Zinc tetraaminophthalocyanine-Fe3O4 nanoparticle composite for laccase immobilization

Jun Huang, Cheng Liu, Haiyan Xiao, Juntao Wang, Desheng Jiang, Erdan GU

Key Laboratory of Fiber Optic Sensing Technology and Information Processing of Ministry of Education, Wuhan University of Technology, Wuhan, Hubei, P.R. China

Abstract: Zinc tetraaminophthalocyanine-Fe₃O₄ nanoparticle composites were prepared by organic-inorganic complex technology and characterized. It has been proved that the ZnTAPc dispersed randomly onto the surface of Fe₃O₄ nanoparticles to form molecular dispersion layer and there was a relatively strong bond between central zinc cation and oxygen. The nanoparticle composite took the shape of roundish spheres with the mean diameter of about 15 nm. Active amino groups of magnetic carriers could be used to bind laccase via glutaraldehyde. The optimal pH for the activity of the immobilized laccases and free laccase were the same at pH 3.0 and the optimal temperature for laccase immobilization on ZnTAPc-Fe₃O₄ nanoparticle composite was 45°. The immobilization yields and K_m value of the laccase immobilized on ZnTAPc-Fe₃O₄ nanoparticle composite were 25% and 20.1 µM, respectively. This kind of immobilized laccase has good thermal, storage and operation stability, and could be used as the sensing biocomponent for the fiber optic biosensor based on enzyme catalysis.

Keywords: ZnTAPc-Fe₃O₄ nanoparticles composite; organic-inorganic complex; laccase immobilization