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 µM. The apparent Michaelis–Menten constant of the immobilized HRP was 2.0 mM.