Hybridization chain reaction for regulating surface capacitance of organic photoelectrochemical transistor toward sensitive miRNA detection

Photon-enabled bioelectronics has long been pursued in modern electronics due to their non-contact, remotecontrol, and even self-powered function interfacing the biological world with semiconductor devices. The debuting organic photoelectrochemical transistor (OPECT) relies on the photovoltage generated by the semiconductors to modulate the channel conductance, which enables light-fueled operation at zero gate bias. Inspired by the insulating nature of macrobiomolecules and surface capacitance mechanism, herein we demonstrate the biological regulation of the surface capacitance towards new OPECT biodetection, which was exemplified by a CdS quantum dots/TiO2 nanotubes photoanode accommodating hybridization chain reaction (HCR) amplification with the target of biomarker miRNA-17. Formation of the non-conducting DNA layer from the miRNA-17oriented HCR could decrease the surface capacitance and increase the corresponding fractional potential drop, shifting the transfer curve horizontally to higher gate voltage and thus producing different drain currents. The OPECT biosensor exhibited a linear relationship with the miRNA-17 concentration on the logarithmic axis in the range from 1 pM. to 10 mu M with a detection limit of 1 pM. This work not only represented a generic methodology of miRNA detection, but also provided a universal mechanism for the operation of advanced OPECT bioanalytics.

Automated summary

Photon-enabled bioelectronics is highly pursued in modern electronics for its non-contact, remote-control, and self-powered function in interfacing the biological world with semiconductor devices. This study demonstrates the biological regulation of surface capacitance for a new organic photoelectrochemical transistor (OPECT) biosensor, providing a generic methodology for miRNA detection and a universal mechanism for advanced OPECT bioanalytics.