Distribution of Immobilized Enzymes on the Surface and into the Mesoporous Silica Particle

Abstract

Mesoporous silica particles are used for immobilization of enzymes in order to increase enzyme stability, facilitate product purification and reuse of enzyme. An important question is how the immobilized enzymes distribute on the surface or inside the pores of silica particles, the difference between porous particles and non-porous particles can be helpful to investigate the effect of pores on the capacity of loading for the particles. Here, we examine the immobilization of lipase in three different types of mesoporous silica particles with different pore size but the same diameter, 5 µm. The hydrodynamic radius of lipase id 2.25 nm; while the radius of the silica particle pores is 12nm, 6nm and 2nm. In this research secondary ion mass spectroscopy (SIMS) is used as a novel method to monitor the distribution of immobilized enzymes. Also high resolution fluorescence microscopy is used to compare with SIMS results. The immobilization is followed by recording the fluorescence from epicocconone, a dye binding to the enzyme.