The study of immobilization of glucose oxidase on hydrophilic-hydropholic silica gel / 西安交通大学学报(医学版)

ABSTRACT

Objective To evaluate the performances of glucose oxidase immobilized on hydrophilic-hydrophobic silica gel, which may be employed to prepare glucose sensor for the determination of glucose in body fluids. Methods The silica gel was prepared from precursors ?-aminopropyltrimethoxysilane (APTMOS) and methyltrimethoxysilane (MTMOS) by sol-gel technique. Glucose oxidase (GOD) was covalently attached to the silica gel via carbodiimide coupling reaction between a carboxylic acid group on enzyme and an amine group of the silica gel under the participation of the linking reagents 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysuccinimide. The performances of immobilized GOD were explored. Results The optimum conditions were obtained as follows: volume fraction of APTMOS 70%, enzyme content given 16 800 U, the temperature of 35 ℃ and buffer pH 5.5. The decrement in the activity of immobilized GOD for the first 2 weeks was less than 10% of its original activity, and the activity of immobilized GOD retained more than 75% of its original activity after 1 month of testing. Six independently prepared immobilized GOD on the silica gel resulted in an average bioactivity of 1 290.9 ?mol?min -1?g -1 with an R.S.D. of 3.4%. The Michaelis constant (K m) of immobilized GOD was 9.1 mmol?L -1. Conclusion Immobilizing GOD on the silica gel via the formation of peptide bonds is an outstanding enzyme immobilization method.