Electro-Biocatalytic Reactivity of Catecholamine at a Lignin Nanoparticle-Tyrosinase Interface.

The electrochemical sensing of similar catecholamines remains challenging due to their overlapping redox behavior and similar reactivity, which often results in poorly selective reaction pathways. Herein, we report a bioinspired tyrosinase electro-catalytic system that enables the modulation of the catecholamine reactivity through the integration of enzymatic oxidation with electrochemical transformation. The biocatalytic platform consisted of electroactive lignin nanoparticles (LNPs) supporting tyrosinase drop cast on the graphene-based screen-printed electrode. The overall reaction included the oxidation of catecholamines to ortho-quinones, followed by nucleophile addition of cysteine under control of the redox environment. Overall, coupling enzymatic catalysis with electrochemical regulation enabled selectivity in the oxidative functionalization of catecholamines, providing a sustainable strategy for tuning reactivity in advanced bioinspired catalytic systems.