2D Conductive Covalent Organic Frameworks with Abundant Carbonyl Groups for Electrochemical Sensing

Abstract

Due to their permanent porosity, robust chemical stability, and tunable structure, covalent organic frameworks (COFs) are very attractive in the application of energy storage, catalysis, sorption, and sensing. However, the very low conductivity of COFs severely restricts their application in electrochemical sensing. Here, an aza-fused π-conjugated COFs with abundant carbonyl groups (COF1) was synthesized and deployed as electrode materials in electrochemical sensing for the first time. The current response of the acetylcholinesterase biosensor based on COF1 increases three times when compared to the electrode without COF1. The effects of carbonyl groups on signal enhancement were proved in depth by a series of characterization and comparison experiments with the prepared COF2 without carbonyl groups. The results demonstrated that exposed carbonyl active sites of COF1 can promote the effective immobilization and bioactivity preserving of enzyme molecules and contribute to the enrichment of analytes. Together with the good conductivity of COF1 derived from a fully extended 2D aromatized π-conjugated system, all of which improve the biosensor performance. The COF1-based biosensor exhibited fast response speed, high sensitivity, good selectivity and practicability, and robust stability for organophosphorus pesticide detection and proved to be a promising tool for the rapid and onsite detection of organophosphorus pesticides in the environment.

Postsynthetic Modification Strategy for Constructing Electrochemiluminescence-Active Chiral Covalent Organic Frameworks Performing Efficient Enantioselective Sensing

“…After optimization of different simulated stacking models, an inclined stacking model is most likely with a distance of 5.4 Å between layers (Figure S7). − Besides that, the PXRD pattern of Ph-triPy + -( R )-Ru­(II) basically remains unchanged compared with Ph-triPy + -biPy. Meanwhile, Ph-triPy + -biPy and Ph-triPy + -( R )-Ru­(II) show the almost same SEM images (Figure S8), indicating that their surface and phase topography are unaffected by the introduction of the chiral Ru-ligand.…”

“…The films belong to the typical type III isotherm curve with a sharp uptake at P / P 0 = 0.9–1.0. The BET surface area of Ph-triPy + -biPy is only 63.7 m 2 g –1 due to the unique stacking model. − As a result of the inclined stacking with a large lamellar spacing, the porosity cannot be fully accessed. Meanwhile, the chloride counterion of COFs also occupies a part of the space .…”

Highly Sensitive Gas Sensor for Detection of Air Decomposition Pollutant (CO, NOx): Popular Metal Oxide (ZnO, TiO2)-Doped MoS2 Surface

“…In recent years, the gas component analysis method represented by SF 6 decomposition component detection has become a research hotspot at home and abroad. − Inspired by the above research, the detection of air decomposition components under PD is proposed to realize the detection and diagnosis of insulation faults of air switchgear. There are many cases where scholars in the field of theoretical chemistry have explored gas-sensitive materials for CO, NO, and NO 2 gases. − However, most of the cases have studied only one or two of these gases. There are fewer cases in which gas-sensitive materials for these three gases have been explored simultaneously in the context of PD faults in air switchgear.…”

COF-Coated Microelectrode for Space-Confined Electrochemical Sensing of Dopamine in Parkinson’s Disease Model Mouse Brain

“…A variety of substances including metal ions, neurotransmitters, drugs, disease metabolites and explosives in water, biofluids, or tissues can be detected by COF-based electrochemical sensors. , For example, Zhu et al modified the screen-printed electrode with an ultrathin bithiazole-based COF for the detection of organophosphorus pesticides, attaining a high sensitivity and low limit of detection . Lu et al fabricated a kind of biocompatible two-dimensional (2D) conductive COF with abundant carbonyl groups to modify the glassy carbon electrode for detecting paraoxon . We have recently synthesized COFs with tunable lipophilicity to modify the electrode, realizing the selective detection of vitamin A and vitamin C in the multivitamin tablets …”

“…44 Lu et al fabricated a kind of biocompatible two-dimensional (2D) conductive COF with abundant carbonyl groups to modify the glassy carbon electrode for detecting paraoxon. 45 We have recently synthesized COFs with tunable lipophilicity to modify the electrode, realizing the selective detection of vitamin A and vitamin C in the multivitamin tablets. 46 Herein, we demonstrate that the fascinating structural and physiochemical properties of COF can provide the cCFE an excellent in vivo performance with enhanced antibiofouling and antichemical fouling ability, selectivity, and stability.…”