Visible Light-Driven Self-Powered Device Based on a Straddling Nano-Heterojunction and Bio-Application for the Quantitation of Exosomal RNA.

Abstract

This paper reports the design and fabrication of a self-powered biosensing device based on TiO₂ nanosilks (NSs)@MoS₂ quantum dots (QDs) and demonstrates a bioapplication for the quantitative detection of exosomal RNA ( Homo sapiens HOXA distal transcript antisense RNA, HOTTIP). This self-powered device features enhanced power output compared to TiO₂ NSs alone. This is attributed to the formation of a heterojunction structure with suitable band offset derived from the hybridization between TiO₂ NSs and MoS₂ QDs, i.e., the straddling (Type I) band alignment. The sensitization effect and excellent visible light absorption provided by MoS₂ QDs can prolong interfacial carrier lifetime and improve energy conversion efficiency. This self-powered biosensing device has been successfully applied in quantitative HOTTIP detection through effective hybridization between a capture probe and HOTTIP. The successful capture of HOTTIP leads to a sequential decrease in power output, which is utilized for ultrasensitive quantitative HOTTIP detection, with a linear relationship of power output change versus the logarithm of HOTTIP concentration ranging from 5 fg/mL to 50 000 ng/mL and a detection limit as low as 5 fg/mL. This TiO₂ NSs@MoS₂ QDs-based nanomaterial has excellent potential for a superior self-powered device characterized by economical and portable self-powered biosensing. Moreover, this self-powered, visible-light-driven device shows promising applications for cancer biomarker quantitative detection.