Enhanced sensing of bacteria biomarkers by ZnO and graphene oxide decorated PEDOT film

Developing a biofilm biomarker detector and inhibitor will immensely benefit efforts geared at curbing infectious diseases and microbiologically induced corrosion of medical implants, marine vessels and buried steel pipelines. N-Acyl homoserine lactones (AHLs) are important biomarkers gram-negative bacteria use for communication. In this work, we investigated the interactions between three AHL molecules and graphene oxide (GO) and ZnO nanomaterials embedded in conjugated poly(3,4-ethylenedioxythiophene) (PEDOT) film. The results show that PEDOT/GO/ZnO detected AHLs to a considerable extent with adsorption enthalpies of -4.02, -4.87 and -4.97 KJ/mol, respectively, for N-(2-oxotetrahydrofuran-3-yl)heptanamide (AHL1), 2-hydroxy-N-(2-oxotetrahydrofuran-3-yl)nonanamide (AHL2) and (E)-3-(3-hydroxyphenyl)-N-(2-oxotetrahydrofuran-3-yl)acrylamide (AHL3) molecules. The ZnO nanoparticles facilitated charge redistribution and transfer, thereby enhancing the conductivity and overall sensitivity of the substrate toward the AHLs. The adsorption distance and sites of interactions further tuned the charge migration and signal generation by the substrate, thus affirming the suitability of the modeled thin film as a sensor material. Excellent stability and conductivity were maintained before and after the adsorption of each AHL molecule. Moreover, the desorption time for each AHL molecule was calculated, and the result affirmed that the modeled film materials are promising for developing highly sensitive biosensors.