Recent Progress of Covalent Organic Frameworks Applied in Electrochemical Sensors

Abstract

As an emerging porous crystalline organic material, the covalent organic frameworks (COFs) are given more and more attention in many fields, such as gas storage and separation, catalysis, energy storage and conversion, luminescent devices, drug delivery, pollutant adsorption and removal, analysis and detection due to their special advantages of high crystallinity, flexible designability, controllable porosities and topologies, intrinsic chemical and thermal stability. In recent years, the COFs are applied in analytical chemistry, for instance, chromatography, solid-phase microextraction, luminescent and colorimetric sensing, surface-enhanced Raman scattering and electroanalytical chemistry. The COFs decorated electrodes show high performance for detecting trace substances with remarkable selectivity and sensitivity, such as heavy metal ions, glucose, hydrogen peroxide, drugs, antibiotics, explosives, phenolic compounds, pesticides, disease metabolites and so on. This review mainly summarized the application of COF based electrochemical sensor according to different target analytes.

Expanding the horizons of covalent organic frameworks: sub-stoichiometric synthesis as an emerging toolkit for functional COFs

“…49–52 The field has also witnessed the utilization of unreacted sites, the introduction of non-interfering functional groups, and post-synthetic modifications that functionalize the pores or transform the linkages. 30,33,53 The functional versatility of such framework materials has led to various applications, including gas adsorption/separation, 54–57 host–guest chemistry, 58–61 sensing, 62–68 ion capture/transport, 69 catalysis, 70–76 and electrochemical applications. 77…”

Combination of covalent organic frameworks (COFs) and polyoxometalates (POMs): the preparation strategy and potential application of COF–POM hybrids

“…5–10 With the development of COFs, metal-based building blocks have also been employed to construct the metal based COFs, which not only enriches the types of COFs, but also offers more properties. 11–13 As reported, COFs possess a wide range of potential applications, including gas storage and separation, 14,15 catalysis, 16,17 sensing, 18,19 advanced electronics, 20,21 and drug delivery. 22,23 They are also extremely lightweight and have a high surface area, making them attractive for use in energy storage systems such as batteries 24,25 and supercapacitors.…”

“…52 At present, there are various type of bonds for connecting the building blocks, and a large number of COFs with different structures have been continuously reported. 18…”

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

“…COF is a kind of crystalline porous organic material possessing a high surface area, a controllable structure, and adjustable pore size, which has been employed to fabricate various electrochemical sensors in recent years. , To ingeniously modulate the structures and properties of COF by using different monomers, the stability, selectivity, and sensitivity of functionalized electrochemical sensors can be precisely controlled and enhanced. 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 .…”