Reversed Regulation Effects of ssDNA on the Mimetic Oxidase and Peroxidase Activities of Covalent Organic Frameworks

Abstract

Nanomaterials with enzyme mimetic activity have attracted extensive attention, especially in the regulation of their catalytic activities by biomolecules or other polymers. Here, a covalent organic framework (Tph‐BT COF) with excellent photocatalytic activity is constructed by Schiff base reaction, and its mimetic oxidase activity and peroxidase activity is inversely regulated via single‐stranded DNA (ssDNA). Under light‐emitting diode (LED) light irradiation, Tph‐BT exhibited outstanding oxidase activity, which efficiently catalyzed oxidation of 3,3′,5,5′‐tetramethylbenzidine (TMB) to produce blue oxTMB, and ssDNA, especially those with poly‐thymidine (T) sequences, can significantly inhibit its oxidase activity. On the contrary, Tph‐BT showed weak peroxidase activity, and the presence of ssDNA, particularly poly‐cytosine (C) sequences, can remarkably enhance the peroxidase activity. The influence of base type, base length, and other factors on the activities of two enzymes is also studied, and the results reveal that the adsorption of ssDNA on the surface of Tph‐BT prevented intersystem crossing (ISC) and energy transfer processes to reduce 1O2 generation, while the electrostatic interaction between ssDNA and TMB enhanced Tph‐BT's affinity for TMB to facilitate the electron transfer from TMB to •OH. This study investigates multitype mimetic enzyme activities of nonmetallic D‐A conjugated COFs and demonstrates their feasibility of regulation by ssDNA.

Bioinspired FeN5 Sites with Enhanced Peroxidase-like Activity Enable Colorimetric Sensing of Uranyl Ions in Seawater

“…As the main form of uranium, UO 2 2+ is distributed in the Earth’s crust and oceans. , Due to the continuous escalation of human activities, such as nuclear testing, nuclear accidents, and the discharge of wastewater from nuclear power plants, uranium’s profound chemical and radiological toxicity poses an increased risk to human health. , Therefore, it is necessary to develop a sensing platform with high sensitivity and accuracy to realize UO 2 2+ detection (Figure a). Accordingly, based on the unique structure and electronic properties of actinide U, the hybridization of 5d-6f orbital results in the linear structure of UO 2 2+ (OUO) 2+ . ,, The presence of the single electron on the N of the imine (–NH) in the oxTMB can form the complex with UO 2 2+ ions. , In detail, the binding energy peak of U 4f of the complex is observed in the XPS spectrum (Figure b). Moreover, the N 1s spectra of oxTMB with and without UO 2 2+ were compared, respectively.…”

“…23,40,41 The presence of the single electron on the N of the imine (−N�H) in the oxTMB can form the complex with UO 2 2+ ions. 42,43 In detail, the binding energy peak of U 4f of the complex is observed in the XPS spectrum (Figure 4b). Moreover, the N 1s spectra of oxTMB with and without UO 2 2+ were compared, respectively.…”

Programming of a Portable Digital Monitoring System-Integrated DNA Aptamer Reversely Regulated Oxidase-Like Nanozyme for Real-Time Dynamic Analysis of Atmospheric Perfluorooctanoic Acid

“…37 These results indicated that the presence of PFOA could selectively bind to its Apt for forming DNA secondary structure-based conformation change, weakening of the π−π interactions to trigger the dissociation of Apt away from the surface of PtCoNPs@g-C 3 N 4 . 44 As a result, the oxidase-like activity of Apt-PtCoNPs@ g-C 3 N 4 was activated and restored to produce O 2…”

Research Progress on the Application of Covalent Organic Framework Nanozymes in Analytical Chemistry

“…The surface of COFs has abundant functional groups and active sites, which are po tential targets for constructing nanozymes. Zhang et al [26] used a solvothermal synthesis method to prepare an imine-linked tetragonal COF nanozyme (Tph-BDP) through the combination of [C2 + C4] (Figure 3A). Under the illumination condition of LED light, Tph BT has high simulated oxidase activity.…”