Development of cholesterol biosensor with high sensitivity using dual-enzyme immobilization into the mesoporous silica materials

作者：Murai Kazuki; Kato Katsuya^*

来源：Applied Surface Science, 2011, 258(5): 1725-1732.

DOI：10.1016/j.apsusc.2011.10.023

• Immobilization
• Enzyme
• Mesoporous silica
• Cholesterol
• Biosensor

Mesoporous silica (MPS) materials with different pore diameters were synthesized by a sol-gel method where organic templates such as cationic surfactant (cetyltrimethylammonium bromide) and triblock co-polymer of (poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol) (Pluronic P123, EO20PO70EO20)), were used. MPS surface was organo-functionalized using a silane coupling reagent (ethyl-, phenyl-, or 3-mercaptpropyltriethoxysilane). Dual-enzyme, cholesterol esterase (10.0 nm x 5.4 nm x 11.0 nm) and cholesterol oxidase (6.8 nm x 8.5 nm x 8.8 nm), was immobilized on MPS materials by physical adsorption. Amount of dual-enzyme immobilized on all MPS materials, having a different pore size (2.7, 6.4, 12.4, 14.7, and 22.6 nm), and organo-functionalized MPS was similar (CE: 1.5 mg/mg silica and CO: 0.01 mg/mg silica). High activity of dual-enzyme was obtained by adjacently immobilizing on MPS materials. Its activity on MPS-2 (pore diameter: 6.4 nm) or MPS-5 (pore diameter: 22.6 nm) showed approximately 60% of native activity. Moreover, dual-enzyme immobilized on MPS with highly hydrophobic organo-functional groups (phenyl-or mercaptopropyl-group) exhibited higher activity than that on no-substituted MPS. Relative activity of dual-enzyme immobilized on organo-functionalized MPS-2 increased from 58% to 93%, under the optimum conditions.

• 出版日期2011-12-15