Target-engineered photo-responsive of the DNA strands: a novel signal-on photoelectrochemical biosensing platform for Ochratoxin A
The work reports a novel and efficient method for converting the photo-responsive of the DNA strand and the validation of its feasibility for using as a versatile signal amplified system for constructing photoelectrochemical (PEC) DNA sensor. Emeraldine polyaniline molecule could grow and enwrap the long linear DNA polymeric skeleton with the catalytic ability of embedded fenton reagent and DNAzyme. Indeed, the DNA backbone converted to the photoactive matrix that can efficiently enhance the utilization of visible light, thus improving the photocurrent response in essence. Inspired by this phenomenon, employing the long linear DNA polymeric skeleton which generated by target-triggered hybrid chain reaction as the template for loading ferrous ions and DNAzyme, an distinctive PEC platform was proposed based on decahedral Au-BiVO4@MoS2 as the photoactive substance. The generated PANI wire can efficient adsorption of light in the visible region and produced more electrons, thus further restrain the electron-hole recombination of Au-BiVO4@MoS2, endowing the DNA sensor with excellent analytical performance. Under optimal conditions, the proposed PEC assay shows excellent sensitivity for detection of ochratoxin A with a low detection limit of 0.14 pg mL-1 and wide linear range from 0.25 pg mL-1 to 25 ng mL-1. Moreover, it presents good stability, satisfactory accuracy, and is a promising methodology for determination of multiple other targets by replacing the recognition elements.