β-Cyclodextrin functionalization of metal-organic framework MOF-235 with excellent chemiluminescence activity for sensitive glucose biosensing

Colorimetric and Ratiometric Fluorescence Dual-Mode Sensing of Glucose Based on Carbon Quantum Dots and Potential UV/Fluorescence of o-Diaminobenzene

A novel colorimetric and ratiometric fluorescence sensor was constructed by using carbon quantum dots (CQDs) and o-diaminobenzene (ODB). Unlike ODB by itself, ODB oxide (oxODB) not only emits fluorescence, but also produces ultraviolet (UV) absorption. Therefore, on the basis of the potential optical properties of ODB, glucose oxidase (Gox) and horseradish peroxidase (HRP) were introduced into a CQDs⁻ODB system for the quantitative oxidation of ODB. When glucose is present, it is oxidized by oxygen under the catalytic action of its oxidase to form hydrogen peroxide. Hydrogen peroxide is a strong oxidant that can rapidly oxidize ODB through the catalysis of horseradish peroxidase. oxODB can cause changes in the fluorescence ratio (I550/I446) and absorbance ratio (A/A₀). At the same time, the color of the detection solution can also change under sunlight and ultraviolet lamps. Therefore, glucose can be quantitatively detected by ratiometric fluorescence and colorimetry simultaneously, and semi-quantitatively detected by observing the colors with sunlight and ultraviolet lamps of 365 nm. This increases not only the convenience but also the accuracy of detection. In addition, this sensor has good selectivity and can be used for the determination of glucose in serum, providing a new idea for the development of blood glucose sensors.

One-pot doping platinum porphyrin recognition centers in Zr-based MOFs for ratiometric luminescent monitoring of nitric oxide in living cells

A new kind of nanoscale MOFs probe for nitric oxide (NO) sensing has been successfully constructed by a one-pot strategy, in which the chemically stable UiO-66 crystal structure was achieved using platinum meso-tetra(4-carboxyphenyl)porphyrin (Pt-TCPP), 1,1,2,2-Tetra(4-carboxylphenyl)ethylene (H₄TCPE) and 1,4-dicarboxybenzene (BDC) as co-linkers (Pt-TCPP/H₄TCPE@UiO-66). Pt-TCPP was verified to serve as a signal reporter in NO sensing fields for the first time while H₄TCPE worked as a luminescence reference to build a ratiometric sensor. The integration of luminescent dyes in nanoscale MOFs effectively avoided their aggregation-caused quenching effect and poor aqueous dispersibility to rationalize NO detection in the aqueous phase. The obtained Pt-TCPP/H₄TCPE@UiO-66 nanoparticles (NPs) exhibited an excellent sensing property toward NO with an ultrahigh linear correlation of the Stern-Volmer equation and a rapid response time as short as 2 min. Moreover, the elaborated sensor could work under a wide pH window (7.4, 5.6 and 0) and the limit of detection (LOD) reached as low as 0.1420 µg mL^-1. The specificity of the obtained Pt-TCPP/H4TCPE@UiO-66 NPs toward NO sensing was scarcely affected by other possibly coexistent species in biological system. The in vitro monitoring for NO in living cells was also testified with these Pt-TCPP/H₄TCPE@UiO-66 NPs.

Engineering FeCo alloy@N-doped carbon layers by directly pyrolyzing Prussian blue analogue: new peroxidase mimetic for chemiluminescence glucose biosensing

Direct pyrolysis of a Prussian blue analogue produced FeCo@NC with high and stable peroxidase-like activity, which catalyzes luminol oxidation by H₂O₂ to generate strong CL emission, and this finding results in a new CL biosensor for glucose.

Bio-related applications of porous organic frameworks (POFs)

Porous organic frameworks (POFs) are promising candidates for bio-related applications. This review highlights the recent progress in POF-based bioapplications, including drug delivery, bioimaging, biosensing, therapeutics, and artificial shells. These encouraging performances suggest that POFs used for bioapplications deserve more attention in the future.

Iron-based metal–organic framework as an effective sorbent for the rapid and efficient removal of illegal dyes

A metal organic framework (MOF-235) was fabricated by a simple solvothermal method and utilized as an adsorbent for the selective removal of electron-rich conjugated dyes.