Application of thiolated gold nanoparticles for the enhancement of glucose oxidase activity.

Glucose oxidase (GOx) has been covalently immobilized onto chemically synthesized thiolated gold nanoparticles (5-8 nm) via N-ethyl-N'-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS). The lower value of the Michaelis-Menton constant obtained for the immobilized (3.74 mM) GOx compared with that for the free (5.85 mM) GOx suggests significant enhancement in the activity of GOx attached to thiolated gold nanoparticles. The covalently immobilized GOx thiolated nanoparticles exhibit a response time of 30 s, a shelf life of more than 6 months, and improved tolerance to both pH and temperature.