Amperometric sensor based on ferrocene-doped silica nanoparticles as an electron transfer mediator for the determination of glucose in rat brain coupled to in vivo microdialysis

In this paper, microdialysis sampling was combined with an enzymatic assay of glucose level in rat brain. A novel amperometric glucose biosensor based on ferrocene-doped silica (FcDS) nanoparticles conjugated with a biopolymer chitosan (CHIT) membrane was developed. These uniform FcDS nanoparticles (about 15 +/- 3 nm) were prepared by a water-in-oil (W/O) microemulsion method and were characterized by TEM and electrochemical technology. The nanosilica surface exhibited high biocompatability and the ferrocene doped inside maintained its high electron-transfer efficiency as a mediator. The glucose biosensor showed a detection limit of 2.0 x 10(-6) mol L-1 with a linear range from 5.0 x 10(-6) to 1.2 x 10(-2) mol L-1. Coupled to microdialysis, it was used to determine the glucose concentration in rat brain. The result was in satisfactory agreement with the literature. (C) 2004 Published by Elsevier B.V.