Screen-Printed Organic Electrochemical Transistor: A Protein Immobilization Approach to Detect Aromatic Water Pollutants ^†

Abstract

In response to the environmental threat posed by xenobiotic aromatic pollutants in water, we have developed a compact device that integrates biosensor scaffolds with organic electronics. This innovative approach addresses the challenge of detecting these pollutants, which often lack easily detectable functional groups. Our sensor module is specifically designed for the rapid, economical, reliable, and ultra-sensitive detection of phenol, a common water pollutant. The key to our sensor’s functionality is the biosensing protein MopR, which we have coupled with an organic electrochemical transistor (OECT). To ensure the effective integration of the MopR sensing scaffold, we have optimized graphene oxide (GO) nanosheets to serve as a host immobilization matrix. This MopR-GO immobilized sensor module is then used as the gate electrode in the OECT, with PEDOT:PSS serving as the organic semiconductor material. The resulting OECT sensor offers a conducive microenvironment for protein activity, thereby maintaining high specificity in pollutant detection. It has demonstrated the ability to exclusively detect phenol with minimal sensitivity loss (less than 5% error), even in complex pollutant mixtures and real environmental samples. This fabrication strategy, which effectively combines biological biosensors with organic electronics, holds significant potential for the detection of a wide range of emerging pollutants. It represents a promising step towards more effective environmental monitoring and sustainability.