Engineering Living Biohybrid Electrodes for Renewable Energy Generation and Phenyl Urea Herbicide Biosensing

This study introduces a novel living biophotovoltaic (LBPV) system that simultaneously enables sustainable electricity generation and photoelectrochemical biosensing of phenyl urea herbicides in aqueous environments. A hybrid photoanode was engineered by integrating Leptolyngbya sp. cyanobacteria into a conductive composite matrix consisting of electropolymerized poly(1-(4-(1H-pyrrol-1-yl)phenyl)-2,5-di(thiophen-2-yl)-1H-pyrrole) (P(SNS-Ph-Pyr)), calix[4]arene derivatives, and gold nanoparticles. The cathode was constructed using a P(SNS-Ph-NH2) film immobilized with bilirubin oxidase, enabling enzymatic oxygen reduction. Upon visible light illumination, photosynthetic water oxidation by the cyanobacteria resulted in enhanced photocurrent, while the oxygen byproduct was bioelectrocatalytically converted to water at the cathode. The system demonstrated excellent operational and storage stability. Additionally, the LBPV exhibited a sensitive and selective photocurrent response to diuron and linuron, with detection limits of 0.203 nM and 1.514 nM, respectively. Recovery studies in tap water validated its applicability without pretreatment. The platform showed negligible interference from common environmental contaminants. This work highlights the potential of biohybrid electrodes for dual-mode operation as energy harvesters and herbicide biosensors, offering a cost-effective, stable, and environmentally friendly solution for real-time environmental monitoring.