A catechol biosensor based on immobilizing laccase to Fe 3 O 4 @Au core-shell nanoparticles

This work is directed towards the synthesis of the magnetic nanoparticle in a core and a gold shell with immobilized of laccase on its surface (Fe O @Au@ Lac). The prepared Fe O @Au@ Lac core/shell nanoparticles are characterized by means TEM, SEM, DLS, zeta potential, UV-Vis, and TGA. Meanwhile, as an example of the applications, Biosensor activity was investigated by using the oxidation of catechol and recording the UV-Vis absorption in the 402 nm wavelength. The biosensor also demonstrated optimum activity at pH 5.0, reaction time at 40 min, and 35 mg the amount of biosensor. Linear response in the catechol concentration range of 5.0-70.0 μM. The limit of detection and the apparent Michaels-Menten constant (K ) of the biosensor were 2 μM and 15 μM respectively.