A novel room temperature ionic liquid sol-gel matrix for amperometric biosensor application

A novel type of ionic liquid (IL) sol-gel hybrid material was developed for amperometric biosensor application. This material was prepared by the hydrolysis of tetraethyl orthosilicate in a 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM+BF4-) solution. The viscous IL prevented the cracking of the sol-gel derived glasses. Horseradish peroxidase (HRP) was immobilized in the hybrid material for the production of an amperometric hydrogen peroxide biosensor. The IL sol-gel enzyme electrodes retained the high activity of HRP and provided long-term stability of HRP in storage. The morphology of the matrix-containing enzyme was characterized by scanning electron microscopy. The characteristics of the biosensor were also investigated by cyclic voltammetry and chronoamperometry. In the presence of ferrocene as a mediator, the biosensor exhibited an excellent stability and sensitivity, and the linear calibration ranged from 0.02 to 0.26 mM with a detection of 1.1 mu M. The apparent Michaelis-Menten constant of the immobilized HRP was 2.0 mM.