A conductive ormosil encapsulated with ferrocene conjugate and multiwall carbon nanotubes for biosensing application

Highly non-toxic and conductive ormosil composite film was prepared using (3-aminopropyl)triethoxysilane and 2-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane by doping with ferrocenemonocarboxylic acid–bovine serum albumin (FMC–BSA) conjugate and multiwall carbon nanotubes (MWNTs). With glucose oxidase (GOD) as a model enzyme this film could be used to design an amperometric biosensor for glucose determination. The entrapped FMC–BSA conjugate performed excellent redox electrochemistry and the immobilized GOD was highly stable. Under optimal conditions this biosensor was able to detect glucose with a detection limit of 20 μm (S/N=3S/N=3) in the linear range of 0.05–20.0 mm in flow system, which was wider than the batch amperometric mode, with an analysis time of 25 s for each sample. The value of KMapp was 6.6 mm. The proximity of these three components FMC–BSA, MWNTs and GOD enhanced the electron transfer between the film and electrode. This film could be used efficiently for the entrapment of other redox bioactive compounds and biosensing/bioelectrochemical applications.