Flexible Memristive Biosensors for Sensitive Detection of Prostate-Specific Antigen in Biological Environments

In this work, we developed flexible polymerbased memristive-like devices specifically designed for biosensing applications. The fabricated devices consist of two gold electrodes connected by a biocompatible polymeric resistive layer made of poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) and poly(vinyl alcohol) (PVA), on flexible polyimide substrate. To demonstrate the applicability of this novel sensing approach for critical diagnostic applications, we explored the current–voltage (I–V) hysteretic properties for the detection of prostate-specific antigen (PSA). To ensure sensitivity, we harnessed the adhesive properties of 3-glycidyloxypropyl trimethoxysilane (GOPS), to coat the surface of PEDOT:PSS-PVA and then grafted anti-PSA antibodies covalently in the polymeric channel. The layer-by-layer assembly was monitored using electrochemical and current–voltage memristive-like measurements. The specific anti-PSA antibodies assembled on the memristive-like channel enabled PSA detection in undiluted high ionic strength solutions within concentrations ranging from 0.005 to 50 ng/mL. Our thin-film organic memristive-like devices show promise as cost-effective building blocks for memristive-like biosensing of PSA at clinically relevant levels (ng/mL).