Direct visualization of hetero-enzyme co-encapsulated in mesoporous silicas

In this study, a direct visualization technique was applied to the determination of a hetero-enzyme co-encapsulated in pores of mesoporous silicas in solution. Lipase and trypsin modified with fluorescent dyes, used as model enzymes, were co-encapsulated at the same instant in two kinds of mesoporous silicas – FSM-22 and SBA-15 – with pore diameters of 4.2 and 7.1 nm, respectively. A direct observation of composite materials of a hetero-enzyme and a mesoporous silica by a combination of differential interference contrast and fluorescence microscopy revealed that the enzymes were uniformly dispersed throughout the particles of the mesoporous silicas, because of the successful incorporation of the two enzymes. Moreover, lipase and trypsin co-encapsulated in the mesopores maintained their enzymatic activities in hydrolysis reactions of their substrates (triglyceride and casein, respectively), without loss of their enzymatic activities due to structural degradation.