[Ru(dcbpy)₂dppz]²⁺/Fullerene Cosensitized PTB7‐Th for Ultrasensitive Photoelectrochemical MicroRNA Assay

Abstract

A new cosensitization photoelectrochemical (PEC) strategy was established by using a donor–acceptor‐type photoactive material, 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} (PTB7‐Th), as a signal indicator, which was cosensitized with bis(4,4′dicarboxyl‐2,2′‐bipyridyl)(4,5,9,14‐tetraazabenzo[b]triphenylene)ruthenium(II) ([Ru(dcbpy)2dppz]2+) embedded in the grooves of the DNA duplex and fullerene (nano‐C60) immobilized on the surface of DNA nanoflowers for microRNA assay. [Ru(dcbpy)2dppz]2+ and nano‐C60 could effectively enhance the photoelectric conversion efficiency (PCE) of PTB7‐Th as a result of well‐matched energy levels among nano‐C60, [Ru(dcbpy)2dppz]2+ and PTB7‐Th, leading to a clearly enhanced photocurrent signal. Meanwhile, a target recycling magnification technique based on duplex‐specific nuclease was applied in this work to obtain higher detection sensitivity. The proposed biosensor demonstrated excellent analytical properties within a linear detection range of 2.5 fm to 2.5 nm and a limit of detection down to 0.83 fm. Impressively, this cosensitization PEC strategy offers an effective and convenient avenue to significantly improve the PCE of a photoactive material, resulting in a remarkably improved photocurrent signal for ultrasensitive and highly accurate detection of various targets.

Novel D-A-D-Type Supramolecular Aggregates with High Photoelectric Activity for Construction of Ultrasensitive Photoelectrochemical Biosensor

“…Photoactive material, an integral part in photoelectrochemical (PEC) bioanalysis system for signal generation, has aroused great attention in recent years because of the compact relationship with detection sensitivity. − Commonly, the electron donors/acceptors (D/A) existed in electrolyte solution − or in situ generated via biocatalytic reactions − were adopted for improving the PEC signal of photoactive material, which thus inevitably suffered from defects of tedious operation, batch-to-batch variation, and low photon-to-electricity conversion efficiency on account of the separation from photoactive materials. Comparatively, merging electron D/A into photoactive material within a molecule to form the newly self-enhanced materials (denoted as D-A-type) might effectively resolve these issues. − However, the synthesis of these self-enhanced photoactive material was complicated and rigorous. Most importantly, self-enhanced photoactive material in a monodispersed state limited the further improvement of the PEC signal.…”