A novel luminescent cadmium(II) MOFs exhibiting a sensitive and selective detection of trace amounts of nitroaromatics with excellent recyclability

Facile preparation of mesoporous silica coated nitrogen doped carbon dots for sensitive detection of picric acid

In this work, a nanocomposite suitable for long-term storage was constructed for efficient and highly selective detection of picric acid (PA). For this purpose, nitrogen-doped carbon dots (N-CDs) were synthesized by a simple hydrothermal reaction one-step method, and the synthesized nitrogen-doped carbon dots were loaded into amine-modified mesoporous silica nanoparticles (MSN-NH₂) to form N-CDs@MSN-NH₂ nanocomposites. The as-synthesized N-CDs@MSN-NH₂ was detected by X-ray photoelectron spectroscopy (XPS) and the Fourier transform infrared (FT-IR) analysis methods. After being coated with MSNs, the as-synthesized N-CDs@MSN-NH₂ exhibits excellent photo-stability in storage for 60 days at room temperature. Furthermore, PA can significantly quench the fluorescence signal of N-CDs@MSN-NH₂ through the fluorescence resonance energy transfer (FRET) effect, while other metal ions and nitro compounds only cause little change. The a-synthesized composites were used to detect PA with a detection limit of 50 nM in an aqueous solution. These results indicate that the synthesized composites have promise for application in PA detection in aqueous solution.

In-vitro evaluation of the 5-fluorouracil loaded GQDs@Bio-MOF capped with starch biopolymer for improved colon-specific delivery

Herein, for the first time, the photoluminescent graphene quantum dots@Bio-metal organic framework (GQDs@Bio-MOF) nanohybrid was prepared. BET analysis obtained the average pore diameter of GQDs@Bio-MOF about 11.97 nm. The existence of nanoscale porosity in GQDs@Bio-MOF displays its suitability for 5-Fu loading owing to the smaller size of 5-Fu. 5-Fu entrapment efficiency and loading capacity were found to be ~42.04 % and ~4.20 %, respectively (5-Fu@GQDs@Bio-MOF). The 5-Fu@GQDs@Bio-MOF was capped with starch biopolymer (St@5-Fu@GQDs@Bio-MOF), fabricated sample displayed 4.67 for pH_PZC. SEM analysis displayed that the St@5-Fu@GQDs@Bio-MOF microspheres have a spherical shape with a diameter of ~2 μm. The in vitro drug release assay displayed better release behavior for St@5-Fu@GQDs@Bio-MOF than 5-Fu@GQDs@Bio-MOF, releasing about 62.3 % of the entrapped 5-Fu within 96 h of incubation. The 5-Fu release showed the best fitting with the Higuchi model with R² 0.9884. The in vitro cytotoxicity screening outcomes displayed that the St@GQDs@Bio-MOF is a promising biocompatible carrier, with cell viability of higher than 84 %. Accumulation of the results revealed that the St@5-Fu@GQDs@Bio-MOF is a new system with advantages of sustained drug release and biocompatibility that are the main criteria for each newly designed anticancer drug carrier.

Solvo-thermal synthesis of a unique cluster-based nano-porous zinc(II) luminescent metal-organic framework for highly sensitive detection of anthrax biomarker and dichromate

In this work a flexible multi-dentate 4,4'-(1H-1,2,4-triazole-1-yl) methylene-bis(benzonic acid) (H₂L) ligand has been employed, a unique cluster-based nano-porous luminescent zinc(II) metal-organic framework {[Zn(μ₆-L)]·(DMAC)₂}_n (1) (DMAC = Dimethylacetamide) has been isolated under solvo-thermal conditions. The H₂L ligand adopts hexa-dentate coordination modes via one triazole nitrogen atom and four aromatic carboxylate oxygen atoms, which bridge the neighboring six-coordinated Zn^II centers, leading to a three-dimensional (3D) nano-porous metal organic framework. A PLATON program analysis suggests the total potential solvent area volume is 2028.9 Å³, which occupy 62.5% percent of the unit cell volume (3248.4 Å³). PXRD Patterns of the as-synthesized samples 1 have been determined confirming the purity of the bulky samples. Photo-luminescent properties indicate strong fluorescent emissions of 1 at the room temperature. Further photo-luminescent measurements show that 1 can exhibit highly sensitive real-time luminescence sensing of anthrax biomarker dipicolinic acid (DPA) with high quenching efficiency (K_SV = 1.48 × 10⁵ M^-1) and low detection limit (0.298 μM (S/N = 3)). Meanwhile 1 also exhibits highly selective and sensitive luminescence sensing for Cr₂O₇^2- ions in aqueous solutions with high quenching efficiency K_SV = 1.22 × 10⁴ L·mol^-1 and low detection limit (0.023 μM (S/N = 3)). Therefore 1 can be used a unique multi-functional 3D cluster-based metal organic material in sensitive detection and effective detection of environment pollutants and biomarker molecules.

Sensing organic analytes by metal–organic frameworks: a new way of considering the topic

In this review, our goal is comparison of advantageous and disadvantageous of MOFs about signal-transduction in different instrumental methods for detection of different categories of organic analytes.

Three new coordination polymers based on bis(4-(4H-1,2,4-triazol-4-yl)phenyl)methane: syntheses, structures, multiresponsive luminescent sensitive detection for antibiotics and pesticides, and antitumor activities

Three novel coordination polymers (CPs), namely, {[Ag2(L)2(Mo4O13)·(CH3CN)]} n (1), {[Zn(L)(1,4-bdc)2·2(1,4-H2bdc)]} n (2), {[Cd(L)(1,4-bdc)0.5]} n (3) have been synthesized under solvothermal conditions by the reaction of bis(4-(4H-1,2,4-triazol-4-yl)phenyl)methane (L) and varied metal salts. Their structures are determined by single X-ray crystal diffraction, and further characterized by elemental analysis, IR, TGA and PXRD. CP 1 with ammonium molybdate as a secondary ligand displays a 2D network with (2,3,3,3,4)-connected net topology and the point symbol of {4·82}6{4·84·10}2{8}, CP 2 and CP 3 with 1,4-H2bdc as a secondary ligand demonstrate 3D structures with different topologies. CP 2 exhibits high sensibility and low detection limit in the recognition of antibiotics (NZF, NFT and FZD) and pesticide (DCN) identification. CP 1 demonstrates good anti-tumor activity toward the tested glioma cells. The possible luminescent sensitivity and anti-tumor mechanisms are also discussed.