Ultrasensitive Photoelectrochemical Assay for DNA Detection Based on a Novel SnS₂/Co₃O₄ Sensitized Structure

Abstract

In this work, an ultrasensitive photoelectrochemical (PEC) assay was established for sensitive DNA detection based on a novel SnS2/Co3O4 sensitized structure as a photoactive matrix and benzo-4-chlorohexadienone (4-CD) precipitate as a signal quencher. Noticeably, the photoelectric conversion efficiency of the SnS2/Co3O4 sensitized structure was dramatically enhanced due to the effective sensitization of Co3O4 toward SnS2, thus attaining an intense photocurrent response, which was sixfold higher than that of pristine SnS2. Additionally, with the assistance of Nt.BstNBI enzyme-assisted target cycling process, a limited amount of target DNA (a fragment of p53 gene) could be converted into extensive output DNA, which could hybridize with capture DNA to yield abundant DNA duplex for loading mimetic enzyme manganese porphyrin (MnPP). Subsequently, 4-chloro-1-naphthol (4-CN) could be catalyzed to form 4-CD precipitate by MnPP on the modified electrode surface with the existence of H2O2. Then, the 4-CD precipitate severely hampered electron transfer, causing a prominently diminished photocurrent response for DNA determination. The elaborated PEC assay not only extended the application of SnS2 in the PEC biosensing field but also manifested a wide linear range of 100 aM to 1 nM with a low detection limit of 30 aM, exhibiting enormous potential for the detection of various biomarkers or other targets in bioanalysis and disease diagnosis fields.

Enzymatic Behavior Regulation-Based Colorimetric and Electrochemiluminescence Sensing of Phosphate Using the Cobalt Oxyhydroxide Nanosheet

“…The TEM images revealed the hexagonal ultrathin sheet structure of the obtained CoOOH nanosheet (Figure B), which was then confirmed by diamond crystal structure analysis (Figure S1A). The results of the crystal structure suggested a 2D nanosheet structure of as-synthesized CoOOH with the CoO 6 layer crystal (Figure S1B,C), which matched with other reports. , As displayed in Figure C,D, an average size of 91.5 nm and an average thickness of 11.6 nm of the CoOOH nanosheet were presented.…”

“…The results of the crystal structure suggested a 2D nanosheet structure of as-synthesized CoOOH with the CoO 6 layer crystal (Figure S1B,C), which matched with other reports. 42,43 As displayed in Figure 1C,D, an average size of 91.5 nm and an average thickness of 11.6 nm of the CoOOH nanosheet were presented.…”

“…Moreover, it could produce strong photoluminescence once put into water (Figure S7). The CoOOH nanosheet with a peroxidase-like activity could efficiently catalyze 4-CN to generate a precipitate (oxidation state, 4-CD) via the following equation …”

Proton-Regulated Catalytic Activity of Nanozymes for Dual-Modal Bioassay of Urease Activity

“…Nevertheless, the development of an advanced functional dual-modal photoelectrochemical (PEC) and electrochemical (EC) sensing platform remains meaningful for urease detection. Recently, PEC analysis, as a novel and promising analysis technique, exhibits the merits of low cost, simple operation, antibackground interference, high sensitivity, and miniaturization, and provides great opportunities for fast and real-time detection. − To realize a highly sensitive PEC biosensing, some effective signal amplification strategies have been developed, such as enzymatic reactions, the steric effect, energy transfer, and the quenching effect . Among them, PEC enzymatic biosensors, which combine the selectivity of enzymes and the sensitivity of PEC bioanalysis, are deemed to promote their further advancements. , However, natural enzymes usually suffer from the disadvantages of high cost, poor stability, and storage difficulties, which limit their widespread applications. − Moreover, enzyme immobilization on the surface of a photoelectrode will inevitably hinder the electron transfer and mass exchange during the PEC process due to the insulating characteristics of natural enzymes.…”

Target-Dependent Gating of Nanopores Integrated with H-Cell: Toward A General Platform for Photoelectrochemical Bioanalysis

“…As an important component for the H-cell, the separator, with specific pores and regulatory capacity, is the essential place where two solutions meet and specific entities could cross via a selective directional manner. The accessibility and versatility of customized H-cells have thus ignited our strong interest to exploit their potential application in the field of PEC bioanalysis, a rapidly developing sensing technology on the basis of various photoelectrodes. − …”