•A novel quantitative detection of the membrane proteins on cell•The detection of PTK-7 displays a detection limit of 12 pM.•This is a universal method for ultrasensitive of embrane protein detectionRecently, membrane proteins have been considered as candidate cancer biomarkers and drug targets, due to their important roles in numerous physiological processes. Therefore, a facile, sensitive and quantitative detection of the membrane proteins is crucial for better understanding their roles in cancer cells and further validating their function in clinical research. We report a highly facile and sensitive detection method for membrane proteins on living cells in situ based on membrane protein-triggered release of cytosine (C)-rich single-stranded DNA (ssDNA) sequences, and the subsequent silver nanoclusters (AgNCs) transfer from polymer to C-rich ssDNA. The high-quantum yield and stable DNA-AgNCs allow the accurate detection of membrane proteins with facile operations and a common fluorescence spectrophotometer. The detection of protein tyrosine kinase-7 (PTK7), a membrane protein model, displays a response range from 30 pM to 2 nM with a detection limit of 12 pM. The expression of PTK7 on single Hela cell and CCRF-CEM cell was calculated to be 7.5 × 10−19 mol and 1.8 × 10−18 mol, respectively. Given the simple and facile operation of this method, this detection platform can be applied as a universal strategy for ultrasensitive detection of membrane protein on cell in situ.A strategy for membrane protein tyrosine kinase-7 in situ detection based on the protein triggered C-rich ssDNA sequence release and the silver nanoclusters transfer between the polymer template and C-rich sequence was developed. It shows a detection range from 30 pM to 2 nM with a detection limit of 12 pM. This strategy can realize quantitative detection simply and conveniently comparing with other methods which rely on complex instrumentation.Download high-res image (215KB)Download full-size image

Herein, a simple bi-photochromic molecule containing a donor–acceptor Stenhouse adduct and azobenzene moiety was synthesized. It can achieve all-photonic multimolecular logic functions and photo-printing. This molecule could provide a novel platform for exploring multifunctional molecular logic devices.

Merocyanine dyes, owing to their unique photochemical properties, are widely used to fabricate probes for the detection of biologically active small molecules and bioimaging. In this paper, merocyanine-based probes were proved of undergoing unwanted hydrolysis. To explore the strategies toward avoiding the hydrolysis, the detailed hydrolysis mechanism was first investigated, which was also confirmed by density functional theory (DFT) calculation. Then a series of merocyanine dyes were rationally designed. Influences of molecular structures of the probes, the analytical media such as pH and components of the solution on the hydrolysis were systematically studied. The experimental results suggest that merocyanine based probes with low electron density are more likely to suffer the hydrolysis, which could be exacerbated by the well-accepted strategy for constructing type-II probes. It is worth noting that chemical surroundings could also exert distinctive influence on the hydrolysis. The hydrolysis could be obviously aggravated when fetal calf serum or DMSO was deployed. Our findings will definitely provide an effective and reliable approach for guiding the rational design of highly robust merocyanine-based probes and the optimization of the analytical media, which is helpful in terms of avoiding the hydrolysis of the probes and hydrolysis caused analytical errors.

In this study, we developed an effective approach for increasing the equilibrium adsorption capacity of the interpenetrating polymer networks (IPNs) toward polar aromatic compounds. For this purpose, a novel post-cross-linked polystyrene/poly (methyl acryloyl diethylenetriamine) (CMPS_pc/PMADETA) IPNs was synthesized and its adsorption was evaluated from aqueous solution using p-hydroxybenzoic acid as the adsorbate. CMPS_pc/PMADETA IPNs possessed a relatively high Brunauer–Emmett–Teller (BET) surface area and hydrophobic networks as well as hydrophilic networks, inducing a much enhanced adsorption toward p-hydroxybenzoic acid. The equilibrium adsorption capacity of p-hydroxybenzoic acid on CMPS_pc/PMADETA IPNs was remarkably larger than that on its precursors and the equilibrium data were correlated better by Sips model than the Langmuir and Freundlich models. Furthermore, the adsorption was a fast process, and the micropore diffusion model characterized the kinetic data very well. At a feed concentration of 1060.8 mg/L and a flow rate of 10.8 BV/h, the dynamic adsorption capacity was calculated to be 200.8 mg/mL wet resin.The CMPS_pc/PMADETA IPNs had a relatively enhanced adsorption to p-hydroxybenzoic acid.

Lithium–sulphur (Li–S) batteries with high theoretical energy densities are regarded as promising energy storage devices for electric vehicles and large-scale electricity storage. We report a facile, environment friendly, soft approach and scalable synthesis of a sulfur/graphene/multiwalled carbon nanotube (S/GN/MWCNTs) composite as a cathode for Li–S batteries by a one-pot hydrothermal method. The 2D graphene nanosheets and 1D carbon nanotubes have been chosen as a scaffold because of their conductive carbon skeleton and high specific surface area. In the composite, the carbon nanotubes can not only significantly enhance the conductivity, but also effectively tune the mesoporous structure. The as-prepared S/GN/MWCNTs hybrid electrode delivers an initial discharge capacity of 1135.9 mA h g−1 at 0.2C. Moreover, at a high current rate of 0.8C, it exhibits excellent cyclability and coulombic efficiency, the reversible charge capacity stays at 702.3 mA h g−1 after 100 cycles and the coulombic efficiency is up to 96.3%. The results confirm that the one-pot hydrothermal method is a promising approach for the synthesis of composite for lithium–sulfur batteries.

Novel hyper-cross-linked polystyrene/polyacryldiethylenetriamine (HCP/PADETA) interpenetrating polymer networks (IPNs) were prepared, characterized and evaluated for their adsorption and separation properties using hyper-cross-linked polystyrene (HCP) as the reference. In spite of its much lower Brunauer–Emmett–Teller surface area and less pore volume, HCP/PADETA IPNs possessed a preferable pore structure and appropriate polarity, resulting in a larger equilibrium capacity, faster adsorption rate, higher dynamic breakthrough and saturated capacity towards salicylic acid than HCP. In particular, HCP/PADETA IPNs had a higher enrichment factor for salicylic acid over phenol, leading to the high-efficiency separation of salicylic acid from phenol in their mixed solution.

•Succinylation of camphor leaf was conducted for sorption of Pb(II) ion.•The adsorbent was characterized by COD, FTIR, XRD and SEM.•Sorption process follows pseudo-second order model and Langmuir model.•The removal rate and sorption capacity reach 99.98% and 185.2 mg g−1.•Ion exchange mechanism was determined in the sorption process.Camphor leaf from a native everygreen tree (Cinnamomum camphora) widely distributed in southwestern part of China is locally available waste in China. A novel biosorbent (SCLP) was prepared by modification camphor leaf with succinic anhydride for Pb (II) removal. SCLP was characterized by Fourier transform infrared spectrum (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Chemical modification reduces negative effects on the treated water, and it introduces carboxyl groups on the surface, improving the sorption capacity. Sorption of Pb (II) ions was evaluated at different SCLP dose, pH, contact time and initial concentration. Sorption equilibrium and kinetics were investigated by sorption isotherms and kinetic models. Sorption of Pb (II) onto SCLP follows pseudo-second order kinetics and Langmuir model. Ion exchange plays an important role for Pb (II) uptake onto SCLP. The removal rate and sorption capacity is up to 99.98% and 185.2 mg g−1. It is anticipated that camphor leaf would find important application in purification Pb (II) from wastewaters, owing to the advantages of high efficiency, low cost and environmental friendliness.

Glycoproteins are important biomarkers and therapeutic targets in clinical diagnostics. The conventional analytical methods for glycoprotein are usually faced with some challenges, such as the complex pretreatment of samples, poor availability, and limited stability of antibody, making them not suitable for point-of-care and on-site application. Herein, we demonstrate a novel miniaturized biofuel cells (BFCs)-based self-powered nanosensor for the specific and sensitive determination of glycoproteins in complex samples through the combination of boronate-affinity molecularly imprinted polymer (MIP) and the boronate affinity functionalized biliroxidase–carbon nanotube nanocomposites. The above MIP and the nanocomposites act as both signal probe and biocatalyst at the cathode. The as-obtained self-powered MIP–BFC-based biosensor can detect horseradish peroxidase (a type of glycoprotein) with a wide linear range of 1 ng/mL to 10 μg/mL and a very low detection limit of 1 ng/mL. Especially, it shows high tolerance for different interferences (e.g., sugars and other glycoproteins) and can even measure the α-fetoprotein level in serum samples. Moreover, it exhibits significant advantages over the conventional assays in terms of cost efficiency, stability, and speed, especially inexpensive instrument needed. Our novel approach for construction of the sensor paves a simple and economical way to fabricate portable devices for point-of-care and on-site application.Keywords: biofuel cell; biosensor; glycoprotein; protein-imprinted polymer; self-power;

•We have developed a new lysosome-targeting AIE fluorescent probe TPE-MPL.•Noninvasive imaging and monitoring the morphological changes of lysosomes.•Fluorescent imaging and tracing lysosomes with high spatial and temporal resolution.We develop a new lysosome-targeting AIE fluorescent probe tetraphenylethene-morpholine (TPE-MPL), by incorporating a typical lysosome-targeting moiety of morpholine into a stable tetraphenylethene skeleton. Due to both the AIE and antenna effects, TPE-MPL possesses superior photostability, appreciable tolerance to microenvironment change and high lysosome targeting ability. Our findings confirm that TPE-MPL is a well-suited imaging agent for targeting lysosome and tracking dynamic movement of lysosome. Moreover, due to its synthetic accessibility, TPE-MPL could be further modified as a dual-functional probe for lysosome, thereby gain further insight into the role of lysosome in biomedical applications.A novel lysosome-targetable AIE fluorescent probe TPE-MPL with high photostability, appreciable tolerance to microenvironment change and high lysosome targeting properties was developed. It can be used for noninvasive imaging of lysosomes and tracking the dynamic movements of lysosomes with high spatial and temporal resolution and can track lysosomes morphology in cell apoptosis.

Proteins were proved to be type-independent templates for the biomineralization of iron ions into hematite mesocrystals with tunable structures and morphologies under hydrothemal conditions. Our finding could pave the way for the synthesis of mesocrystals with controlled stuctures and morphologies using templates of low-cost proteins.

A NIR light induced H2S release platform based on UCNPs was constructed. Under NIR light excitation, UCNPs can emit UV light which triggers H2S release in a spatial and temporal pattern. The platform was also employed to real-time monitor the delivery process in vivo, which may provide a new way for the use of H2S-based therapeutics for a variety of diseases.

•A three layered Al2O3/LixV2O5/LiV3O8 nanostructure is well formed.•The hybrid demonstrates excellent cycling stability.•The reasons for the outstanding electrochemical properties are well discussed by XRD and CV.Al2O3 coating is utilized in this work to further improve the cycling stability of LiV3O8 nanoflakes. Surprisingly, three layered Al2O3/LixV2O5/LiV3O8 nanostructure is well formed as confirmed by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) results. When used as a cathode for Li-ion battery, the hybrid demonstrates significantly improved cycling stability with a discharge capacity of 203 mAh g−1 remaining after 200 cycles at 150 mA g−1 and 87.5% of the initial capacity maintaining after 500 cycles at 300 mA g−1. Such superior cycling performance should be attributed to the mutual protection of Al2O3 and LixV2O5 layer between Al2O3 and LiV3O8, which can well suppress the damage of LiV3O8 during the long-term cycling process. More importantly, the LixV2O5 middle layer could contribute to the improvement of interfacial electrochemical properties of the hybrid electrode.

A novel polar modified post-cross-linked resin PDMPA was synthesized, characterized and evaluated for adsorption of salicylic acid from aqueous solution. PDMPA was prepared by a suspension polymerization of methyl acrylate (MA) and divinylbenzene (DVB), a Friedel–Crafts reaction and an amination reaction. After characterization of the chemical and pore structure of PDMPA, the adsorption behaviors of salicylic acid on PDMPA were determined in comparison with the precursor resins. The equilibrium adsorption capacity of salicylic acid on PDMPA was much larger than the precursor resins and the equilibrium data were correlated by both of the Langmuir and Freundlich models. The pseudo-second-order rate equation fitted the kinetic data better than the pseudo-first-order rate equation, and the micropore diffusion model could characterize the kinetic data very well. The dynamic experimental results showed that the breakthrough point and saturated point of salicylic acid on PDMPA were 40.3 and 92.4 BV (1 BV = 10 mL) at a feed concentration of 995.8 mg/L and a flow rate of 1.4 mL/min, and the resin column could be regenerated by 16.0 BV of a mixture desorption solvent containing 0.01 mol/L of NaOH (w/v) and 50% of ethanol (v/v).

•Hierarchical hybrid film of MNPs/MWFNTs–GS has been prepared.•MWFNTs are a crucial factor to form hierarchical film structure.•MWFNTs provide extra transfer paths and inhibit the aggregation of GS and MNPs.•MNPs/MWFNTs–GS show satisfying performance for the sensing detection of H2O2.Hierarchical hybrid films of MnO2 nanoparticles/multi-walled fullerene nanotubes–graphene (MNPs/MWFNTs–GS) have been prepared via a simple wet-chemical method. For this purpose, MWFNTs (~300 nm in length) are fabricated from tailoring multi-walled carbon nanotubes (MWCNTs), and then inserted into GS to pile up into a hierarchical hybrid film with the in situ formative MNPs. Scanning electron microscope, transmission electron microscope and X-ray diffraction are used to confirm the morphology and structure of the as-obtained film. The electrochemical studies reveal that MNPs/MWFNTs–GS exhibit significantly enhanced electrocatalytic activity compared with MNPs/GS, and show a rapid response to H2O2 over a wide linear range of 2.0 μM–8.44 mM with a high sensitivity of 206.3 μA mM−1 cm−2 and an excellent selectivity. These favorable electrochemical detection properties may be mainly attributed to the introduction of MWFNTs, which helps to promote the electron/ion transport between MNPs and GS and form the hierarchical film structure.

The cross-linked MnO2 nanowire (MNWS) network bridged with small-sized graphene (SSGS) with a uniform size of ~200 nm is prepared by a one-pot green hydrothermal route from graphene oxide sol and KMnO4. The route causes KMnO4 to react and form MnOx through both self-decomposition and etching graphene, as a result that MnOx grow into nanowires and micrometer-scale graphene is cut into SSGS simultaneously. The as-prepared MNWS/SSGS is characterized by scanning electron microscope, transmission electron microscope and X-ray diffractometer. The electrocatalytic activity of MNWS/SSGS for H2O2 reduction is studied by means of cyclic voltammetry and chronoamperometry. The MNWS/SSGS modified glassy carbon electrode exhibits a sensitive and prompt amperometric response to H2O2, with a sensitivity of 56 μA mM−1 and detection limit as low as 0.54 μM. These outstanding performances demonstrate that MNWS/SSGS is promising for fabrication of electrochemical sensors. Importantly, this study may offer a novel and insightful approach for the preparation and development of advanced materials based on the bridging architecture.

A peptide nanosphere-based colorimetric aptasensor for the ultrasensitive detection of adenosine triphosphate (ATP) has been fabricated. By conjugating gold nanoparticles (AuNPs) onto peptide nanospheres (PNS), the PNS/AuNPs nanocomposite was obtained and used as a carrier for single-strand ATP aptamer (S1) and signaling DNAzyme sequence. In the presence of ATP, the nucleic acids decorated PNS/AuNPs could immobilize to a 96-well plate which was modified with another single-strand ATP aptamer (S2) DNA. Then, upon addition of K+ and hemin, the designed signaling DNAzyme sequence on PNS/AuNPs could form the hemin–G-quadruplex DNAzyme and catalyze the conversion of TMB to coloured TMB2+. The colorimetric aptasensor adopting PNS/AuNPs nanocomposites as signal enhancers possesses much higher sensitivity towards ATP compared with the conventional AuNPs-based aptasensors. The PNS/AuNPs-based sensor is available for sensitively detecting ATP in a concentration range of 0.01–1 nM with a detection limit of 1.35 pM. Moreover, the constructed aptasensor displayed excellent selectivity for ATP over other analogues such as GTP, CTP and UTP. The proposed strategy for the construction of an aptasensor based on nanocomposites has great potential to become a universal technique for developing various aptasensors by using different aptamers.

In this work, carboxymethyl dextran (CMD), a polysaccharidic dextran derivative with well-known biocompatibility and biodegradability, was used to modify curcumin-loaded liposomes for improving the anticancer efficacy of curcumin. The CMDylated curcumin-loaded liposomes (CMD-Cur-Lip) were successfully prepared and characterized in comparison with unmodified and two PEGylated curcumin-loaded liposomes. The results showed that: (1) the encapsulation efficiency of curcumin in the liposomes was improved after being modified with CMD; (2) all the curcumin-loaded liposomes displayed controlled release characteristics; (3) the CMD-Cur-Lip demonstrated improved cell cytotoxicity against cancer cells, as compared to other liposomal formulations and free curcumin; (4) CMD-Cur-Lip exhibited the highest cellular uptake as compared to other liposomal formulations.

A naphthalimide-based azo dye (1) used as a colorimetric and ratiometric probe for the detection of CN− was synthesized by incorporating a salicylaldehyde moiety, which acts as a recognition unit, to the naphthalimido diazonium salt. Upon reacting with CN−, probe 1 displays dramatic colour changes rapidly from yellowish to red, corresponding to the absorption band shift from 408 nm to 497 nm. The colorimetric probe allows ratiometric detection of CN− with a linear range of 2–45 μM and a LOD (limit of detection) of 0.4 μM. In the optimized H2O/DMSO (7/3, v/v) mixed solvent, probe 1 displays excellent selectivity for CN− over other anions. In addition, 1 was successfully employed to prepare the filter paper-based test strips which can be used to monitor CN− conveniently, and the discernible concentration of CN− can be as low as 20 μM.

•Uniform polyaniline (PANI) nanowire was prepared by using peptide assembled fibers as the template.•A novel electrochemical biosensor was constructed based on the high electrochemical activity of the PANI nanowire.•The biosensor displayed high sensitivity and selectivity for hepatitis B virus gene.A novel electrochemical active polyaniline (PANI) nanowire was fabricated and utilized for the construction of a highly sensitive and selective electrochemical sensor for hepatitis B virus gene. The uniform PANI nanowire was prepared by the enzymatic polymerization of aniline monomers on the amyloid-like nanofiber (AP nanowire), which was self-assembled from an aniline-attached nonapeptide, aniline-GGAAKLVFF (AP). The prepared PANI nanowires were characterized by electron microscopy, UV–vis absorption spectra, and cyclic voltammetry (CV). These ultra-thin nanowires displayed high electrochemical activity. Then the nucleic acid biosensor was constructed by modifying a glass carbon electrode with AP nanowires which were functionalized by a designed hair-pin loop DNA. Upon the presence of target nucleic acid and horseradish peroxidase (HRP) labeled oligonucleotide, the HRP will catalyze the polymerization of aniline monomers conjugated in AP nanowires, leading to the formation of PANI nanowires which can bring about a dramatical increase in the current response of the biosensor. The dynamic range of the sensor for hepatitis B virus gene is 2.0–800.0 fM with a low detection limit of 1.0 fM (3σ, n=10). The biosensor also displayed highly selectivity and stability. All these excellent performances of the developed biosensor indicate that this platform can be easily extended to the detection of other nucleic acids.

•We prepared imprinted-like biopolymeric micelles (IBMs) via green process.•IBMs showed imprinted-like property for the polyphenol analogous drugs.•Water solubility of curcumin was increased by 5 × 104-fold after encapsulation.•Curcumin-loaded IBMs exhibited superior growth inhibition against tumor cells.•IBMs could effectively improve the oral bioavailability of curcumin.To enhance the solubility and improve the bioavailability of hydrophobic curcumin, a new kind of imprinted-like biopolymeric micelles (IBMs) was designed. The IBMs were prepared via co-assembly of gelatin–dextran conjugates with hydrophilic tea polyphenol, then crosslinking the assembled micelles and finally removing the template tea polyphenol by dialysis. The obtained IBMs show selective binding for polyphenol analogous drugs over other drugs. Furthermore, curcumin can be effectively encapsulated into the IBMs with 5 × 104-fold enhancement of aqueous solubility. We observed the sustained drug release behavior from the curcumin-loaded IBMs (CUR@IBMs) in typical biological buffers. In addition, we found the cell uptake of CUR@IBMs is much higher than that of free curcumin. The cell cytotoxicity results illustrated that CUR@IBMs can improve the growth inhibition of HeLa cells compared with free curcumin, while the blank IBMs have little cytotoxicity. The in vivo animal study demonstrated that the IBMs could significantly improve the oral bioavailability of curcumin.

We developed a pH-dependent etching method for the synthesis of stable fluorescent silver nanoclusters (AgNCs) in aqueous solution. The AgNCs emit at 530 nm when excited at 380 nm and can be used for Hg2+ detection with a low detection limit and high selectivity.

An aniline–GGAAKLVFF peptide (AFP) was prepared by solid-phase synthesis. The peptide can readily self-assemble into fibrils. Platinum nanoparticles (Pt NPs) were directly immobilized on the surface of the AFP fibrils via electrostatic interaction. Compared to other currently available techniques for the fabrication of metal–peptide fibrils, the noncovalent functionalization strategy is able to deposit nanoparticles on peptide fibrils with different morphologies and high metal loading, which is important for applications in catalysis, electronic materials and other corresponding fields. The Pt–AFP fibrils were employed to modify the electrode, which exhibits high electrocatalytic activities towards oxygen reduction. Thus, the Pt–AFP fibrils hold great potential for polymer electrolyte fuel cells and other electrochemical applications.

•Hierarchical dumbbell-shaped LiFePO4 mesocrystals were fabricated without any additive.•Co-solvent of DMF/EG was applied for the solvothermal synthesis of cathode materials.•The DMF/EG co-solvent played a crucial role in the formation of dumbbell-shaped LFP mesocrystals.•The formation of the LFP mesocrystals was possibly following a two-step process.•The LFP/C mesocrystals show better storage performance at higher rate after in-situ carbon coated.Hierarchical dumbbell-shaped lithium iron phosphate (LiFePO4) mesocrystals were successfully fabricated via a simple one-step, rapid, additive-free solvothermal route. A mixture of dimethylformamide/ethylene glycol (DMF/EG) has been utilized as the co-solvent and found to play an important role in the formation of the hierarchical mesostructure. The obtained dumbbell-shaped mesocrystals consist of self-assembly LiFePO4 nanorods each with 2–3 μm in length and 30–50 nm in diameter. Further temperature treatment was applied to increase the crystallinity of the LiFePO4 mesocrystals. A high lithium ion intercalation capacity of 140 mA h g−1 was exhibited by the LiFePO4 mesocrystal when tested under a discharge rate of 17 mA g−1, which should be attributed to the fast intercalation reaction and easy mass and charge transfer offered by the large specific surface and short diffusion distance of dumbbell-shaped mesoporous composed of nano-sized LiFePO4 rods. The nanorods can be carbon coated in-situ by adding sucrose during the solvothermal process and the LiFePO4/C mesocrystals showed an improved electrochemical property at higher rates and good cyclic performance.

Three new hydroxyl-substituted Schiff-bases containing ferrocenyl moieties were synthesized, and their antioxidant and anticancer activities were evaluated. Among the synthesized hydroxyl-substituted Schiff-bases, compound 1 containing both ferrocenyl and o-dihydroxyl groups exhibits the highest antioxidant and anticancer activities. Flow cytometric analysis showed that compound 1 is capable of disturbing the cancer cell cycle and inducing more cells to be arrested in G2 phase. The excellent biological activities of compound 1 are attributed to the presence of both ferrocenyl and o-dihydroxyl groups. The ferrocenyl moiety has dual functions in compound 1, i.e., increasing the lipophilicity and lowering the redox potentials of o-dihydroxyl groups. In addition, compound 1 could reversibly bind with HSA mainly via a mechanism involving the formation of complexes, in which hydrophobic interaction is the main acting force. Thus, compound 1 containing both ferrocenyl and o-dihydroxyl groups is a potential antioxidant with anticancer activity.

The intracellular α-synuclein (α-syn) protein, whose conformational change and aggregation have been closely linked to the pathology of Parkingson's disease (PD), is highly populated at the presynaptic termini and remains there in the α-helical conformation. In this study, circular dichroism confirmed that natively unstructured α-syn in aqueous solution was transformed to its α-helical conformation upon addition of trifluoroethanol (TFE). Electrochemical and UV–visible spectroscopic experiments reveal that both Cu (I) and Cu (II) are stabilized, with the former being stabilized by about two orders of magnitude. Compared to unstructured α-syn (Binolfi et al., J. Am. Chem. Soc. 133 (2011) 194–196), α-helical α-syn stabilizes Cu (I) by more than three orders of magnitude. Through the measurements of H2O2 and hydroxyl radicals (OH) in solutions containing different forms of Cu (II) (free and complexed by unstructured or α-helical α-syn), we demonstrate that the significantly enhanced Cu (I) binding affinity helps inhibit the production of highly toxic reactive oxygen species, especially the hydroxyl radicals. Our study provides strong evidence that, as a possible means to prevent neuronal cell damage, conversion of the natively unstructured α-syn to its α-helical conformation in vivo could significantly attenuate the copper-modulated ROS production.α-Helical α-synuclein significantly stabilizes Cu (I), attenuating the production of reactive oxygen species.Highlights► Both Cu (I) and Cu (II) are strongly coordinated by α-helical α-syn. ► α-Helical α-syn stabilizes Cu (I) 104 time more than unstructured α-syn does. ► Stabilization of Cu (I) by α-helical α-syn leads to a controlled production of H2O2. ► OH production via copper redox cycling is attenuated by Cu (I) coordination with α-syn.

A novel ratiometric fluorescent probe A1, based on excited-state intramolecular proton transfer (ESIPT) mechanism, for the detection of benzoyl peroxide (BPO) was designed and synthesized. A1 was employed for determining BPO in food and pharmaceutical samples with good sensitivity and high selectivity.

Alzheimer’s disease (AD) is the most common cause of dementia, and currently there is no clinical treatment to cure it or to halt its progression. Aggregation and fibril formation of β-amyloid peptides (Aβ) are central events in the pathogenesis of AD. Many efforts have been spent on the development of effective inhibitors to prevent Aβ fibrillogenesis and cause disaggregation of preformed Aβ fibrils. In this study, the conjugates of ferrocene and Gly-Pro-Arg (GPR) tripeptide, Boc-Gly-Pro-Arg(NO2)-Fca-OMe (4, GPR–Fca) and Fc-Gly-Pro-Arg-OMe (7, Fc–GPR) (Fc: ferrocene; Fca: ferrocene amino acid) were synthesized by HOBT/HBTU protocol in solution. These ferrocene GPR conjugates were employed to inhibit Aβ1–42 fibrillogenesis and to disaggregate preformed Aβ fibrils. The inhibitory properties of ferrocene GPR conjugates on Aβ1–42 fibrillogenesis were evaluated by thioflavin T (ThT) fluorescence assay, and confirmed by atomic force microscopy (AFM) analysis. The interaction between the ferrocene GPR conjugates and Aβ1–42 was monitored by electrochemical means. Our results showed that both GPR and GPR–Fca can significantly inhibit the fibril formation of Aβ1–42, and cause disaggregation of the preformed fibrils. As expected, GPR–Fca shows stronger inhibitory effect on Aβ1–42 fibrillogenesis than that of its parent peptide GPR. In contrast, Fc–GPR shows no inhibitory effect on fibrillogenesis of Aβ1–42. Furthermore, GPR–Fca demonstrates significantly protection against Aβ-induced cytotoxicity and exhibits high resistance to proteolysis and good lipophilicity.The ferrocene GPR conjugates were synthesized in solution. GPR–Fca shows stronger inhibitory effect on Aβ1–42 fibrillogenesis and disaggregation of existing Aβ1–42 mature fibrils. Moreover, GPR–Fca demonstrates significant protection against Aβ-induced cytotoxicity and high resistance to proteolysis.

The aggregation of amyloidogenic proteins/peptides has been closely linked to the neuropathology of several important neurological disorders. In Alzheimer’s disease, amyloid beta (Aβ) peptides and their aggregation are believed to be at least partially responsible for the etiology of Alzheimer’s disease. The aggregate-inflicted cellular toxicity can be inhibited by short peptides whose sequences are homologous to segments of the Aβ(1–42) peptide responsible for β-sheet stacking (referred to as the β-sheet breaker peptides). Here, a water-soluble ferrocene (Fc)-tagged β-sheet breaker peptide, Fc-KLVFFK6, was used as an electrochemical probe for kinetic studies of the inhibition of the Aβ(1–42) fibrillation process and for determination of the optimal concentration of β-sheet breaker peptide for efficient inhibition. Our results demonstrate that Fc-KLVFFK6 interacts with the Aβ aggregates instantaneously in solution, and a sub-stoichiometric amount of Fc-KLVFFK6 is sufficient to inhibit the formation of the Aβ oligomers and fibrils and to reduce the toxicity of Aβ(1–42). The interaction between Fc-KLVFFK6 and Aβ(1–42) follows a pseudo-first-order reaction, with a rate constant of 1.89 ± 0.05 × 10−4 s−1. Tagging β-sheet breaker peptides with a redox label facilitates design, screening, and rational use of peptidic inhibitors for impeding/altering Aβ aggregation.

A novel disposable biosensor containing a detection electrode and a control electrode was constructed by the screen-printing techniques. The detection electrode was covered with the enzyme ink to measure the oxidation currents of the catalytic substrate, while the control electrode was coated with non-enzyme ink to monitor the interference signals. The net catalytic currents of the enzyme electrode can be obtained from the response differences of the two recording electrodes. The biosensor for detection of glucose in blood sample showed a good linear relationship in the range of 0.5–50 mM (R = 0.9986) with a detection limit of 0.05 mM (S/N = 3), and displayed a high selectivity. The general applicability of the biosensor was demonstrated by successfully using it for detecting uric acid in blood sample. The proposed biosensor possesses a high selectivity and accuracy for detecting species in biological samples, which opens the possibility of developing screen-printed electrode-based devices for bioanalysis.

•N3 dye was firstly used as a chromophore in a colorimetric competition assay.•A strategy based on a competitive ligation of Hg2+ by –SH and –SCN was proposed.•The new method can be successfully employed to detect Cys and GSH.A novel reversible colorimetric sensor, which based on a competitive ligation of Hg2+ by thiols, cysteine (Cys) or glutathione (GSH), and thiocyanate (SCN) on the N3 dye (bis(4,4′-dicarboxy-2,2′-bipyridine) dithiocyanato ruthenium (II)), was developed for the detection of biothiols. First, Hg2+ ions coordinate to the sulfur atom of the dyes' SCN groups, and this interaction induces a change in color from red to yellow, owing to the formation of a complex of Hg2+–N3. Then, in the presence of biothiols, the red color of N3 is recovered concomitantly with the dissociation of the Hg2+–N3 complex, due to the extraction of Hg2+ by biothiols. Thus the corresponding color variation in the process of the dissociation of the Hg2+–N3 complex can be employed for the quantitative detection of thiols using UV–vis spectroscopy. In particular, the transformation can be readily viewed with the naked eye. A good linear relationship between the change in absorbance (ΔAbs) of Hg2+–N3 at 461 nm and the thiol concentration was obtained in the range of 0.5–25 μM, and the detection limits are then calculated to be 57 and 52 nM for Cys and GSH, respectively. The proposed colorimetric assay displays a high selectivity for Cys over various other amino acids and GSSG (oxidized glutathione).

A porous reticulated vitreous carbon (RVC) electrode and a disk electrode coupled in tandem in an electrochemical flow cell has been used for electrolytic removal of interferents before amperometric glucose detection. The electrolytic efficiency at the upstream RVC electrode is 100% at a flow rate of 0.1 mL min−1 or lower. Potential interferents such as acetaminophen, ascorbic acid, and uric acid can be completely eliminated by electrolysis at the RVC electrode. A mixed monolayer comprising glucose oxidase (GOD) and ferrocenyl-1-undecanethiol preformed at the downstream gold disk electrode was used as a mediator-based amperometric glucose sensor. The dependence of the amperometric current on the glucose concentration exhibits good linearity across over three orders of magnitude. The glucose measurements were also found to be reproducible (RSD < 3.5%) and accurate. Unlike the chemiluminescence method, this device obviates the use of carcinogenic substrates and the glucose sensor performance is independent of the oxygen present in sample. On the basis that the RVC electrode requires minimal cleanup and the GOD-modified electrode remains stable for a week, the electrochemical flow cell should be amenable for automated on-line removal of redox interferents for other types of enzyme-based biosensors.Graphical abstractHighlights► The electrochemical glucose detection was carried out based on an electrochemical flow cell comprising a porous reticulated vitreous carbon (RVC) electrode and a disk electrode. ► The design is much simpler and easier to implement for real sample assays. ► The RVC electrode requires minimal cleanup and the GOD-modified electrode remains stable for a week. ► The electrochemical flow cell should be amenable for automated on-line removal of redox interferents for other types of enzyme-based biosensors.

Ferrocene (Fc) and its conjugates have attracted considerable attention in recent years due to their unique electrochemical behavior and significant biological activities such as antitumor, antimalarial, and antifungal. Arg-Gly-Asp (RGD)-containing peptides, because of their selective binding to integrins which are highly expressed in tumor-induced angiogenesis, play a key role in cancer targeted therapy. In this study, Fc–RGD and Fc–Am–RGD (Fc: ferrocenoyl; Am: 6-aminohexanoic acid) conjugates were synthesized, and the antitumor activities in vitro were investigated. The cell uptake of the conjugates by B16 murine melanoma cells was measured using HPLC-electrochemical method. The antitumor activities of the conjugates were also evaluated by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) and flow cytometric measurements. The experimental results revealed that Fc–RGD and Fc–Am–RGD exhibit more effective antitumor activities than their parent compounds RGD and Fc-COOH. Moreover, it is found that Fc–Am–RGD yields the lowest IC50 values of 5.2 ± 1.4 μM toward B16 cells. The HPLC-electrochemical studies confirmed that the insertion of flexible alkyl spacer Am between Fc and RGD significantly increases the cell uptake toward B16 cells and consequently improves the antitumor activity. Our results suggest that Fc–RGD and Fc–Am–RGD conjugates are potential candidates for cancer treatment.The ferrocene-conjugated Arg-Gly-Asp peptides were synthesized in solution. The cell uptake of the ferrocenoyl conjugates was tested by HPLC-electrochemical method. Fc–Am–RGD shows higher cell uptake and antitumor activity than its parent compound Fc-COOH due to the attachment of RGD and insertion of flexible alkyl spacer between ferrocene and RGD.Highlights► Ferrocene-conjugated Arg-Gly-Asp peptides were synthesized in solution. ► Cell uptake of the ferrocenoyl conjugates was tested by HPLC-electrochemical method. ► Fc–Am–RGD shows much higher antitumor activity than Fc-COOH. ► The flexible alkyl spacer between ferrocene and RGD enhances the cell uptake.

To develop a novel and low-cost membrane as a separator of vanadium redox flow battery, sulfonated poly(phthalazinone ether sulfone) (SPPES) was prepared by sulfonating PPES with fuming sulfuric acid. By testing the sulfonation degree, intrinsic viscosity, and solubility of SPPES, the results showed that sulfonated polymers had higher intrinsic viscosities and excellent solubility in most polar solvents. IR analysis revealed that the –SO3H group was successfully attached to SPPES backbone. DSC and TG results showed that SPPES exhibited higher Tg than that of PPES, and Td at the first weight loss of SPPES was about 300 °C. The SPPES membrane (SP-02) showed a dramatic reduction in crossover of vanadium ions across the membrane compared with that of the Nafion membrane. Cell tests identified that VRB with the SPPES membrane exhibited a lower self-discharge rate, higher coulombic efficiency (92.82%), and higher energy efficiency (67.58%) compared with the Nafion system. Furthermore, cycling tests indicated that the single cell with SPPES membrane exhibited a stable performance during 100 cycles.

Nanoencapsulation is a promising method to improve the bioavailability of tea polyphenol (TPP). In this work, we adopted a green process to develop a new kind of complex coacervation core micelles (C3Ms) based on biopolymers for efficient tea polyphenol delivery. First, gelatin–dextran conjugate was synthesized using Maillard reaction. Then the C3Ms were produced by mixing gelatin–dextran conjugate with TPP. Variable factors on the self-assembly of the C3Ms were investigated. Under optimal conditions, the obtained C3Ms are of nanosize (average 86 nm in diameter) with narrow distribution. The formation of the C3Ms is attributed to hydrophobic interaction and hydrogen bonding instead of electrostatic interaction. Transmission electron microscope (TEM) and scanning electron microscope (SEM) results showed that C3Ms have a spherical shape with core–shell structure. ζ-Potential measurement suggested that the core is composed of gelatin with TPP, whereas the shell is composed of dextran segments. The encapsulation efficiency of the C3Ms is pH-independent, but the loading capacity is controllable and as high as 360 wt % (weight/weight of protein). In addition, the C3Ms show sustained release of TPP in vitro. MTT assay revealed that the C3Ms have comparable or even stronger cytotoxicity against MCF-7 cells than free TPP.

This paper describes the fabrication and application of a complex electrode – Nafion film coating ferrocenylalkanethiol (FcC11SH) and encapsulated glucose oxidase (GOD) on a gold electrode. FcC11SH is employed as a mediator enabling the electron transfer between GOD and the electrode, GOD is encapsulated in polyacrylamide gel to improve the stability of the enzyme, and the Nafion film is coated on the modified electrode to eliminate interferents such as ascorbic acid, uric acid and acetaminophen in amperometric glucose detection. It is noticed that such a complex electrode exhibits excellent catalytic activity for glucose oxidation, and preserves the native structure of GOD and therefore its enzymatic activity. The encapsulated GOD retains more than 80% of its original biocatalytic activity even after 24 days, much longer than that of naked GOD molecules attached directly to the electrode. The oxidation peak current at the modified electrode shows a linear relationship with the glucose concentration in the range from 0.05 to 20 mM with a detection limit of 2.4 μM. In addition, the electrode displays a rapid response and good reproducibility for glucose detection, and has been successfully employed for glucose detection in blood plasma samples.

Liposomes have been widely used as promising drug delivery systems. The stabilization of liposomes however remains challenging, especially when surface binding properties are involved. In this work, we reported carboxymethyl dextran-coated liposomes (CMD-LIPs), in an attempt to improve their stability, surface binding and release properties. Firstly, we introduced hydrophobic oleyl groups onto CMD, and then used the amphiphilic CMD, phosphatidylcholine and cholesterol to prepare the CMD-LIPs. Surface plasmon resonance measurements confirmed that CMD-LIPs inhibited non-specific protein adsorption and exhibited active targeting when coupling ligands to the liposomal surface. Moreover, doxorubicin (DOX)-loaded CMD-LIPs displayed a sustained and pH-responsive drug release profile. MTT assay revealed that the cytotoxicity of DOX-loaded CMD-LIPs on HeLa cells was time- and concentration- dependent. Additionally, the DOX-loaded CMD-LIPs were highly stable in serum media and against dilution, long-term storage and lyophilization.

•Flotation separation of plastics was reviewed including principles, methods and challenges.•The specific features of plastics flotation are presented compared to ores flotation.•Four methods were classified in terms of plastics flotation.•The problems that hinder the application of plastics flotation are put forward.The sharp increase of plastic wastes results in great social and environmental pressures, and recycling, as an effective way currently available to reduce the negative impacts of plastic wastes, represents one of the most dynamic areas in the plastics industry today. Froth flotation is a promising method to solve the key problem of recycling process, namely separation of plastic mixtures. This review surveys recent literature on plastics flotation, focusing on specific features compared to ores flotation, strategies, methods and principles, flotation equipments, and current challenges. In terms of separation methods, plastics flotation is divided into gamma flotation, adsorption of reagents, surface modification and physical regulation.

•The EDLVO profiles were calculated to examine interparticle interactions.•The dominant force between plastic particles is hydrophobic attraction.•Selective adsorption of wetting agents improves flotation separation of plastics.•Increasing the polarity of solid surface reduces hydrophobic attraction.Plastics flotation used for recycling of plastic wastes receives increasing attention for its industrial application. In order to study the mechanism of plastics flotation, the interfacial interactions between plastic particles in flotation system were investigated through calculation of Lifshitz–van der Waals (LW) function, Lewis acid–base (AB) Gibbs function, and the extended Derjaguin–Landau–Verwey–Overbeek potential energy profiles. The results showed that van der Waals force between plastic particles is attraction force in flotation system. The large hydrophobic attraction, caused by the AB Gibbs function, is the dominant interparticle force. Wetting agents present significant effects on the interfacial interactions between plastic particles. It is found that adsorption of wetting agents promotes dispersion of plastic particles and decreases the floatability. Pneumatic flotation may improve the recovery and purity of separated plastics through selective adsorption of wetting agents on plastic surface. The relationships between hydrophobic attraction and surface properties were also examined. It is revealed that there exists a three-order polynomial relationship between the AB Gibbs function and Lewis base component. Our finding provides some insights into mechanism of plastics flotation.

•Ammonia treatment changes selectively floatability of PC.•The effects of ammonia on PC were investigated through contact angle and XPS.•Reactions between ammonia and PC surface make PC more hydrophilic.•PC and ABS mixtures with different particle sizes were separated effectively.The objective of this research is flotation separation of polycarbonate (PC) and acrylonitrile–butadiene–styrene (ABS) waste plastics combined with ammonia pretreatment. The PC and ABS plastics show similar hydrophobicity, and ammonia treatment changes selectively floatability of PC plastic while ABS is insensitive to ammonia treatment. The contact angle measurement indicates the dropping of flotation recovery of PC is ascribed to a decline of contact angle. X-ray photoelectron spectroscopy demonstrates reactions occur on PC surface, which makes PC surface more hydrophilic. Separation of PC and ABS waste plastics was conducted based on the flotation behavior of single plastic. At different temperatures, PC and ABS mixtures were separated efficiently through froth flotation with ammonia pretreatment for different time (13 min at 23 °C, 18 min at 18 °C and 30 min at 23 °C). For both PC and ABS, the purity and recovery is more than 95.31% and 95.35%, respectively; the purity of PC and ABS is up to 99.72% and 99.23%, respectively. PC and ABS mixtures with different particle sizes were separated effectively, implying that ammonia treatment possesses superior applicability.

A NIR light induced H2S release platform based on UCNPs was constructed. Under NIR light excitation, UCNPs can emit UV light which triggers H2S release in a spatial and temporal pattern. The platform was also employed to real-time monitor the delivery process in vivo, which may provide a new way for the use of H2S-based therapeutics for a variety of diseases.

Three new hydroxyl-substituted Schiff-bases containing ferrocenyl moieties were synthesized, and their antioxidant and anticancer activities were evaluated. Among the synthesized hydroxyl-substituted Schiff-bases, compound 1 containing both ferrocenyl and o-dihydroxyl groups exhibits the highest antioxidant and anticancer activities. Flow cytometric analysis showed that compound 1 is capable of disturbing the cancer cell cycle and inducing more cells to be arrested in G2 phase. The excellent biological activities of compound 1 are attributed to the presence of both ferrocenyl and o-dihydroxyl groups. The ferrocenyl moiety has dual functions in compound 1, i.e., increasing the lipophilicity and lowering the redox potentials of o-dihydroxyl groups. In addition, compound 1 could reversibly bind with HSA mainly via a mechanism involving the formation of complexes, in which hydrophobic interaction is the main acting force. Thus, compound 1 containing both ferrocenyl and o-dihydroxyl groups is a potential antioxidant with anticancer activity.

Proteins were proved to be type-independent templates for the biomineralization of iron ions into hematite mesocrystals with tunable structures and morphologies under hydrothemal conditions. Our finding could pave the way for the synthesis of mesocrystals with controlled stuctures and morphologies using templates of low-cost proteins.

A naphthalimide-based azo dye (1) used as a colorimetric and ratiometric probe for the detection of CN− was synthesized by incorporating a salicylaldehyde moiety, which acts as a recognition unit, to the naphthalimido diazonium salt. Upon reacting with CN−, probe 1 displays dramatic colour changes rapidly from yellowish to red, corresponding to the absorption band shift from 408 nm to 497 nm. The colorimetric probe allows ratiometric detection of CN− with a linear range of 2–45 μM and a LOD (limit of detection) of 0.4 μM. In the optimized H2O/DMSO (7/3, v/v) mixed solvent, probe 1 displays excellent selectivity for CN− over other anions. In addition, 1 was successfully employed to prepare the filter paper-based test strips which can be used to monitor CN− conveniently, and the discernible concentration of CN− can be as low as 20 μM.