posted on 2023-12-27, 18:04authored byHuijie Wang, Li Guo, Qingyu Du, Yuting Zhou, Qi Yu, Shuzhen Lv, Sai Bi
Although near-infrared responsive photoelectrochemical
(PEC) biosensors
have less damage to biological components compared to UV–visible
light, they still reveal an inferior response due to the rapid recombination
of photogenerated electron–hole. In this study, a near-infrared-driven
PEC biosensor is fabricated for microRNA (miRNA) detection via integrating
photoelectricity and pyroelectricity. Upon the introduction of target
miRNA-21, the exponential DNA amplifier is triggered based on enzyme-assisted
strand displacement amplification (SDA), releasing multiple Ag2S reporter probes to hybridize with capture probes immobilized
on a CdS-2-mercaptobenzimidazole (2MBI)-modified photoelectrode. As
a result, under the stimulation of NIR, the photoelectric conversion
of Ag2S NPs generates the photocurrents. In addition, due
to the strong hole acceptor ability of MBI, the pyroelectric effect
of CdS-2MBI nanocomposites is enhanced, which generates highly pyroelectro-induced
charge separation efficiency and induces the pyroelectric current
benefited from the spontaneous polarization of CdS-2MBI caused by
the temperature variation under the function of Ag2S nanoheaters.
Impressively, this PEC biosensor has achieved the sensitive and selective
determination of miRNA-21 with a detection limit as low as 54 fM.
Overall, this NIR-driven PEC biosensor based on pyroelectric and photoelectric
effects opens up a new horizon for bioanalysis and early disease diagnosis.