Abstract: In this paper, the differences between silica nanoparticles(SiNPs)and silica microparticles(SiMPs)in the bioeffects of them as carriers for enzyme immobilization were investigated. By choosing bovine liver catalases and horseradish peroxidases as the multimeric enzyme model and monoer enzyme model, respectively, four kinds of immobilized enzymes were obtained through the covalently binding method. After the characterization of above four immobilized enzymes, the following conclusion was stated. Firstly, in the yields of enzyme activity, SiNPs exhibit non-selective excellent biocompatibility to both enzyme models; secondly, SiMPs are superior to SiNPs on thermostability; thirdly, both SiNPs and SiMPs could greatly improve the stability of enzymes in organic solvents; lastly, there is no obvious rule indicated on the optimum temperature of enzyme catalysis, namely, SiNPs are better than SiMPs in the multimeric enzyme model and SiMPs possess much more advantages over SiNPs in the monomer enzyme model. The results would be instructional to the evaluation of nanomaterials' bioeffcts and the application of nanomaterials for enzyme immobilization.

Key words: Silica nanoparticles, Silica microparticles, Carriers for immobilization, Enzyme, Bioeffect