Immobilizing diamine oxidase on electroactive phase-change microcapsules to construct thermoregulatory smart biosensor for enhancing detection of histamine in foods

Aiming at enhancing the biosensing detection of histamine in foods at high temperature, we developed a ther-moregulatory biosensor based on diamine oxidase-immobilized phase-change microcapsules consisting of an n- docosane core, a TiO2 shell, and an electroactive polyaniline/ZnO composite coating layer. The microcapsules exhibit a satisfactory latent heat capacity of over 112 J/g for thermo-temperature regulation. Through an innovative integration of electroactive phase-change microcapsules and biological enzyme in the working electrode, the biosensor obtained a thermoregulatory function through reversible phase transitions by the n- docosane core under high-temperature environments. This enables the biosensor to achieve a higher response sensitivity of 28.57 mu A.mM(-1).cm(-2) and a lower detection limit of 0.473 mu mol/L at the high assay temperatures compared to conventional histamine biosensors. With enhanced electrochemical biosensing performance through in-situ thermo-temperature regulation, the smart biosensor developed in this study has found practical applications for high-sensitive detection and high-accurate quantitive determination of histamine in foods across a broad temperature range.