In this work, a self-supplied electron photoelectrochemical
(PEC)
biosensor for sensitive determination of Pb2+ was established
by utilizing donor–acceptor (D-A)-type PTB7-Th (poly{4,8-bis[5-(2-ethylhexyl)
thiophen-2-yl]benzo[1,2-b,4,5-b′]dithiophene-2,6-diyl-alt-3-fluoro-2-[(2-ethylhexyl)carbonyl]
thieno[3,4-b]-thiophene-4,6-diyl}) as a photoelectric
material coupled with biotin as an efficient signal quencher. Impressively,
compared with the traditional PEC signal quenchers, biotin was first
applied as a PEC signal quencher in this work and it effectively avoided
a cumbersome preparation process, complex DNA sequence design, and
extra reagent assistance and greatly simplified experimental steps,
which could achieve an efficient PEC signal quenching toward PTB7-Th.
In addition, the execution of a DNAzyme-assisted Pb2+ recycling
amplification reaction could release the quencher biotin, leading
to the recovery of the PEC signal, thereby realizing the quantitative
detection of Pb2+. Resultantly, the submitted self-supplied
electron PEC biosensor presented an extensive coverage of assay Pb2+ (50 fM to 500 nM) along with a low determination limit (16.7
fM), which exhibited the advantages of high selectivity and excellent
stability. Importantly, this work provided a powerful alternative
to traditional heavy metal-ion assessment methods and possessed the
potential for application in environment, biomedicine, and food-safety
fields.