food Chemistry 2013 Volume 61(Issue 14) pp:3382-3388
Publication Date(Web):March 16, 2013
DOI:10.1021/jf4004016
With the aim of improving fertilizer use efficiency and minimizing the negative impact of nitrogen pollution, a new multifunctional slow-release fertilizer was prepared by recovery of ammonium from aqueous solutions onto a superabsorbent composite. An eco-friendly superabsorbent composite based on wheat straw (WS) was synthesized and used as the carrier to control the release of nutrients. The adsorption studies with NH4+ indicated that the superabsorbent composite showed good affinity for NH4+, with an adsorption capacity of 7.15 mmol g–1 when 20 wt % of WS was incorporated and that the adsorption system can reach equilibrium within 40 min. Afterward, the feasibility of reusing the composite as a multifunctional slow-release nitrogen fertilizer was investigated. The results showed that the product with good water-retention and slow-release capacities could regulate soil acidity and was economical and eco-friendly for application in agriculture and horticulture.
Co-reporter:Xinjie Zhang, Chunmei Gao, Mingzhu Liu, Yinjuan Huang, Xiyong Yu, Enyong Ding
Applied Surface Science 2013 Volume 264() pp:636-643
Publication Date(Web):1 January 2013
DOI:10.1016/j.apsusc.2012.10.084
Abstract
An easy, comprehensive and inexpensive method is demonstrated to produce asymmetric polymer/inorganic nanocomposites in a large quantity. With the aid of Pickering emulsion, unmodified particles aggregate on the surface of emulsion droplets and are fixed in place when the wax solidifies. The exposed surfaces of immobilized SiO2 particles are modified chemically by 2-(dimethylamino) ethylmethacrylate (DMAEMA). With the removal of wax, the exposed side of particles can be further modified chemically by N-isopropylacrylamide (NIPAAm). Based on these procedures, dual responsive asymmetric nanocomposite particles are achieved with both pH and temperature sensitivities. Due to their dual-stimuli and asymmetric structure, these particles have potential applications in molecule targeting, drug delivery and as building blocks for the assembly of complex nanostructure.
Co-reporter:Honghong Gong, Mingzhu Liu, Jiucun Chen, Fei Han, Chunmei Gao, Bing Zhang
Carbohydrate Polymers 2012 Volume 88(Issue 3) pp:1015-1022
Publication Date(Web):15 April 2012
DOI:10.1016/j.carbpol.2012.01.057
Carboxymethyl guar gum was synthesized with a simple dry and multi-step method for the first time as a product of the reaction of guar gum and monochloroacetic acid in the presence of sodium hydroxide. The influences of a variety of reaction parameters for degree of substitution were evaluated. The product was characterized by a variety of material characterization techniques. FTIR showed new bonds at 1618, 1424 and 1325 cm−1 after carboxymethylation. SEM showed that the surface of guar gum particles was mostly ruptured. XRD revealed that guar gum crystallinity was reduced. The rheological properties of product pastes were studied using a rotational viscometer. The viscosity of products’ solution decreased with increasing temperature and increased with increasing concentration. With the increase of storage time, the viscosity increased at first, and then decreased. In addition, a shear thinning pseudoplastic behavior was observed at all concentrations, temperatures and storage times.Highlights► The CMGG is synthesized by a simple dry method. ► The dry method accords with the principle of green chemistry. ► We examine the rheological properties of CMGG solutions in different conditions. ► The dry method has a good developing prospect in lots of industries.
Co-reporter:Yanfang Wang, Mingzhu Liu, Boli Ni, and Lihua Xie
Industrial & Engineering Chemistry Research 2012 Volume 51(Issue 3) pp:1413-1422
Publication Date(Web):December 21, 2011
DOI:10.1021/ie2020526
A multifunctional slow-release nitrogen fertilizer (SRNF) has been developed to improve fertilizer use efficiency and reduce environmental pollution. κ-Carrageenan–sodium alginate (κC–SA) and cross-linked κC-g-poly(acrylic acid)/Celite superabsorbent were used as inner and outer coating materials, which were coated consecutively on the granule core urea in a pan granulator. Elemental analysis result showed that the product contained 22.6% nitrogen. The water evaporation as well as the nitrogen release behavior of SRNF in soil was explored. In addition, the coated urea had a higher average crushing strength in comparison with uncoated urea. Furthermore, the incorporation of SRNF in soil could effectively prevent the compaction of soil. These studies showed that the product prepared by a simple route with good slow-release and water-retention properties may be expected to have wide potential applications in modern agriculture and horticulture.
Co-reporter:Lihua Xie, Mingzhu Liu, Boli Ni, and Yanfang Wang
Industrial & Engineering Chemistry Research 2012 Volume 51(Issue 10) pp:3855-3862
Publication Date(Web):March 5, 2012
DOI:10.1021/ie2016043
With the aim of improving fertilizer use efficiency and minimizing the negative impact on the environment, a new double-coated slow-release nitrogen and phosphorus fertilizer with water retention was prepared. Wheat straw was introduced into the formulations as the basic coating material. Specifically, poly(acrylic acid-co-N-hydroxymethyl acrylamide)/wheat straw superabsorbent composite was used as the outer coating, and wheat straw/sodium alginate blends was used as the inner coating. The degradation of the superabsorbent composite in the soil solution was studied. The impact of the content of wheat straw on the extent of degradation in cellulase solution was also examined. The superabsorbent composite synthesized under the optimal conditions showed super water absorbency and excellent degradability. The water-retention property and the nutrient slow-release behavior of the product were investigated. The results revealed that the product with water-retention and slow-release capacity, being economical, nontoxic in soil, and eco-friendly, could find good application in agriculture and horticulture.
Co-reporter:Boli Ni, Shaoyu Lü, and Mingzhu Liu
Industrial & Engineering Chemistry Research 2012 Volume 51(Issue 40) pp:12993
Publication Date(Web):September 21, 2012
DOI:10.1021/ie3003304
This study was carried out to develop a novel slow-release fertilizer, which is based on natural attapulgite (APT) clay as a matrix, guar gum (GG) as an inner coating, and guar gum-g-poly(itaconic acid-co-acrylamide)/humic acid (GG-g-P(IA-co-AM)/HA) superabsorbent polymer as an outer coating. The coated compound fertilizer granules with diameter in the range of 2–3 mm possess low moisture content and high mechanical hardness. The effects of APT matrix, GG, and superabsorbent polymer coatings on nutrients release were explored. The influence of the product on water-holding capacity of soil was determined. The degradation behavior of the GG-g-P(IA-co-AM)/HA outer coating was assessed by examining the weight loss with incubation time in soil. The experimental data and analysis in this study indicated that the product prepared by a simple route can effectively reduce nutrient loss in runoff or leaching, improve soil moisture content, and regulate soil acidity and alkalinity level.
Co-reporter:Yinjuan Huang, Mingzhu Liu, Jiucun Chen, Chunmei Gao, Qiuyu Gong
European Polymer Journal 2012 Volume 48(Issue 10) pp:1734-1744
Publication Date(Web):October 2012
DOI:10.1016/j.eurpolymj.2012.06.012
In this work, Fe3O4/poly(3-acrylamidephenylboronic acid-co-(2-dimethylamino) ethyl methacrylate) (Fe3O4/P(AAPBA-co-DMAEMA)) hydrogels possessing magnetic and triple-responsive properties and semi-interpenetrated by β-cyclodextrin-epichlorohydrin (β-CD-EPI) were prepared via radical polymerization. The characteristics of the materials have been investigated by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM). The swelling measurements and the application of Fe3O4/P(AAPBA-co-DMAEMA)/(β-CD-EPI) hydrogels in controlled release of drug were also investigated. It was found that the magnetic hydrogels exhibit swelling behaviors affected by pH, temperature, glucose concentration and magnetic field, and have porous morphologies, superparamagnetism. Moreover, the hydrogels possess targeting and could control the release of quercetin by adjusting pH value, temperature, glucose concentration and magnetic field.Graphical abstractSynthesis route of the Fe3O4/P(AAPBA-co-DMAEMA)/(β-CD-EPI) semi-IPN hydrogels.Highlights► A novel magnetic, triple-responsive semi-IPN hydrogels were prepared. ► The swelling measurements and drug release behavior were investigated. ► The swelling behaviors affected by pH, temperature, and glucose concentration. ► The hydrogels have porous morphologies, superparamagnetism. ► The hydrogels possess targeting capacity.
Co-reporter:Lihua Xie, Mingzhu Liu, Boli Ni, and Yanfang Wang
Journal of Agricultural and Food Chemistry 2012 Volume 60(Issue 28) pp:6921-6928
Publication Date(Web):June 25, 2012
DOI:10.1021/jf3001235
With the aim of improving fertilizer use efficiency and minimizing the negative impact on the environment, a new coated controlled-release fertilizer with the function of water retention was prepared. A novel low water solubility macromolecular fertilizer, poly(dimethylourea phosphate) (PDUP), was “designed” and formulated from N,N′-dimethylolurea (DMU) and potassium dihydrogen phosphate. Simultaneously, an eco-friendly superabsorbent composite based on wheat straw (WS), acrylic acid (AA), 2-acryloylamino-2-methyl-1-propanesulfonic acid (AMPS), and N-hydroxymethyl acrylamide (NHMAAm) was synthesized and used as the coating to control the release of nutrient. The nitrogen release profile and water retention capacity of the product were also investigated. The degradation of the coating material in soil solution was studied. Meanwhile, the impact of the content of N-hydroxymethyl acrylamide on the degradation extent was examined. The experimental data showed that the product with good water retention and controlled-release capacities, being economical and eco-friendly, could be promising for applications in agriculture and horticulture.
Co-reporter:Chunmei Gao;Jun Chen ;Chen Chen
Polymers for Advanced Technologies 2012 Volume 23( Issue 3) pp:389-397
Publication Date(Web):
DOI:10.1002/pat.1887
Abstract
A new poly(2-(dimethylamino) ethyl methacrylate)/oxidized sodium alginate (PDMAEMA) semi-interpenetrating network (Semi-IPN) hydrogel with microporous structure was prepared by using PDMAEMA microgels as an additive during the polymerization/crosslinking process. The interior morphology characterized by scanning electron microscopy showed the Semi-IPN hydrogels have different pore sizes by changing the amount of microgels. The hydrogels were also characterized by using Fourier transform infrared and DSC. The swelling behaviors of hydrogels indicated that the hydrogels have excellent pH and temperature sensitivity. Bovine serum albumin was entrapped in the hydrogels and the in vitro drug release profiles were established in different buffer solutions at various temperatures. The release behaviors of the model drug were dependent on the pore size of the hydrogels and environmental temperature/pH, which suggested that these materials have potential application as intelligent drug carriers. Copyright © 2011 John Wiley & Sons, Ltd.
Co-reporter:Liwei Ma;Xiang Shi
Journal of Biomedical Materials Research Part B: Applied Biomaterials 2012 Volume 100B( Issue 2) pp:305-313
Publication Date(Web):
DOI:10.1002/jbm.b.31900
Abstract
A simple method was developed to prepare the microcapsules and microparticles as drug carriers. The drug-loaded microcapsules and microparticles were prepared by self-assembly of carboxymethyl chitosan (CMCTS) and carboxymethyl chitosan-graft-poly(N,N-diethylacrylamide) (CMCTS-g-PDEA) in aqueous media under mild conditions. The preparation method did not involve any organic solvent and surfactant, and it could offer good control over the morphology and the size of self-assemblies. Through adjusting the grafting percentage, nanosized drug-delivery systems with different shapes, that is, microcapsules and microparticles, could be obtained. The grafting reaction was confirmed by comparing the FTIR spectra of CMCTS and the grafted copolymer, and the morphologies of the drug-delivery systems were observed by dynamic light scattering and transmission electron micrograph. Preliminary characterization of the biocompatibility of these microgels was done by the cytotoxicity assays using the L02 human hepatic natural cell as probes. The in vitro bovine serum albumin (BSA) release behavior indicated that drug release rate and encapsulation efficiency depended upon pH value and nanoparticle structure. The release of BSA could be effectively sustained from both drug-loaded microgels, which passed the qualitative cytotoxicity test and have no apparent cytotoxicity for the CMCTS-g-PDEA microgel self-assembly. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 100B: 305–313, 2012.
Co-reporter:Jiucun Chen, Mingzhu Liu, Chen Chen, Honghong Gong, and Chunmei Gao
ACS Applied Materials & Interfaces 2011 Volume 3(Issue 8) pp:3215
Publication Date(Web):July 27, 2011
DOI:10.1021/am2007189
Covalent functionalization of azide-modified SiO2 with well-defined, alkyne-terminated poly(N-isopropylacrylamide) was accomplished by the Cu(I)-catalyzed [3 + 2] Huisgen cycloaddition. The alkyne-terminated RAFT chain transfer agent was first synthesized, and then the alkyne-terminated thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) with different molecular weights were synthesized by the RAFT of NIPAM monomer. The polymerization kinetics and the evolution of number-average molecular weights (Mn), and polydispersities (Mw/Mn), with monomer conversions were investigated. A copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) “grafting to” method was used to attach thermoresponsive polymers onto the exterior surface of SiO2 nanoparticles which produced relatively high grafting density. The as-synthesized hybrid nanoparticles showed thermoresponsive behavior and were characterized by FTIR, XPS, TGA, DLS, and TEM, etc.Keywords: click chemistry; RAFT polymerization; surface modification; thermoresponsive;
Co-reporter:Shaoyu Lü, Bo Li, Boli Ni, Zhihong Sun, Mingzhu Liu and Qin Wang
Soft Matter 2011 vol. 7(Issue 22) pp:10763-10772
Publication Date(Web):27 Sep 2011
DOI:10.1039/C1SM06053H
A major challenge in in vitrocell delivery is to provide an optimum environment that mimics natural conditions to maintain correct cellular functions. To address this challenge, we present a biohybrid injectable hydrogel based on chondroitin sulfate (ChS) and poly(N-isopropylacrylamide) (PNIPAAm). PNIPAAm was synthesized at various molecular weights between 5 to 20 kDa by RAFT polymerization in the presence of S-1-dodecyl-S′-(α, α′-dimethyl-α′′-acetic acid) trithiocarbonate as a chain transfer agent. The molecular weight range suitable for renal clearance was an important factor in the experimental design. The phase transition behavior and the gelation time of the hydrogel were measured to evaluate its possibility for further clinical application. Furthermore, hydrogel degradation was also a concern for clinical application. Samples were incubated in PBS with 100 U/ml of hyaluronidase at 37 °C to determine their degradation behaviors and the results revealed that the hydrogel was biodegradable in physiological conditions. To evaluate the biocompatibility for potential use of the hydrogel as a cell delivery vehicle, in vitro two-dimensional (2-D) and three-dimensional (3-D) cell cultures were performed. Cells demonstrated excellent viability when cultured with the hydrogel. In addition, the arrangement of multiple cell layers in the hydrogel was achieved. These results indicate the thermoresponsive injectable hydrogel may be expected to have wide potential applications as a vehicle for the delivery of therapeutic cells.
Co-reporter:Boli Ni, Mingzhu Liu, Shaoyu Lü, Lihua Xie, and Yanfang Wang
Journal of Agricultural and Food Chemistry 2011 Volume 59(Issue 18) pp:10169-10175
Publication Date(Web):August 17, 2011
DOI:10.1021/jf202131z
To sustain the further world population, more fertilizers are required, which may become an environmental hazard, unless adequate technical and socioeconomic impacts are addressed. In the current study, slow-release formulations of nitrogen fertilizer were developed on the basis of natural attapulgite (APT) clay, ethylcellulose (EC) film, and sodium carboxymethylcellulose/hydroxyethylcellulose (CMC/HEC) hydrogel. The structural and chemical characteristics of the product were examined. The release profiles of urea, ammonium sulfate, and ammonium chloride as nitrogen fertilizer substrates were determined in soil. To further compare the release profiles of nitrogen from different fertilizer substrates, a mathematical model for nutrient release from the coated fertilizer was applied to calculate the diffusion coefficient D. The influence of the product on water-holding and water-retention capacities of soil was determined. The experimental data indicated that the product can effectively reduce nutrient loss, improve use efficiency of water, and prolong irrigation cycles in drought-prone environments.
Co-reporter:Jiucun Chen, Mingzhu Liu, Honghong Gong, Yinjuan Huang, and Chen Chen
The Journal of Physical Chemistry B 2011 Volume 115(Issue 50) pp:14947-14955
Publication Date(Web):November 14, 2011
DOI:10.1021/jp208494w
A well-defined thermoresponsive poly(ethylene glycol)-block-poly(N-isopropylacrylamide)-block-poly(ε-caprolactone) (PEG43-b-PNIPAM82-b-PCL87) triblock copolymer was synthesized by combination of atom transfer radical polymerization (ATRP), ring-opening polymerization (ROP), and click chemistry. The synthesis included the four steps, and all the structures of the polymers were determined. The thermoresponsive triblock copolymer can disperse in water at room temperature to form core–shell–corona micelles with the hydrophobic PCL block as core, the thermoresponsive PNIPAM block as shell, and the hydrophilic PEG block as corona. At temperatures above the lower critical solution temperature (LCST) of the PNIPAM block, the PNIPAM chains gradually collapse on the PCL core to shrink the size and change the structure of the resultant core–shell–corona micelles with temperature increasing.
Co-reporter:Boli Ni, Mingzhu Liu, Shaoyu Lü, Lihua Xie, and Yanfang Wang
Journal of Agricultural and Food Chemistry 2010 Volume 58(Issue 23) pp:12373-12378
Publication Date(Web):November 8, 2010
DOI:10.1021/jf1029306
Multifunctional slow-release organic−inorganic compound fertilizer (MSOF) has been investigated to improve fertilizer use efficiency and reduce environmental pollution derived from fertilizer overdosage. The special fertilizer is based on natural attapulgite (APT) clay used as a matrix, sodium alginate used as an inner coating and sodium alginate-g-poly(acrylic acid-co-acrylamide)/humic acid (SA-g-P(AA-co-AM)/HA) superabsorbent polymer used as an outer coating. The coated multielement compound fertilizer granules were produced in a pan granulator, and the diameter of the prills was in the range of 2.5−3.5 mm. The structural and chemical characteristics of the product, as well as its efficiency in slowing the nutrients release, were examined. In addition, a mathematical model for nutrient release from the fertilizer was applied to calculate the diffusion coefficient D of nutrients in MSOF. The degradation of the SA-g-P(AA-co-AM)/HA coating was assessed by examining the weight loss with incubation time in soil. It is demonstrated that the product prepared by a simple route with good slow-release property may be expected to have wide potential applications in modern agriculture and horticulture.
Co-reporter:Boli Ni, Mingzhu Liu, Shaoyu Lü, Lihua Xie, Xu Zhang and Yanfang Wang
Industrial & Engineering Chemistry Research 2010 Volume 49(Issue 10) pp:4546
Publication Date(Web):April 22, 2010
DOI:10.1021/ie9019769
To improve the utilization of fertilizer and water resources at the same time, a novel slow-release multielement compound fertilizer (SMF) with the function of water retention was prepared. The fertilizer nutrients (11.3% N, 9.6% P2O5, 6.1% K2O, and 0.76% Cu) were entrapped in the alginate matrix granules, and the sodium alginate-g-ploy(acrylic acid) (SA-g-PAA) superabsorbent polymer was used as a coating material. The structural and chemical characteristics of the product as well as its efficiency in slowing nutrient release and water evaporation in soil were examined. The degradation of the SA-g-PAA coating was assessed by examining the weight loss with incubation time in soil. Additionally, the nutrient release mechanism was proposed and the diffusional exponent n was calculated. These studies showed that the product with good slow-release and water-retention properties, being partially degradable in nature, could be expected to have wide potential applications in modern agriculture and horticulture.
Co-reporter:Xiaohua Qi;Zhenbin Chen;Fen Zhang;Lu Zhao
Polymers for Advanced Technologies 2010 Volume 21( Issue 3) pp:196-204
Publication Date(Web):
DOI:10.1002/pat.1416
Abstract
A fast swelling macroporous superabsorbent composite was prepared by the copolymerization of partially neutralized acrylic acid, 2-acryloylamino-2-methyl-1-propanesulfonic acid (AMPS), and attapulgite (APT) using N, N′-methylenebisacrylamide (NNMBA) and trihydroxymethyl propane glycidol ether as crosslinking agents. For fast swelling rate (SR), sodium bicarbonate, polyethylene glycol (PEG), and sodium carboxymethylcellulose (CMC) were introduced into the reaction system as foaming agent and stabilizers. Furthermore, the copolymer was surface-crosslinked with glycerine and sodium silicate, and then blended with aluminum sulfate and sodium carbonate. The influences of the amount of NNMBA, trihydroxymethyl propane glycidol ether, PEG, CMC and sodium bicarbonate, and reaction temperature on water absorbence both under atmospheric pressure and load, and on the SR were investigated. The water absorbence of the sample in 0.9 wt% NaCl aqueous solution under atmospheric pressure and certain load (P ≈ 2 × 103 Pa) could reach 54 and 8 g.g−1, respectively, and the SR could reach 0.471 ml g−1 s−1. The excellent strength, resilience, and the dispersion of swollen hydrogel were also observed for the sample. Moreover, the surface morphology of macroporous superabsorbent composite was characterized using scanning electron microscope. Copyright © 2009 John Wiley & Sons, Ltd.
Co-reporter:Liwei Ma;Hongliang Liu;Jun Chen;Chunmei Gao ;Dapeng Cui
Polymers for Advanced Technologies 2010 Volume 21( Issue 5) pp:348-355
Publication Date(Web):
DOI:10.1002/pat.1434
Abstract
Novel drug-loaded hydrogel beads for intestine-targeted controlled release were developed by using pH- and temperature-sensitive carboxymethyl chitosan-graft-poly(N,N-diethylacrylamide) (CMCTS-g-PDEA) hydrogel as carriers and vitamin B2 (VB2) as a model drug. The hydrogel beads were prepared based on Ca2+ ionic crosslinking in acidic solution and formed dual crosslinked network structure. The structure of hydrogel and morphology of drug-loaded beads were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). The study about swelling characteristics of hydrogel beads indicated that the beads had obvious pH- and temperature-sensitivity. In vitro release studies of drug-loaded beads were carried out in pH 1.2 HCl buffer solution and pH 7.4 phosphate buffer solution at 37°C, respectively. The results indicated that the dual crosslinked method could effectively control the drug release rate under gastrointestinal tract (GIT) conditions, which was superior to traditional single crosslinked beads. In addition, the effects of grafting percentage, pH value, and temperature on the release behavior of the VB2 were investigated. The drug release mechanism of CMCTS-g-PDEA drug-loaded beads was analyzed by Peppa's potential equation. According to this study, the dual crosslinked hydrogel beads based on CMCTS-g-PDEA could serve as suitable candidate for drug site-specific carrier in intestine. Copyright © 2009 John Wiley & Sons, Ltd.
Co-reporter:Lu Zhao;Yun Xiong;Xiaohua Qi
Polymers for Advanced Technologies 2010 Volume 21( Issue 7) pp:483-489
Publication Date(Web):
DOI:10.1002/pat.1456
Abstract
A series of superabsorbents of maleic anhydride (MAH)/acrylamide (AM) interpenetrated with poly(vinyl alcohol) (PVA) were prepared by aqueous polymerization, using N,N-methylenebiacrylamide (NNMBA) as a crosslinker and ammonium persulfate (APS) as an initiator. The samples were characterized by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and scanning electron microscope (SEM). The effects of reaction variables on the water absorbency of the superabsorbents in distilled water and in 0.9 wt% NaCl solution were investigated. In addition, the effect of the PVA content on the swelling rate and sensitivity to saline of the superabsorbents were also investigated. The results showed that the absorbency, both in 0.9 wt% NaCl solution and in distilled water, first decreased and then increased with increasing PVA content. Moreover, the resultant superabsorbent had a higher absorption rate and it became less sensitive to saline by incorporating certain amount of PVA into the network of the hydrogel. Copyright © 2009 John Wiley & Sons, Ltd.
Co-reporter:Shuping Jin, Mingzhu Liu, Shilan Chen, Chunmei Gao
Materials Chemistry and Physics 2010 Volume 123(2–3) pp:463-470
Publication Date(Web):1 October 2010
DOI:10.1016/j.matchemphys.2010.04.042
A drug-loaded gel (CSPP) based on ionic crosslinked chitosan (CS) and polyelectrolyte complexes of poly (acrylic acid) (PAA) with poly (vinylpyrrolidone) (PVP) was prepared by dropping CS solution containing suitable amount of PVP into PAA and trisodium citrate co-existing gelling solution. The surface and cross-section morphology of the gel was observed using scanning electron microscopy, and the observation showed that the CSPP gel had more compact structure than CS gel. In vitro release profiles of model drug from the CSPP gel, which was prepared under different conditions, were investigated in simulative gastric fluid (pH 1.8) using an UV/vis spectrophotometer. The results showed that the rapid release of the model was restrained due to the complex of PVP and PAA, and the CSPP gel could serve as a suitable candidate in drug delivery system such as the site-specific controlled release of the drug in stomach. In addition, the release mechanism of drug was analyzed by fitting the amount of drug released into Peppa's potential equation.
Co-reporter:Shaoyu Lü;Boli Ni ;Chunmei Gao
Journal of Polymer Science Part B: Polymer Physics 2010 Volume 48( Issue 15) pp:1749-1756
Publication Date(Web):
DOI:10.1002/polb.22040
Abstract
Poly(N-vinyl-pyrrolidone) (PVP) hydrogel has been considered as a very interesting and promising thermosensitive material. The most vital shortcoming of PVP hydrogel as thermosensitive material is that it does not exhibit thermosensitivity under usual conditions. In this work, semi-interpenetrating polymer network (semi-IPN) hydrogels based on PVP and carboxymethylcellulose (CMC) were prepared. The volume phase transition temperature (VPTT) of the hydrogels was determined by swelling behavior and differential scanning calorimetry (DSC). The results showed that the VPTT was significantly dependent on CMC content and the pH of the swelling medium. The amount of CMC in the semi-IPN hydrogels was 0.050, 0.075, and 0.100 g, the VPTT in buffer solution of pH 1.2 was 29.9 °C, 27.5 °C and 24.5 °C, respectively. In addition, the VPTT occurred in buffer solution of pH 1.2, but did not appear in alkaline medium. Bovine serum albumin (BSA) as a model drug was loaded and the in vitro release studies were carried out in different buffer solutions and at different temperatures. The results of this study suggest that PVP/CMC semi-IPN hydrogels could serve as potential candidates for protein drug delivery in the intestine. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1749–1756, 2010
Co-reporter:Jun Chen, Mingzhu Liu, Naiyan Zhang, Peipei Dai, Chunmei Gao, Liwei Ma, Hongliang Liu
Sensors and Actuators B: Chemical 2010 Volume 149(Issue 1) pp:34-43
Publication Date(Web):6 August 2010
DOI:10.1016/j.snb.2010.06.034
The poly(N,N-diethylacrylamide-co-(2-dimethylamino)ethyl methacrylate) (poly(DEA-co-DMAEMA)) macromonomers with three different chain lengths were prepared by telomerization of DEA and DMAEMA monomers with different ratios of the chain transfer agent, 2-mercaptoethanol. The number-average weight of three macromonomers determined by gel permeation chromatography of the terminal hydroxyl groups was 8355, 10,516 and 15,953, respectively. The comb-type grafted poly(DEA-co-DMAEMA) hydrogels having the different lengths of the grafted chains were synthesized in the presence of crosslinker. Equilibrium and dynamic swelling/deswelling properties of the prepared hydrogels responding to temperature and pH were investigated. Compared to normal-type hydrogel, the comb-type grafted hydrogels exhibited excellent variational values in response to an alternation of the temperature and pH. Moreover, the grafted hydrogels showed quite fast reswelling and deswelling behaviors in response to simultaneous dual temperature and pH stimuli. This is because that the introduction of side chains with freely mobile ends in the comb-type grafted hydrogels made the mobility of the networks increased. The responsive rates of the grafted hydrogels were also controlled by modifying the length of the grafted chains. The dual thermo- and pH-sensitive comb-type grafted poly(DEA-co-DMAEMA) hydrogels in this study may find various potential applications.
Co-reporter:Lu Wang, Mingzhu Liu, Chunmei Gao, Liwei Ma, Dapeng Cui
Reactive and Functional Polymers 2010 70(3) pp: 159-167
Publication Date(Web):March 2010
DOI:10.1016/j.reactfunctpolym.2009.11.007
Co-reporter:Hongliang Liu, Mingzhu Liu, Lijing Zhang, Liwei Ma, Jun Chen, Yunjiao Wang
Reactive and Functional Polymers 2010 70(5) pp: 294-300
Publication Date(Web):May 2010
DOI:10.1016/j.reactfunctpolym.2010.02.002
Co-reporter:Chunmei Gao, Mingzhu Liu, Jun Chen, Xu Zhang
Polymer Degradation and Stability 2009 Volume 94(Issue 9) pp:1405-1410
Publication Date(Web):September 2009
DOI:10.1016/j.polymdegradstab.2009.05.011
Degradation is often a critical property of materials utilized in tissue engineering. Although alginate, a naturally derived polysaccharide, is an attractive material due to its biocompatibility and ability to form hydrogels, its slow and uncontrollable degradation can be an undesirable feature. In this study, the degradation behavior of hydrogel based on oxidized sodium alginate (OSA) crosslinked with Ca2+ was studied in phosphate buffer solution (PBS, pH = 7.4) and Tris-(hydroxymethyl) aminomethane–HCl (Tris–HCl, pH = 7.4) at 37 °C. The degradation behavior of OSA hydrogels with different degrees of oxidation was evaluated as a function of degradation time by monitoring the changes of molecular weight and weight loss. It was found that the degradation behavior relied heavily on the degree of oxidation and the surrounding medium. This result indicates that the degradation rates of OSA hydrogels can be controlled by changing the degree of oxidation.
Co-reporter:Hongliang Liu, Mingzhu Liu, Liwei Ma, Jun Chen
European Polymer Journal 2009 Volume 45(Issue 7) pp:2060-2067
Publication Date(Web):July 2009
DOI:10.1016/j.eurpolymj.2009.03.019
Poly(N,N-diethylacrylamide) with a terminal hydroxyl end group (PDEA-OH) was synthesized by radical telomerization of N,N-diethylacrylamide (DEA) monomer using 2-hydroxyethanethiol as a chain transfer agent. Macromonomer of thermo-sensitive PDEA was synthesized by condensation reaction of PDEA-OH with acryloyl chloride. The macromonomer was characterized by FTIR and 1H NMR, and the molecular weight was determined by GPC. Thermo- and pH-sensitive comb-type grafted poly(N,N-diethylacrylamide-co-acrylic acid) (PDEA-co-AA) hydrogels (GHs) were successfully prepared by grafting PDEA chains with freely mobile ends onto the backbone of a cross-linked (PDEA-co-AA) network. The results showed that the deswelling behavior of the hydrogels was dependent on the test temperature. At 45 °C (beneath the VPTT of the hydrogels), both the normal-type hydrogels (NHs) and comb-type grafted P(DEA-co-AA) hydrogels had lower deswelling rates. While at 60 °C (far beyond the VPTT of the hydrogels), the deswelling rates of the GHs were faster than that of the NHs. Furthermore, pulsatile stimuli-responsive studies indicated that the GHs had excellent thermo-reversibility and were superior to the NHs in the magnitude of their swelling ratios to temperature changes. However, the reversibility to pH changes was poor for both the NHs and the GHs.
Co-reporter:Shuping Jin;Fengling Bian;Shilan Chen;Hongliang Liu
Polymer International 2009 Volume 58( Issue 2) pp:142-148
Publication Date(Web):
DOI:10.1002/pi.2504
Abstract
BACKGROUND: The objective of the work reported was to investigate the effect of gel microstructure on the swelling mechanism. A series of porous gels with various pore sizes were prepared by freeze-treating a conventional hydrogel that contained various amounts of water at − 20 °C. Scanning electron microscopy and differential scanning calorimetry were used to characterize the microstructure of the porous gels.
RESULTS: The experimental results showed that the water content during freezing was the key factor controlling the microstructure. Measurement of swelling kinetics showed that a greater amount of water during the freezing process would lead to a rapid swelling rate. The apparent diffusion coefficients (Dp) at all times during the swelling process were obtained by fitting the experimental data to the diffusion equation. The values of Dp suggested that the swelling mechanism of the gels depends on the pore size. The diffusion exponent (n) obtained by fitting the fractional mass change (Mt/M∞) to equation of Fick's law further confirmed that the swelling mechanism of the gels is determined by the pore size.
CONCLUSION: The swelling mechanism of the gels is determined by the microstructure related to the pore size and the thickness of struts. The microstructure can be controlled by adjusting the water content of the hydrogels by changing the pH of the swelling medium prior to freezing. Copyright © 2008 Society of Chemical Industry
Co-reporter:Jun Chen, Mingzhu Liu, Shilan Chen
Materials Chemistry and Physics 2009 Volume 115(Issue 1) pp:339-346
Publication Date(Web):15 May 2009
DOI:10.1016/j.matchemphys.2008.12.026
In this study, a novel semi-interpenetrating polymer network (semi-IPN) hydrogel of kappa-carrageenan-g-poly(methacrylic acid)/poly(N,N-diethylacrylamide) (KC-g-PMAA/PDEA) was prepared using ammonium persulfate as an initiator and N,N,N′,N′-tetramethylethylenediamide as an accelerator at 25 °C. The structure of the hydrogels was characterized by Fourier transform infrared spectroscopy and scanning electron microscope. The effects of the feed components, temperature and pH on the swelling behavior of the hydrogels were studied. The results showed that the introduction of KC-g-PMAA did not change the lower critical solution temperature of the semi-IPN hydrogels, which was the same to the PDEA hydrogel (at 28 °C). With the increase of KC-g-PMAA content, the thermo- and pH-sensitivity of the hydrogel improved, which the swelling rate increased with the increasing content of KC-g-PMAA. The semi-IPN hydrogels showed a fast deswelling and swelling rate. The swelling dynamic transport of the hydrogels was analyzed based on the Fickian equation.
Co-reporter:Hongliang Liu;Jing Huang;Liwei Ma;Jun Chen
Polymers for Advanced Technologies 2009 Volume 20( Issue 12) pp:1152-1156
Publication Date(Web):
DOI:10.1002/pat.1391
Abstract
Fast responsive temperature- and pH-sensitive hydrogels of poly(N,N-diethylacrylamide-co-acrylic acid) (P(DEA-co-AA)) have been synthesized successfully by a two-step procedure, in which the initial polymerization was conducted at constant temperature for 15 min, followed by further polymerization at −30°C for 12 hr. Swelling studies showed that hydrogels thus prepared had almost the same temperature and pH sensitivity compared with the conventional ones (polymerized at 24°C for 12 hr). However, hydrogels thus prepared had faster swelling/deswelling rates in distilled water than the conventional ones, and their deswelling rates in low pH buffer solutions were also faster than the conventional ones. These improved properties were attributed to the porous network structure, which was confirmed by the results of scanning electron microscopy. Copyright © 2009 John Wiley & Sons, Ltd.
Co-reporter:Yinghui Bi;Lan Wu ;Dapeng Cui
Journal of Applied Polymer Science 2009 Volume 113( Issue 1) pp:24-33
Publication Date(Web):
DOI:10.1002/app.29829
Abstract
To optimize the preparation conditions of carboxymethyl potato starch (CMPS), the effects of relevant factors on viscosity (η) of 2% CMPS aqueous solution and degree of substitution (DS) were investigated. These condition parameters included etherification temperature, alkalization and etherification time, water content in the mixed solvent, ratio of liquid volume to starch mass, molar ratio of sodium hydroxide to monochloroacetic acid, and molar ratio of monochloroacetic acid to anhydroglucose unit. After individual parameter influencing η and DS was researched one by one, an orthogonal experiment of L18 (2 × 37) was designed to identify the main factors affecting them. In light of range analysis, the comparative importance of factors impacting η and DS was obtained, separately. Results of variance analysis showed that the most effective factor to control DS was etherification temperature, whereas the influences of all factors on η were not significant. Meanwhile, η and DS of the optimized final product were found to be 12,000 mPa.s and 0.68, respectively. In addition, the structure of CMPS was characterized by Fourier transform infrared (FTIR) spectrophotometer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Co-reporter:Liwei Ma;Jun Chen;Hongliang Liu;Dapeng Cui ;Chunmei Gao
Advanced Engineering Materials 2009 Volume 11( Issue 12) pp:B267-B274
Publication Date(Web):
DOI:10.1002/adem.200900149
Abstract
In this work, the carboxymethyl chitosan (CMCTS) grafted poly(N-vinylpyrrolidone) (PVP) copolymers were synthesized. The hydrogel beads containing VB2 were prepared from the copolymers by an ionic crosslinked. The experimental results shown that VB2 drug release rate from those beads decreased with the increasing grafting percentage, crosslinker concentration and pH value of the medium. Besides, the beads have the better control ability for releasing of model drug than CMCTS does.
Co-reporter:Jun Chen, Mingzhu Liu, Hongliang Liu, Liwei Ma
Materials Science and Engineering: C 2009 29(7) pp: 2116-2123
Publication Date(Web):
DOI:10.1016/j.msec.2009.04.008
Co-reporter:Xiaohua Qi;Fen Zhang ;Zhenbin Chen
Polymer Engineering & Science 2009 Volume 49( Issue 1) pp:182-188
Publication Date(Web):
DOI:10.1002/pen.21238
Abstract
A novel salt-resistant superabsorbent composite was prepared by copolymerization of partially neutralized acrylic acid, 2-acryloylamino-2-methyl-1-propanesulfonic acid (AMPS) and attapulgite (APT). To enhance the swelling rate (SR) of the copolymer, sodium bicarbonate was used as a foaming agent in the course of copolymerization. Furthermore, for improving the properties of swollen hydrogel, such as strength, resilience and dispersion, the copolymer was surface-crosslinked with glycerine and sodium silicate, and then the surface-crosslinked copolymer was blended with aluminum sulfate and sodium carbonate in post treatment process. The influences of some reaction conditions, such as amount of AMPS, APT, and initiator, and neutralization degree of acrylic acid on water absorbency in 0.9 wt% NaCl aqueous solution both under atmospheric pressure (WA) and load (WAP, P ≈ 2 × 103 Pa) were investigated. In addition, the effect of them on SR was also studied. The WA and WAP of the superabsorbent composite prepared under optimal conditions in 0.9 wt% NaCl aqueous solution were 52 g·g−1 and 8 g·g−1, respectively. Besides, the SR was fast, and it could reach 0.393 mL·(g·s)−1. Moreover, the swollen hydrogel possessed excellent salt resistance, hydrogel resilience and dispersion. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers
Co-reporter:Lan Wu, Mingzhu Liu
Carbohydrate Polymers 2008 Volume 72(Issue 2) pp:240-247
Publication Date(Web):5 May 2008
DOI:10.1016/j.carbpol.2007.08.020
To improve the utilization of fertilizer and water resource at the same time, a new type chitosan-coated nitrogen, phosphorus and potassium compound fertilizer with controlled-release and water-retention (CFCW) was prepared, which possessed the three-layer structure. Its core was water-soluble nitrogen, phosphorus and potassium (NPK) fertilizer granular, the inner coating was chitosan (CTS), and the outer coating was poly(acrylic acid-co-acrylamide) (P(AA-co-AM)) superabsorbent polymer. Atomic absorption spectrophotometer and element analysis results showed that the product contained 7.98% potassium (shown by K2O), 8.14% phosphorus (shown by P2O5), and 8.06% nitrogen. The synthesis conditions of inversion suspension polymerization were studied systematically. The water absorbency of the product was 70 times its own weight if it was allowed to swell in tap water at room temperature for 90 min. The nutrients slow release behaviors of the CFCW in soil and water-retention capacity of the soil with CFCW were investigated. A possible slow release mechanism was proposed and the release rate factor K and the release exponent n of nutrients in CFCW was calculated. This product with good controlled-release and water-retention capacity, being degradable in soil and environment-friendly, could be especially useful in agricultural and horticultural applications.
Co-reporter:Bin Wang;Ming-Zhu Liu;Rui Liang;Sheng-Long Ding;Zhen-Bin Chen;Shi-Lan Chen;Shu-Ping Jin
Macromolecular Bioscience 2008 Volume 8( Issue 5) pp:417-425
Publication Date(Web):
DOI:10.1002/mabi.200700176
Co-reporter:Shuping Jin, Mingzhu Liu, Shilan Chen, Chunmei Gao
European Polymer Journal 2008 Volume 44(Issue 7) pp:2162-2170
Publication Date(Web):July 2008
DOI:10.1016/j.eurpolymj.2008.04.017
In this study, a poly(N-vinylpyrrolidone)-graft-poly(N-isopropylacrylamide) hydrogel (PVP-g-PNIPAM) was synthesized through the “grafting from” process. Grafting of temperature responsive poly(N-isopropylacrylamide) (PNIPAM) brushes was carried out from the poly(N-vinylpyrrolidone) (PVP) synthesized with free radical polymerization and functionalized with ATRP initiator, PVP–Br, which was performed through a bromination reaction between pendant allylic groups of the PVP and N-bromosuccinimide (NBS). The structure of the initiator and PVP-g-PNIPAM was characterized by ultraviolet and visible (UV/Vis) absorption, nuclear magnetic resonance (NMR) spectroscopy and Fourier transform infrared (FTIR) measurements. Scanning electron microscope (SEM) morphology measurement displayed some dendritic grafted chains dangling onto the pore wall of the hydrogel.The characteristic in response to the change in environmental temperature was investigated by the fluorescence anisotropy and UV/Vis transmittance measurements. The results showed that the PVP-g-PNIPAM hydrogel exhibited rapid response to the change in environmental temperature due to free and mobile graft chains compared with the P(VP-co-NIPAM) hydrogel, which was prepared by free radical copolymerization in this work.
Co-reporter:Xiaohua Qi, Mingzhu Liu, Zhenbin Chen, Fen Zhang
European Polymer Journal 2008 Volume 44(Issue 3) pp:743-754
Publication Date(Web):March 2008
DOI:10.1016/j.eurpolymj.2007.12.010
Open circuit potential measurement was used to trace the swelling kinetics of superabsorbent. The calibration curve and its fitting result showed the validity of the method in determining the concentration of chloride ion in aqueous solution. According to the regression analysis and theoretical derivation, the relationship between the open circuit potential change and the swelling ratio was obtained. Comparing with tea bag method, it was verified that open circuit potential measurement could be employed to trace the swelling kinetics of superabsorbent. The hysteresis effect of solute entering into superabsorbent and the overflow of soluble parts of hydrogel were also observed. Besides, we found that the entrance of solute and water were almost synchronal, and the concentration of solution absorbed by superabsorbent was lower than that of swelling medium. Moreover, the swelling model of superabsorbent in salting liquid was slightly modified.
Co-reporter:Hongliang Liu;Shuping Jin;Shilan Chen
Polymer International 2008 Volume 57( Issue 10) pp:1165-1173
Publication Date(Web):
DOI:10.1002/pi.2460
Abstract
BACKGROUND: A considerable amount of research has been focused on smart hydrogels that can respond to external environmental stimuli, especially temperature and pH. In this study, fast responsive thermo- and pH-sensitive poly[(N,N-diethylacrylamide)-co-(acrylic acid)] hydrogels were prepared by free radical copolymerization in aqueous solution using poly(ethylene glycol) (PEG) as a pore-forming agent.
RESULTS: Swelling studies showed that the hydrogels produced had both temperature and pH sensitivity. The deswelling kinetics at high temperature demonstrated that the shrinking rates were influenced by the addition of the pore-forming agent and the amount of acrylic acid in the initial total monomers. The deswelling curves in low-buffer solutions had two stages. Pulsatile swelling studies indicated that the PEG-modified hydrogels were superior to the normal ones. These different swelling properties were further confirmed by the results of scanning electron microscopy.
CONCLUSION: Such fast responsive thermo- and pH-sensitive hydrogels are expected to be useful in biomedical fields for stimuli-responsive drug delivery systems. Copyright © 2008 Society of Chemical Industry
Co-reporter:Lan Wu
Polymers for Advanced Technologies 2008 Volume 19( Issue 7) pp:785-792
Publication Date(Web):
DOI:10.1002/pat.1034
Abstract
A novel cellulose acetate-coated compound fertilizer with controlled-release and water-retention (CAFCW) was prepared, which possessed the three-layer structure. Its core was water-soluble compound fertilizer granular, the inner coating was cellulose acetate (CA), and the outer coating was poly(acrylic acid-co-acrylamide)/unexpanded vermiculite (P(AA-co-AM)/UVMT) superabsorbent composite. The effects of the amount of acrylamide, crosslinker, initiator, degree of neutralization of acrylic acid (AA), and unexpanded vermiculite concentration on water absorbency were investigated and optimized. The water absorbency of CAFCW was 72 times its own weight if it was allowed to swell in tap water at room temperature for 90 min. Element analysis and atomic absorption spectrophotometer results showed that the product contained 11% nitrogen, 6% phosphorus (shown by P2O5), 9% potassium (shown by K2O), 1% calcium (shown by CaO), and 0.4% magnesium (shown by MgO). Swelling rate, slow-release, and water-retention properties of CAFCW were also investigated. This product with good controlled-release and water-retention capacity, being degradable in soil and environmentally friendly, could be especially useful in agricultural and horticultural applications. Copyright © 2008 John Wiley & Sons, Ltd.
Co-reporter:Yinghui Bi;Lan Wu ;Dapeng Cui
Polymers for Advanced Technologies 2008 Volume 19( Issue 9) pp:1185-1192
Publication Date(Web):
DOI:10.1002/pat.1102
Abstract
Carboxymethyl potato starch (CMPS) was synthesized under heterogeneous reaction conditions. The influences of etherification temperature, alkalization and etherification time, sodium hydroxide to monochloroacetic acid (MCA) molar ratio (nNaOH/nMCA), theoretical degree of substitution (DSt), the ratio of isopropyl alcohol (IPA) volume to starch mass (vIPA/mst) on degree of substitution (DS) and reaction efficiency (RE) of CMPS were investigated. Compared with the previous literature data, the results had significant difference for the optimal carboxymethylation conditions of potato starch from different sources. CMPS prepared under optimal conditions showed the highest DS and RE, which were 1.36 and 0.88, respectively. Furthermore, the RE value in this work is considerably higher than that reported in the literature. The time of alkalization and etherification were also discussed independently. In addition, CMPS was characterized by Fourier transform infrared spectrophotometry and scanning electron microscopy (SEM). Copyright © 2008 John Wiley & Sons, Ltd.
Co-reporter:Jun Chen;Shuping Jin;Hongliang Liu
Polymers for Advanced Technologies 2008 Volume 19( Issue 11) pp:1656-1663
Publication Date(Web):
DOI:10.1002/pat.1184
Abstract
In this study, a novel classical thermo- and salt-sensitive semi-interpenetrating polymer network (semi-IPN) hydrogel composed of poly(N,N-diethylacrylamide) (PDEAm) and κ-carrageenan (KC) was synthesized by free radical polymerization. The structure of the hydrogels was studied by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). FTIR and SEM revealed that the semi-IPN hydrogels possessed the structure of H-bonds and larger number of pores in the network. Compared to the PDEAm hydrogel, the prepared semi-IPN hydrogels exhibited a much faster response rate to temperature changes and had larger equilibrium swelling ratios at temperatures below the lower critical solution temperature (LCST). The salt-sensitive behavior of the semi-IPN hydrogels was dependent on the content of KC. In addition, during the reswelling process, semi-IPN hydrogels showed a non-sigmoidal swelling pattern. Copyright © 2008 John Wiley & Sons, Ltd.
Co-reporter:Shenglong Ding;Haibin Fang
Journal of Applied Polymer Science 2008 Volume 108( Issue 1) pp:423-430
Publication Date(Web):
DOI:10.1002/app.27302
Abstract
Melt grafting of acrylic acid (AA) and butyl acrylate (BA) (equal molar ratios) onto low-density polyethylene (LDPE) was carried out in Haake internal mixter by free radical grafting copolymerization. The graft degree of AA and BA in the grafted LDPE (LDPE-g-(AA+BA)) was determined by FTIR. The influences of initiator on the graft degree of AA and BA, melt flow rate (MFR), and gel content were investigated, and the optimum conditions were obtained. The successive self-nucleation/annealing (SSA) thermal fraction method was used to characterize the molecular structure and polydispersity of LDPE-g-(AA+BA) with various graft degrees. The effects of thermal fraction parameters on fraction of LDPE-g-(AA+BA) were investigated. On the basis of the results of SSA, the grafting reaction mechanism of AA and BA onto LDPE was proposed, i.e., grafting reaction preferentially occurred on the tertiary carbons of LDPE. The grafted LDPE possessed suitable reactivity and rheological property. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Co-reporter:Hongliang Liu;Fengling Bian;Shilan Chen
Journal of Applied Polymer Science 2008 Volume 109( Issue 5) pp:3037-3043
Publication Date(Web):
DOI:10.1002/app.28439
Abstract
A series of thermo- and pH-sensitive poly (N,N-diethylacrylamide-co-acrylic acid) (P(DEA-co-AA)) hydrogels were prepared in NaCl aqueous solutions with different concentrations. Swelling and deswelling studies showed that in comparison with conventional P(DEA-co-AA) hydrogels (prepared in distilled water), the P(DEA-co-AA) hydrogels thus prepared had almost the same volume phase transition temperature (VPTT), but exhibited much faster response rates as the temperature was raised above their VPTT. Besides, the hydrogels prepared by this method had faster response rates in low pH buffer solutions, and the response rates increased with the increased concentration of the NaCl solutions used during the polymerization. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Co-reporter:Shuping Jin;Shilan Chen;Chunmei Gao
Macromolecular Chemistry and Physics 2008 Volume 209( Issue 4) pp:410-416
Publication Date(Web):
DOI:10.1002/macp.200700466
Co-reporter:Liwei Ma, Mingzhu Liu, Hongliang Liu, Jun Chen, Dapeng Cui
International Journal of Pharmaceutics (29 January 2010) Volume 385(Issues 1–2) pp:86-91
Publication Date(Web):29 January 2010
DOI:10.1016/j.ijpharm.2009.10.037
A simple method has been developed to prepare smart P(N,N-diethylacrylamide-co-methacrylic acid) (P(DEA-co-MAA)) microspheres that consist of well-defined temperature-sensitive cores and pH sensitive shells. The microgels have been prepared by surfactant-free emulsion polymerization using water as the solvent. The core–shell hydrogel microspheres have been characterized by Fourier transform infrared (FTIR) spectroscopy, UV spectrometry, dynamic light scattering (DLS) and transmission electron micrograph (TEM). Preliminary characterization of the biocompatibility of hydrogel microspheres has been done by the cytotoxicity assays using the HeLa human breast cancer cell line as probes. The in vitro drug release indicates that drug release rate, encapsulation efficiency (EE) and release kinetics depend upon the pH value and copolymer composition. According to this study, the hydrogel microspheres based on P(DEA-co-MAA) could serve as suitable candidate for drug site-specific carrier in intestine.
Co-reporter:Boli Ni, Mingzhu Liu, Shaoyu Lü
Chemical Engineering Journal (15 December 2009) Volume 155(Issue 3) pp:892-898
Publication Date(Web):15 December 2009
DOI:10.1016/j.cej.2009.08.025
The aim of this study was to prepare a double-coated, slow-release, and water-retention urea fertilizer (DSWU) to reduce environment pollution derived from excessive nitrogen fertilizer use. Ethylcellulose (EC) and crosslinked poly(acrylic acid-co-acrylamide) (P(AA-co-AM)) were used as inner and outer coating materials, respectively. The structural and chemical characteristics of the product, as well as its efficiency in slowing the nitrogen release and water evaporation in soil were examined. The nitrogen content of the product was 21.1% and its water absorbency was 70 times its own weight in tap water. Additionally, the biodegradation of EC coating in soil was assessed by differential scanning calorimetry (DSC) measurements. The results showed that the glass transition temperature (Tg) of EC coating decreased with the time prolonged, which indicated the biodegradability of EC coating in soil. These studies showed that the product with good slow-release and water-retention properties, being environmentally friendly, would find good application in agriculture and horticulture.
Co-reporter:Shaoyu Lü, Mingzhu Liu, Boli Ni
Chemical Engineering Journal (1 June 2010) Volume 160(Issue 2) pp:779-787
Publication Date(Web):1 June 2010
DOI:10.1016/j.cej.2010.03.072
This work is focused on the development of a new injectable drug delivery system for proteins sustained release. A series of in situ forming hydrogels derived from oxidized carboxymethylcellulose (OCMC) and N-succinyl-chitosan (NSC) were prepared by Schiff base reaction. OCMC was prepared by cleaving the vicinal glycols in carboxymethylcellulose with sodium periodate and NSC was obtained by introduction of succinyl groups into chitosan N-terminal of the glucosamine units, respectively. The gelation readily took place at physiological pH and temperature. Several parameters, such as matrix gelation time, equilibrium swelling ratio, matrix degradation rate and drug release profile, were investigated. The in vitro cytotoxicity studies showed that the OCMC/NSC hydrogels were non-cytotoxic and preserved the viability of the entrapped cells. The release profile of BSA was divided into four stages, indicating that the release of BSA was controlled by both diffusion and degradation. Importantly, activity of released BSA was retained regardless of the oxidation degree. This newly described OCMC/NSC hydrogels demonstrated attractive properties and would be a suitable injectable and biodegradable system for the delivery of protein drugs.
Co-reporter:Yang Wang, Chen Hou, Yun Zhang, Fu He, Mingzhu Liu and Xiaoli Li
Journal of Materials Chemistry A 2016 - vol. 4(Issue 21) pp:NaN3702-3702
Publication Date(Web):2016/04/18
DOI:10.1039/C6TB00276E
A novel amperometric biosensor for glucose detection was fabricated based on a mimetic multi-enzyme system by combing mimetic enzymes (metal–organic frameworks, MOFs) and glucose oxidase (GOx). The microcapsule constructed with polydopamine (PDA) and ZIF-8 using CaCO3 templates could be utilized not only to provide the biocompatible and non-toxic microenvironment to immobilize GOx, but also as an efficient mimetic enzyme because of the peroxidase-like properties of ZIF-8. The graphene nano-sheets (rGO) were bonded to the PDA/ZIF-8 microcapsules to accelerate the electron transfer between the microcapsule and the electrode, and the resulted PDA/ZIF-8@rGO showed excellent electro-catalytic activity towards H2O2. The mimetic multi-enzyme system was fabricated when GOx was immobilized in the as-prepared microcapsule, and the developed GOx/PDA/ZIF-8@rGO/GCE biosensor exhibited extraordinary electro-detection performance for glucose with two wide linear ranges from 1 μM to 1.2 mM and 1.2 mM to 3.6 mM, and the limit of detection was 0.333 μM (S/N = 3). Moreover, the good selectivity for glucose and satisfactory detection results in real samples of the prepared biosensor were also demonstrated.
Co-reporter:Shaoyu Lü, Xiao Bai, Haidi Liu, Piao Ning, Zengqiang Wang, Chunmei Gao, Boli Ni and Mingzhu Liu
Journal of Materials Chemistry A 2017 - vol. 5(Issue 20) pp:NaN3748-3748
Publication Date(Web):2017/04/11
DOI:10.1039/C7TB00776K
Current hydrogels based on chondroitin sulfate (ChS) generally lack the necessary strength and precise mechanical tunability. Addressing these limitations, covalent cross-linking has evolved to produce hydrogels with desirable properties. However, such a methodology always precludes injection and self-healing. In this study, we employ DA click chemistry and dynamic acylhydrazone bond cross-linking for hydrogel formation that overcomes the limitations of current ChS hydrogels. Dynamic acylhydrazone bonds afford the hydrogel injectability and self-healing ability, while DA click chemistry facilitates the employment of covalent crosslinking for stabilization in vivo and modulating hydrogel properties in vivo. The study reveals that the obtained hydrogel possesses highly tunable viscoelastic and rheological properties, swelling and degradation behavior, and injectability and self-healing ability compared with ChS hydrogels cross-linked by single DA click chemistry or acylhydrazone bonds. Meanwhile, this hydrogel shows increased viability and reduced apoptosis of rat mesenchymal stem cells, and excellent tissue adhesive ability in vivo. The hydrogel was loaded with BMP-4 and used as a scaffold for rat cranial bone tissue engineering. The results demonstrated that new bone tissue was detected in the defected area of the cranial bone. Thus, this cytocompatible, injectable and self-healing hydrogel with tunable properties can be used as a scaffold for cranial bone tissue engineering and promote bone formation.
Co-reporter:Chunmei Gao, Mingzhu Liu, Shaoyu Lü, Xinjie Zhang and Haogang Duan
Journal of Materials Chemistry A 2014 - vol. 2(Issue 39) pp:NaN6829-6829
Publication Date(Web):2014/08/14
DOI:10.1039/C4TB01186D
Supramolecular systems were constructed by the non-covalent coupling between PAMAM dendrimers with adamantyl groups and β-cyclodextrin graft PNIPAAm through host–guest interactions. Such supramolecular systems can further self-assemble into nanorods, which have thermoresponsive and excellent fluorescence properties. The injectable and percutaneous detection of fluorescent supramolecular systems will be of significant advantage in the future of biomedical monitoring.
Co-reporter:Xinjie Zhang, Chunmei Gao, Shaoyu Lü, Haogang Duan, Nannan Jing, Di Dong, Caifeng Shi and Mingzhu Liu
Journal of Materials Chemistry A 2014 - vol. 2(Issue 33) pp:NaN5460-5460
Publication Date(Web):2014/06/25
DOI:10.1039/C4TB00905C
Optical glucose detection holds considerable promise for continuous in vivo glucose monitoring with wireless transdermal transmission and long-lasting activity. To construct a new class of optical glucose nanobiosensors with high sensitivity and selectivity at physiological conditions, the first generation of fluorescent poly(amido amine) (G1.0 PAMAM), serving as the optical code, was introduced into glucose-sensitive poly(N-isopropylacrylamide-(2-dimethylamino)ethyl methacrylate-3-acrylamidephenylboronic acid) copolymer microgels via a facile method. The fabricated microgels display the ability of adapting to the surrounding medium of different glucose concentrations over a clinically relevant range (0–20 mM) and convert biochemical signals into optical signals. As nanobiosensors, the G1.0 PAMAM functionalized microgels exhibit high selectivity for glucose over various kinds of potential primary interferents, such as lactate, human serum albumin and metal ions, in the physiologically important glucose concentration range. Compared to traditional fluorescent dyes and quantum dots, which are limited by photobleaching and toxicity, this microgel with remarkable anti-photobleaching property and low toxicity makes it possible to be used for long-term continuous glucose monitoring. Through in vivo investigations, it can be observed that G1.0 PAMAM functionalized microgels can achieve wireless transdermal detection, indicating that the fabricated microgels have potential applications as a new generation of nanobiosensors for the highly sensitive and minimally invasive continuous glucose monitoring.
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