The immobilization of laccase is important for the fiber optic biosensor based on enzyme catalysis. Copper tetraaminophthalocyanine-ferrorerric oxide [(CuTaPc)-Fe₃O₄ nanoparticle composites were prepared and characterized by IR, field emission gun scanning electron microscopy, XRD, X-ray photoelectron spectroscopy and particle size analyzer. It has been proved that the CuTAPc could disperse spontaneously onto the surface of Fe₃O₄ nanoparticles to form molecular dispersion layer and the Fe₃O₄ nanoparticles were encapsulated by CuTAPc. The nanoparticle composites took the shape of roundish spheres with their mean diameter of about 50 nm. The laccase was immobilized on the surface of the composite by crosslinking with glutaraldehyde, and the immobilized laccase has better stabilities in storage and operation than free laccase. This work provided good basis for developing the fiber optic biosensor with excellent properties.

Key words: CuTAPc-Fe₃O₄ nanoparticle composite, laccase, immobilization, fiber optic biosensor