HCR/DNAzyme-triggered cascaded feedback cycle amplification for self-powered dual-photoelectrode detection of femtomolar HPV16

Abstract

For high-performance dual-photoelectrode assay, developing a pair of photoactive materials with well-matched band structure and the design of a powerful sensing strategy are highly desirable. Herein, the Zn-TBAPy pyrene-based MOF and BiVO₄/Ti₃C₂ Schottky junction were employed as photocathode and photoanode to form an efficient dual-photoelectrode system. The integration of the cascaded hybridization chain reaction (HCR)/DNAzyme-assisted feedback amplification with DNA walker-mediated cycle amplification strategy realizes femtomolar HPV16 dual-photoelectrode bioassay. Through the activation of the HCR cascaded with the DNAzyme system in the presence of HPV16, plentiful HPV16 analogs are generated that leads to exponential positive feedback signal amplification. Meanwhile on the Zn-TBAPy photocathode, the NDNA hybridizes with the bipedal DNA walker followed by circular cleavage by Nb.BbvCI NEase, producing a dramatically enhanced PEC readout. The achieved ultralow detection limit of 0.57 fM and a wide linear range of 10^-6 nM-10³ nM showcase the excellent performance of the developed dual-photoelectrode system.

Keywords: DNA walker cycle amplification; Dual-photoelectrode biosensor; Feedback amplification; HCR/DNAzyme; HPV16; Zn-TBAPy pyrene MOF.