Amino Acid-Programmed Biomineralization for Radical-Proximal Enzyme–MOF Interfaces in Electrochemiluminescent Influenza Hemagglutinin Sensing

Electrochemiluminescent (ECL) biosensing is fundamentally limited by inefficient coupling between catalytic radical generation and luminophore excitation. Here, we report an amino acid-programmed biomineralization strategy for constructing radical-proximal enzyme–MOF interfaces under mild aqueous conditions. Serine reconfigures zirconium precursor chemistry to convert a charge-mismatched mineralization process into a charge-adaptive one, enabling biomineralization of cationic horseradish peroxidase (HRP) within PCN-224. The resulting HRP@PCN-224(Ser) exhibits enhanced enzyme loading, preserved protein structure, improved catalytic competence, and pronounced solvent tolerance. Mechanistic analyses indicate that serine-mediated mineralization does more than facilitate enzyme incorporation: it creates a spatially integrated microenvironment in which H 2 O 2 activation and ZnTCPP excitation are more effectively coupled, leading to enhanced ECL transduction. Accordingly, HRP@PCN-224(Ser) produces an approximately 9-fold stronger ECL response than the serine-free counterpart in the presence of H 2 O 2 . Integrated with a dual-aptamer signal-off format, this interface enables ECL sensing of influenza H1N1 hemagglutinin (HA) over 0.1–1000 ng mL –1 with a detection limit of 0.03 ng mL –1, together with good selectivity and satisfactory recovery in serum samples. These findings establish amino acid programmed biomineralization as an interfacial design strategy for enzyme–MOF integration and provide a mechanistically grounded framework for improving ECL bioanalysis through radical-proximal transduction.