Self-Powered Biosensing System with Multivariate Signal Amplification for Real-Time Amplified Detection of PDGF-BB.

A self-powered biosensing system with multivariate signal amplification is designed for the ultrasensitive, highly efficient, rapid-response, and real-time detection of platelet-derived growth factor-BB (PDGF-BB). The biosensing system is composed of enzymatic biofuel cells (EBFCs), a capacitor, a digital multimeter (DMM), and a computer. Using the hybridization chain reaction (HCR), a few single DNA chains are transformed into abundant double-helix chains, which stimulates the reduction of [Ru(NH 3 ) 6 ] 3+ to [Ru(NH 3 ) 6 ] 2+ by electrostatic interaction, corresponding to the "on" state for HCR. As a result, the open-circuit voltage ( E OCV ) is significantly increased in this self-powered biosensing system. When PDGF-BB is present, a binding interaction between the target and the aptamer, i.e., PDGF-BB/Apt, corresponding to the "off" state for HCR, results in a decrease of E OCV . The PDGF-BB concentration is inversely proportional to E OCV , allowing readable, effective, and precise real-time detection of PDGF-BB. The detection limit of the biosensing system is 0.031 pg/mL ( S / N = 3). This strategy provides a promising and powerful tool for the early clinical diagnosis of related colorectal cancer markers.