Double Photosystems-Based ‘Z-Scheme’ Photoelectrochemical Sensing Mode for Ultrasensitive Detection of Disease Biomarker Accompanying Three-Dimensional DNA Walker

Abstract

A new double photosystems-based 'Z-scheme' photoelectrochemical (PEC) sensing platform is designed for ultrasensitive detection of prostate-specific antigen (PSA) by coupling with a three-dimensional (3D) DNA walker. Two photosystems consist of CdS quantum dots (photosystem I; PS I) and BiVO photoactive materials (photosystem II; PS II), whereas gold nanoparticles (AuNPs) photodeposited on high-active {010} facets of BiVO are used as the electron mediators to promote electron transfer from conduction band of PS II to valence band of PS I. 3D DNA walker-based amplification strategy is carried out between hairpin DNA1 conjugated onto the AuNP, hairpin DNA2 labeled with CdS quantum dot (QD-H2), and DNA walker complementary with the PSA aptamer modified to a magnetic bead (Apt-MB). Upon addition of target, DNA walker strand is displaced from DNA walker/Apt-MB to open hairpin DNA1 on AuNP@BiVO. In the presence of QD-H2, DNA walker induces the hybridization of DNA1 with DNA2 on the gold nanoparticles step by step, thereby resulting in the assembly of CdS QDs on the AuNP@BiVO to form Z-scheme double photosystems with strong photocurrent. Under optimum conditions, the Z-scheme PEC sensing system exhibits good photocurrent responses toward target PSA within the working range of 0.01-50 ng mL at a low detection limit of 1.5 pg mL. Good reproducibility and accuracy are acquired for analysis of target PSA and human serum specimens relative to the commercial PSA ELISA kit. Importantly, our strategy provides a new horizon for photoelectrochemical in vitro diagnostics.

In Situ Immobilized Sesamol-Quinone/Carbon Nanoblack-Based Electrochemical Redox Platform for Efficient Bioelectrocatalytic and Immunosensor Applications

“… 1 − 5 In this context, nonhazardous and ecofriendly redox-active molecules are pressingly needed for pollution-free electrochemical applications. Most often, redox systems such as quinone, 2 , 4 organic dyes, 6 − 9 metals, 10 − 12 metal oxides, 13 − 15 complexes like Fe(CN) 6 3– , 16 − 19 and organometallic systems like ferrocene and its derivatives 19 − 21 have been used as homogeneous/heterogeneous mediators for various electrochemical, electro-organic, and electroanalytical applications. Indeed, these redox chemicals have been considered as hazardous, toxic, and environment polluting substances.…”

An electrochemical aptasensor for lead ion detection based on catalytic hairpin assembly and porous carbon supported platinum as signal amplification

“…14, 15 Based on these unique properties, many electrochemical sensors based on aptamers have been fabricated for ultrasensitive detection of Pb 2+ . 16,17 In order to further amplify response signal and enhance the sensitivity, different signal amplication techniques including palindromic molecular beacon (PMB), 18 rolling circle amplication (RCA), 19 DNA walker, 20 hybridization chain reaction (HCR) 21 and catalytic hairpin assembly (CHA) 22 have attracted increasing attention. Among them, as isothermal nucleic acid amplication strategy, with the simple reaction conditions, high sensitivity and the low costs, CHA is powerful for amplifying and transducing signals at the terminus of nucleic acid amplication reactions, 23,24 and has been broadly applied in electrochemical sensing platforms.…”

Semimetal Bismuth‐Enhanced Light Adsorption and Interface Charge Transfer in Bi@BiVO4

“…However, the photoactivity still remains unsatisfactory for the practical applications due to a low electric conductivity and a low charge separate efficiency . To date, many strategies are developed to enhance its photoactivity . Among them, that noble‐metal‐based Schottky junctions are demonstrated to be one of the most efficient methods.…”

“…Among them, that noble‐metal‐based Schottky junctions are demonstrated to be one of the most efficient methods. Typically, Au decoration has greatly improved photoelectric propensities of BiVO 4 photoanode . However, its high cost and rare resource severely limit the wide application.…”