Immobilization of Urease Nanoflowers on a Conjugated Polymer Thin Film for Enhanced Catalytic and Optoelectronic...

Enzyme-hybrid nanoflowers (EHN) have attracted substantial interest in biocatalysis due to their high surface area and enhanced catalytic activity compared with free enzymes. Although extensively studied in solution, their integration into solid supports remains limited. Here, thin films composed of urease/Cu²⁺ hybrid nanoflowers and the conjugated polymer (CP) poly-(9,9-dioctylfluorene-co-phenylene) were fabricated by drop-casting and spin-coating to evaluate their biocatalytic and optoelectronic potentials. The films were characterized by ultraviolet-visible, infrared, and fluorescence spectroscopy, as well as transmission electron microscopy. The immobilized nanoflowers retained ureolytic activity and, in some cases, outperformed polymer/bare-urease films. The Michaelis-Menten constant was comparable to values reported for enzyme-hybrid nanoflowers in solution, indicating a minimal loss of substrate affinity upon immobilization. Reusability tests revealed higher performance of nanoflower-based films over three cycles. These findings highlight the potential catalytic and optoelectronic properties of conjugated polymer/enzyme-hybrid nanoflower films, supporting their application in biosensors and functional devices.