Tuning catalytic activity and sensitivity in urease‐based thin film biosensors using conjugated polymers and eugenol/biseugenol

Abstract Thin films have emerged as promising platforms for biosensor development due to their versatility and tunable properties. Urease‐based systems are commonly used for urea detection owing to their high specificity and catalytic efficiency. In this study, spin‐coated thin films composed of conjugated polymers and urease were modified with eugenol and its dimeric derivative, biseugenol, to evaluate their influence on film performance. Photoluminescence analyses indicated molecular interactions between eugenol/biseugenol and the conjugated polymer, while enzymatic assays revealed enhanced catalytic activity compared with films containing only the polymer and urease. Capacitance measurements using an electrolyte–insulator–semiconductor (EIS) device demonstrated the films' sensitivity to urea, with the best response obtained for the film without eugenol or its dimeric derivative, biseugenol. These findings suggest that the incorporation of these bioactive compounds affects both the catalytic and sensing behaviors, probably due to modifications in film morphology or diffusion dynamics. © 2026 The Author(s). Polymer International published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.