The primary pollutant, radioactive iodine (I2), has become a worldwide concern due to its serious ill effects of radiotoxicity on human health. Therefore, it is of great significance to develop novel adsorbents for effectively eliminating I2 from nuclear waste. Herein, we reported a Zr-based MOF adsorbent constructed by utilizing pyridine-containing pyridine-dicarboxylic acid (PYDC) as organic ligands (UiO-66-PYDC) as well as active sites for the efficient removal of I2. UiO-66-PYDC MOFs were synthesized by a hydrothermal strategy and featured good chemical and thermal stabilities, endowing them with the ability to work in harsh environments. The abundant and inherent pyridine moieties in the developed adsorbent worked as active adsorption sites to capture I2. The correlation between the most significant parameters such as the contact time, adsorbate concentration, and reusability was optimized, and the interaction mechanism between I2 and UiO-66-PYDC was investigated in detail. As for the current adsorbent, a pseudo-second order rate equation was used to explain the removal kinetics, and the Langmuir model exhibited a better fit to the adsorption isotherm than the Freundlich model. Thanks to the strong affinity of PYDC ligands to I2 and high porosity, the adsorption capacities of UiO-66-PYDC for I2 could reach as high as 1250 mg g−1, which was much higher than those of many other reported MOFs. Additionally, the UiO-66-PYDC MOFs exhibited excellent renewable adsorption properties, prefiguring their great promise as green adsorbents for I2 removal in nuclear waste management.

Despite that they are regarded as the ideal sensory platform, there are still no reports on luminescent metal–organic frameworks (LMOFs) for dissolved oxygen (DO) measurement. Here, we reported the rational construction of a platinum(II) porphyrinic LMOF, PCN-224(Pt), as an novel porous matrix for the phosphorescent DO sensing with commercially available Pt(II) meso-tetra(4-carboxyphenyl)porphyrin as the bridging struts, oxygen-sensitive centers, and luminescent reporters. The newly developed probe featured excellent tolerance to harsh chemical environments, excellent photostability as well as pH-independent luminescence, rationalizing its suitability for DO sensing. Thanks to the homogeneous and well-isolated arrangement of the oxygen-accessible sites in the porous network, PCN-224(Pt) exhibited reversible phosphorescent response and excellent linear Stern–Volmer quenching behavior toward DO. A real-time analysis of DO during the process of enzyme-catalytic reaction exemplified its potentials in industrial and biological applications with oxygen involved.

Developing an effective method that could provide simple, rapid and visual determination of Hg2+ in water has attracted great attention. In this work, a novel chemical sensor with a porphyrin-based luminescent metal–organic framework (LMOFs) which exhibited a dual-mode response to trace amounts of mercury ions (Hg2+) has been successfully constructed. The porous LMOF probe was fabricated using a simple solvothermal reaction, and assembled with Zr–O clusters as inorganic nodes and meso-tetra(4-carboxyphenyl)porphyrin (TCPP) ligands as organic bridging struts. The sensing activity was realized by using the inherent TCPP struts as recognition sites and signal reporter, which presented a specific interaction with Hg2+ over other potentially interfering metallic cations. The LMOFs which were developed exhibited a visible fluorescent quenching (bright red-dark red) and a colorimetric response (purple-light green) in the presence of Hg2+ with a response rate as rapid as 2 min. Additionally, the fluorescence quenching showed a linear correlation in the Hg2+ concentration range from 0.1 to 10 μM and the limit of detection was calculated to be 6 nM, which was in agreement with the acceptable level of Hg2+ in drinking water mandated by the United States Environmental Protection Agency. Furthermore, the sensor for Hg2+ detection was reversible after the treatment with potassium iodide solution, which suggested that it has great potential as an economical alternative for practical Hg2+ quantification in water. The easily constructed sensory probe was also applied to determine the concentration of Hg2+ in tap water to demonstrate its practical applications.

Luminescent metal–organic frameworks (LMOFs) have attracted significant attention as a unique class of sensing materials. In this work, the intrinsically fluorescent amino derivative of UiO-66 (UiO-66-NH2) was successfully exploited as a fluorescent probe for the sensitive and selective detection of phosphate anions in an aqueous medium. The inorganic Zr–O clusters and organic BDC-NH2 linkers in the elaborated UiO-66-NH2 MOFs were individually designed as phosphate recognition sites and signal reporters. The intrinsic fluorescence of BDC-NH2 was tuned from high to weak emission by ligand-to-metal charge transfer (LMCT) upon its integration into the framework of UiO-66-NH2 MOFs and this weakened fluorescence could be proportionally recovered in correlation with the applied phosphate level through a newly developed competitive coordination effect. The specificity for phosphate recognition of the employed sensory platform was scarcely affected by other possible interfering species. The efficacy of this strategy was demonstrated by a linear phosphate detection range of 5–150 μM and a limit of detection of 1.25 μM, which was far below the detection requirement of phosphate discharge criteria in the water environment. The possible sensing mechanisms for anionic phosphate detection using the currently established fluorescent probe, including host–guest interaction and structure–property correlation, were systematically investigated using XPS, FT-IR, XRD, TEM and N2 sorption techniques.

The accurate characterization of low abundance phosphopeptides based on mass spectrometry (MS) techniques remains a challenge due to signal suppression by the large excess of interfering proteins and non-phosphopeptides. This demands better methods to effectively enrich phosphopeptides prior to MS analysis. In the current work, facilely synthesized Zr-based metal–organic frameworks (MOFs) of UiO-66 and UiO-67 have been successfully exploited as novel affinity materials for the enrichment and analysis of phosphopeptides. Thanks to their abundantly existent and naturally exposed Zr–O clusters, intrinsically large surface areas and highly ordered open cavities, UiO-66 and UiO-67 exhibited sensitive and specific enrichment of phosphopeptides with an interesting molecular sieving effect. An optimized protocol for loading, washing and elution was developed. Under these most optimized conditions, specific accumulation was demonstrated by the selective enrichment of phosphopeptides in the presence of abundant non-phosphorylated species. Meanwhile, high-abundance interfering proteins could be effectively excluded during the enrichment process. Additionally, the MOFs have also been successfully used to enrich phosphopeptides from human serum. These merits combined with their high chemical and thermal stabilities, make UiO-66 and UiO-67 highly promising for applications in phosphopeptidome research.

Development of a rapid and effective method for the detection of 2,4,6-trinitrotoluene (TNT) in aqueous phase has attracted great attention. In this work, the fluorescent porphyrin-based metal–organic frameworks (MOFs) of PCN-224 were successfully exploited as a fluorescent probe for the rapid and selective TNT detection in water media. This strategy combined the advantages of fluorescent porphyrin molecules and porous MOFs, which not only overcame the aggregation of hydrophobic tetrakis(4-carboxyphenyl)porphyrin (TCPP) recognition sites but also promoted TNT to interact with recognition sites in virtue of the high surface and intrinsic open structure of MOFs. As a result, a rapid response time of as short as 30 s was obtained for the elaborated fluorescent probe. Meanwhile, the bright red emission of porphyrin units in PCN-224 could be proportionally quenched in correlation with the applied TNT level through the formation of TNT-TCPP complex in the ground state. The specificity of the employed sensory platform for TNT recognition was scarcely affected by other possible coexistent interfering species. Furthermore, this fluorescent PCN-224 probe presented a much higher quenching efficiency for TNT than other structurally similar nitroaromatic compounds and was successfully applied for the quantitative detection of TNT in the mixed nitroaromatic explosive samples. This prefigured their great potentials of practical TNT detection in water media for public safety and security.Keywords: aqueous phase; fluorescent sensors; metal−organic frameworks; porphyrin; TNT detection;

Though many efforts have been devoted to the adsorptive removal of hazardous materials of organophosphorus pesticides (OPs), it is still highly desirable to develop novel adsorbents with high adsorption capacities. In the current work, the removal of two representative OPs, glyphosate (GP) and glufosinate (GF), was investigated by the exceptionally stable Zr-based MOFs of UiO-67. The abundant Zr–OH groups, resulting from the missing-linker induced terminal hydroxyl groups and the inherent bridging ones in Zr–O clusters of UiO-67 particles, served as natural anchorages for efficient GP and GF capture in relation with their high affinity toward phosphoric groups in OPs. The correlation between the most significant parameters such as contact time, OPs concentration, adsorbent dose, pH, as well as ionic strength with the adsorption capacities was optimized, and the effects of these parameters on the removal efficiency of GP and GF from the polluted aqueous solution were investigated. The adsorption of GP on UiO-67 was faster than that of GF, and a pseudo-second-order rate equation effectively described the uptake kinetics. The Langmuir model exhibited a better fit to adsorption isotherm than the Freundlich model. Thanks to the strong affinity and adequate pore size, the adsorption capacities in UiO-67 approached as high as 3.18 mmol (537 mg) g–1 for GP and 1.98 mmol (360 mg) g–1 for GF, which were much higher than those of many other reported adsorbents. The excellent adsorption characteristics of the current adsorbents toward OPs were preserved in a wide pH window and high concentration of the background electrolytes. These prefigured the promising potentials of UiO-67 as novel adsorbent for the efficient removal of OPs from aqueous solution.Keywords: decontamination; metal−organic frameworks; organophosphorus pesticides; porous adsorbents; UiO-67; water treatment

Zr-based MOF nanoparticles were applied as efficient carriers for alendronate delivery, and an unprecedented drug loading capacity was achieved thanks to the inherent drug anchorages of Zr–O clusters therein. The encapsulated drug featured with a pH-dependent release profile, and inhibited the growth of cancer cells more efficiently than the free drug.

Although the development of sensors for the detection of Cu2+ ions has significant importance, sensitive and selective recognition systems are still limited. Herein, the non-fluorescent small molecule of 2-bromomaleimide (BM) was firstly converted to 2-aminomaleimide (NM) by a simple nucleophilic addition–elimination reaction with pre-grafted amino groups in the meso-space of mesoporous silica nanoparticles (MSNs), and then was designed as fluorescent “on–off” probes for Cu2+ ion recognition. The strong green fluorescence emitted from the pendent NM was induced by the interaction between the lone electron pairs of the N atoms in amino groups and the conjugated maleimide rings. The fluorescence of MSNs labelled NM (MSNs-NM) could be selectively quenched by Cu2+ ions in aqueous solution and consequently exhibited sensitive fluorescence “on–off” switching effects for Cu2+ ions. The detection limit was as low as 0.28 μM Cu2+, which was far below the U.S. EPA limit of 20 μM. This prefigured the potential applications of the current chemosensor for the detection of Cu2+ ions in aqueous solution and in living cells. The small-angle XRD, TEM, BET, FT-IR, UV-vis absorption measurements all agreed on the fact that the sensitive probes of BM had been successfully labelled at the pore surface of MSNs.

•Mesoporous shell integrated with carboxylic groups were coated on magnetic Fe3O4.•The carriers show high magnetization and large cisplatin loading capacity.•The loaded cisplatin demonstrated a pH-dependent and sustained release feature.•Cisplatin was effectively delivered to cancer cells and induced their apoptosis.The synthesis of the core–shell magnetic mesoporous silica nanocomposites has recently attracted much attention, while it is highly desirable to modify the mesoporous shell with organic components for special interaction with guest molecules. Herein we propose a facile strategy to prepare novel magnetic mesoporous nanocomposites with superparamagnetic Fe3O4 core and mesoporous silica shell functionalized with pendant carboxylic groups in their mesopore interior. The successful deposition of organic–inorganic mesoporous layer on magnetic nanoparticles is verified by XRD, TEM and BET characterizations, and the integration of organic units is manifested by FT-IR and solid state NMR techniques. The inherent carboxylic units on the obtained nanocomposites serve as effective drug anchorages for coordinating with Pt atoms in the anti-cancer drug of cisplatin, resulting in increased drug loading amount and its sustained release. The obtained nanocomposites exhibit excellent water dispersity with well-defined size distribution (around 85 nm), ordered mesoporous characteristics, superparamagnetism and high magnetization (37.0 emu g−1). The nanocomposites could not only effectively transport the encapsulated cisplatin into cancer cells but also mediate its sustained release in endosomes or lysosomes, leading to enhanced antitumor efficiency against both A549 and MCF-7 cell lines.

•Monodispersed large-pore mesoporous silica nanoparticles (MSNs) were obtained.•The nanoparticles presented well-ordered mesostructure and small particle size below 150 nm.•The obtained MSNs demonstrated great capabilities for protein encapsulation.•In vitro experiment prefigured their potentials as protein delivery vehicles.Despite their great potentials as biomacromolecues delivery vehicles, there are few, if any, reports on mesoporous silica nanoparticles (MSNs) simultaneously integrated with the merits of large pore size, small particle diameters and well-ordered mesostructure. Here, we designed a facile strategy for the synthesis of monodispersed MSNs using cationic surfactants (CSs) as templating agents, neutral amine of N,N-dimethylhexadecylamine (DMHA) as a pore size mediator and tri-block copolymer of F127 (EO106PO70EO106) as a particle growth inhibitor/dispersant. The obtained colloidal nanoparticles exhibited a highly ordered mesostructure and tunable pore diameter up to 4.6 nm (BJH) and monodispersed particle sizes less than 150 nm. A model protein of cytochrome c (CytC) was exemplified to be accommodated in the resultant MSNs and its loading amount was correlated with their pore size. The efficient cancer cellular uptake of the large-pore MSNs prefigured their potentials as intracellular delivery vehicles for membrane-impermeable proteins.

Mesoporous silica nanocarriers with tunable particle sizes and different loadings of pendent carboxylic groups were successfully prepared by a straightforward and reproducible strategy, in which carboxyethylsilanetriol sodium salt was co-condensed with tetraethoxyorthosilicate to introduce the carboxylic groups. The key in this strategy was to separate the synthesis process into two steps of the nuclei formation and particle growth. The uniform particle size and ordered structure of the synthesized nanocarriers were manifested by several techniques such as XRD, TEM, SEM, and BET. DLS measurement illustrated that nanocarriers could be well suspended in aqueous solution. The integration and content tunability of the carboxylic groups within mesoporous silica nanoparticles (MSNs) were verified by FT-IR and 29Si NMR. The inherent carboxylic units on the obtained carboxylic group modified MSNs (MSNs-C) effectively enhanced the capture and tailored the release properties of the anticancer drug of cisplatin. The accumulation of drug in the HeLa cells was greatly enhanced due to the highly efficient platinum uptake efficiency transported by the synthesized nanocarriers. The drug encapsulated in the MSNs-C exhibited a higher antitumor activity than free cisplatin against both MCF-7 and HeLa cells.

A layer of PEG (poly(ethylene glycol))-galactose was successfully grafted onto the external surface of mesoporous silica nanoparticles (MSNs) via a new silane-free approach, while the internal surface of MSNs was preserved for the encapsulation of the widely used anti-cancer drug of doxorubicin (DOX). The nanosized morphology and ordered structure of the synthesized drug delivery vehicles were verified by XRD and TEM observations. The successful grafting of PEG layer and peripherally exposed galactose ligands on the external surface of MSNs (abbreviated as MSNs-P/G) was confirmed by FT-IR and solid 13C NMR. The high-density PEG layer effectively reduced the human serum protein (HSP) adsorbance to the surface of MSNs. The maximum DOX loading amount reached as high as 900 mg/g and the loaded drug released in a pH-dependent way. Both confocal laser scanning microscopy (CLSM) observation and flow cytometry measurements supported the facts that cellular uptake of MSNs-P/G was significantly higher than that of the pristine MSNs benefitting from the galactose-receptor-mediated endocytosis process. This was consistent with the higher cytotoxicity observed with the DOX@MSNs-P/G against the HepG2 cell line by MTT measurements.Graphical abstractHighlights► A silane-free route was developed to graft PEG onto the external surface of MSNs. ► The combined goals of drug delivery and liver cancer cell targeting were achieved. ► The loaded DOX demonstrated a pH-dependent release feature. ► DOX was more effectively delivered to targeted cells and induced their apoptosis.

Calcium doped mesoporous silica nanoparticles were successfully prepared and employed as efficient drug carriers for alendronate delivery. The incorporation of calcium ions dramatically enhanced the drug loading capacity and sustained release rate. The loaded alendronate more efficiently inhibited the growth of HeLa cancer cells than free drug.

An effective post-hydrothermal treatment strategy has been developed to dope highly dispersed iron catalytical centers into the framework of mesoporous silica, to keep the particle size in nanometric scale, and in the meanwhile, to expand the pore size of the synthesized mesoporous silica nanoparticles (MSNs). Characterization techniques such as XRD, BET, SEM and TEM support that the synthesized samples are long period ordered with particles size about 100 nm and a relatively large pore size of ca. 3.5 nm. UV–vis, XPS and EPR measurements demonstrate that the introduced iron active centers are highly dispersed in a coordinatively unsaturated status. NH3-TPD verifies that the acid amount of iron-doped MSNs is quite high. The synthesized nanocatalysts show an excellent catalytic performance for benzylation of benzene by benzyl chloride, and they present relatively higher yield and selectivity to diphenylmethane with a lower iron content and much shorter reaction time.Graphical abstractUniform MSNs with iron active centers and large pore size have been prepared by a newly developed strategy, which demonstrates enhanced catalytic performance for benzylation of benzene by benzyl chloride.Highlights► Iron species were introduced into the framework of mesoporous silica nanoparticles with uniform dispersion. ► The pore sizes of the synthesized nanocatalysts were expanded. ► The acidic site quantities were quite high and the acidic centers were accessible. ► The nanocatalysts presented higher yield and selectivity to diphenylmethane with significantly lower Fe content.

The uniform mesoporous carbon nanoparticles (MCNs) with size below 200 nm and good water dispersibility were successfully synthesized via a combined hydrothermal synthesis and hard templating. The prepared MCNs served as effective carriers for camptothecin which efficiently inhibited the growth of MCF-7 cancer cells after its sustained release therein.

Highly dispersed copper species were successfully coated onto the inner surface of the rodlike mesoporous SBA-15 silica by a newly developed strategy. The hydrophobic core of the surfactant micelle in the as-synthesized SBA-15 was effectively employed as a carrier for the hydrophobic precursors of copper acetyl acetonate (Cu(acac)2) during hydrothermal treatment (HT) before surfactant removal, and the copper-derivated catalysis centers within SBA-15 were strategically generated on pyrolysis. Characterizations of the synthesized samples by a series of techniques such as X-ray diffraction (XRD), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET), electron paramagnetic resonance (EPR), temperature-programmed reduction (TPR), UV–vis, X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma atomic emission spectroscopy (ICP–AES) manifested that about 0.19–0.85 wt % copper was directly introduced and dispersed into the inner surface of the SBA-15 pore network. While there were few studies, if any, to utilize synthetic copper catalysts for the selective oxidation of cyclohexane oxidation, it was found that currently synthesized Cu-SBA-15 demonstrated very interesting catalytic properties for this industrially important reaction. Under the optimized reaction condition at an oxygen pressure of 1 MPa and a temperature of 120 °C for 7 h, the conversion of cyclohexane to the target products was higher than 11%; meanwhile, the total selectivity to cyclohexanol and cyclohexanone satisfactorily reached ca. 80%.

High-density carboxyl groups have been successfully grafted onto the pore surface of mesoporous nanocarriers which served to complex with platinum atoms in cisplatin, leading to much increased drug loading efficiency, distinctly prolonged and pH-responsive cisplatin release, and greatly enhanced growth inhibition effect against MCF-7 and HeLa cancer cell lines.Keywords (keywords): mesoporous silica; anticancer drugs; cisplatin; drug delivery; nanoparticles; surface modification;

Highly dispersed silver nanoparticles embedded in mesoporous thin films (MTFs) have been synthesized by modification of the interior surface of mesoporous silica with ethylenediamine moieties, which provided the coordination sites for the Ag ions, and subsequent reduction under hydrogen atmosphere. TEM observations show the mesoporous parent films have effectively controlled the growth of the synthesized silver nanoparticles. The composite films had an ultrafast nonlinear response time, as fast as 200 fs, and a third-order nonlinear optical susceptibility of 0.94 × 10−10 esu, which was enhanced by the local field enhancement effect that was present when the silver nanoparticles were embedded in the surrounding dielectric matrix. The origin of the ultrafast nonlinear response and the enhanced nonlinearity of the composite films are attributed to the intraband transition of the free electrons near the Fermi surface of the incorporated silver nanoparticles.

The primary pollutant, radioactive iodine (I2), has become a worldwide concern due to its serious ill effects of radiotoxicity on human health. Therefore, it is of great significance to develop novel adsorbents for effectively eliminating I2 from nuclear waste. Herein, we reported a Zr-based MOF adsorbent constructed by utilizing pyridine-containing pyridine-dicarboxylic acid (PYDC) as organic ligands (UiO-66-PYDC) as well as active sites for the efficient removal of I2. UiO-66-PYDC MOFs were synthesized by a hydrothermal strategy and featured good chemical and thermal stabilities, endowing them with the ability to work in harsh environments. The abundant and inherent pyridine moieties in the developed adsorbent worked as active adsorption sites to capture I2. The correlation between the most significant parameters such as the contact time, adsorbate concentration, and reusability was optimized, and the interaction mechanism between I2 and UiO-66-PYDC was investigated in detail. As for the current adsorbent, a pseudo-second order rate equation was used to explain the removal kinetics, and the Langmuir model exhibited a better fit to the adsorption isotherm than the Freundlich model. Thanks to the strong affinity of PYDC ligands to I2 and high porosity, the adsorption capacities of UiO-66-PYDC for I2 could reach as high as 1250 mg g−1, which was much higher than those of many other reported MOFs. Additionally, the UiO-66-PYDC MOFs exhibited excellent renewable adsorption properties, prefiguring their great promise as green adsorbents for I2 removal in nuclear waste management.

The uniform mesoporous carbon nanoparticles (MCNs) with size below 200 nm and good water dispersibility were successfully synthesized via a combined hydrothermal synthesis and hard templating. The prepared MCNs served as effective carriers for camptothecin which efficiently inhibited the growth of MCF-7 cancer cells after its sustained release therein.

Zr-based MOF nanoparticles were applied as efficient carriers for alendronate delivery, and an unprecedented drug loading capacity was achieved thanks to the inherent drug anchorages of Zr–O clusters therein. The encapsulated drug featured with a pH-dependent release profile, and inhibited the growth of cancer cells more efficiently than the free drug.

The accurate characterization of low abundance phosphopeptides based on mass spectrometry (MS) techniques remains a challenge due to signal suppression by the large excess of interfering proteins and non-phosphopeptides. This demands better methods to effectively enrich phosphopeptides prior to MS analysis. In the current work, facilely synthesized Zr-based metal–organic frameworks (MOFs) of UiO-66 and UiO-67 have been successfully exploited as novel affinity materials for the enrichment and analysis of phosphopeptides. Thanks to their abundantly existent and naturally exposed Zr–O clusters, intrinsically large surface areas and highly ordered open cavities, UiO-66 and UiO-67 exhibited sensitive and specific enrichment of phosphopeptides with an interesting molecular sieving effect. An optimized protocol for loading, washing and elution was developed. Under these most optimized conditions, specific accumulation was demonstrated by the selective enrichment of phosphopeptides in the presence of abundant non-phosphorylated species. Meanwhile, high-abundance interfering proteins could be effectively excluded during the enrichment process. Additionally, the MOFs have also been successfully used to enrich phosphopeptides from human serum. These merits combined with their high chemical and thermal stabilities, make UiO-66 and UiO-67 highly promising for applications in phosphopeptidome research.

Luminescent metal–organic frameworks (LMOFs) have attracted significant attention as a unique class of sensing materials. In this work, the intrinsically fluorescent amino derivative of UiO-66 (UiO-66-NH2) was successfully exploited as a fluorescent probe for the sensitive and selective detection of phosphate anions in an aqueous medium. The inorganic Zr–O clusters and organic BDC-NH2 linkers in the elaborated UiO-66-NH2 MOFs were individually designed as phosphate recognition sites and signal reporters. The intrinsic fluorescence of BDC-NH2 was tuned from high to weak emission by ligand-to-metal charge transfer (LMCT) upon its integration into the framework of UiO-66-NH2 MOFs and this weakened fluorescence could be proportionally recovered in correlation with the applied phosphate level through a newly developed competitive coordination effect. The specificity for phosphate recognition of the employed sensory platform was scarcely affected by other possible interfering species. The efficacy of this strategy was demonstrated by a linear phosphate detection range of 5–150 μM and a limit of detection of 1.25 μM, which was far below the detection requirement of phosphate discharge criteria in the water environment. The possible sensing mechanisms for anionic phosphate detection using the currently established fluorescent probe, including host–guest interaction and structure–property correlation, were systematically investigated using XPS, FT-IR, XRD, TEM and N2 sorption techniques.