Cathode–Anode Spatial Division Photoelectrochemical Platform Based on a One-Step DNA Walker for Monitoring of miRNA-21

Abstract

Photoelectrochemical (PEC) biosensors carried out the whole reaction process in the same solution, which would limit the sensitivity and selectivity of detection in the sensing system. Herein, we reported a promising new cathode–anode spatial division PEC platform based on the two-electrode synergistic enhancement strategy. With the photoanode and photocathode integrated in the same current circuit, the platform exhibited an increased photocurrent response, as well as an improved anti-interference ability led by separating the two electrodes spatially. In this proposal, red light-driven AgInS2 nanoparticles (NPs) served as the photoanode to build biometric steps and amplify the signal, whereas p-type PbS quantum dots were selected as the photocathode to increase the signal. With the participation of alkaline phosphatase (ALP) labeled on Au NPs–DNA, ascorbic acid 2-phosphate was catalyzed to produce ascorbic acid as an electron donor, resulting in the enhancement of the PEC signal. Interestingly, in the presence of miRNA-21 and T7 Exo, the one-step DNA walker amplification can be triggered to reduce the PEC signal by releasing ALP-Au NP–DNA. The constructed PEC biosensor exhibited a detection limit of as low as 3.4 fM for miRNA-21, which was expected to be applied to early clinical diagnosis. Also, we believe that the proposed cathode–anode spatial division PEC platform can open up a new view for the establishment of other types of PEC biosensors.

Dual-Engine Powered Paper Photoelectrochemical Platform Based on 3D DNA Nanomachine-Mediated CRISPR/Cas12a for Detection of Multiple miRNAs

“…The traditional photoanode/photocathode biosensors based on the three-electrode mode have problems related to spatial interference, such as contact cross talk between electrodes and interference of electrolytes on electron transfer both caused by co-region detection. , On the one hand, the photoanode and photocathode are employed simultaneously to replace the original single photoelectrode, so that the dual power of mutual excitation is obtained to amplify the photocurrent signal . On the other hand, owing to the flexibility and biocompatibility of a paper-based microfluidic chip, , spatial segmentation is realized between electrodes to increase physical spacing and reduce interference.…”

Highly Selective Photoelectrochemical Assay of Arsenate Based on Magnetic Co3O4–Fe3O4 Cubes and the Negative-Background Signal Strategy

“…Herein, we reported an iron phthalocyanine (FePc)-induced switchable photocurrent-polarity platform for highly selective detection of As­(V) based on the good dispersibility of magnetic Co 3 O 4 –Fe 3 O 4 cubes and low toxicity and high photoelectric activity of silver indium sulfide (AgInS 2 ) (Scheme ). First, the magnetic Co 3 O 4 –Fe 3 O 4 cubes were obtained by the calcination of CoFe Prussian blue analogue (PBA), and then, the Co 3 O 4 –Fe 3 O 4 cubes were functionalized with oligonucleotide (S1) based on the formation of surface complexes between metal ions and phosphate backbones of single-stranded DNA. − In the presence of As­(V), S1 could be released based on the stronger affinity between As­(V) and Co 3 O 4 –Fe 3 O 4 cubes.…”

Photoelectrochemical Detection of Exosomal miRNAs by Combining Target-Programmed Controllable Signal Quenching Engineering

“…33 Traditional methods usually rely on biorecognition molecules immobilized on photoelectrodes for special identification. 34 Nevertheless, the fixation of biorecognition probes generally requires particular experiment conditions and complicated processes and might result in a higher background signal or a lower signal response. 35 Nevertheless, the homogeneous and immobilization-free bioassay would avoid above disadvantages.…”

“…Generally, biomolecule recognition is one of the primary elements for biosensing . Traditional methods usually rely on biorecognition molecules immobilized on photoelectrodes for special identification . Nevertheless, the fixation of biorecognition probes generally requires particular experiment conditions and complicated processes and might result in a higher background signal or a lower signal response .…”