Development of the Potentiometric Lactate Biosensor Based on SnO2/ITO Glass Electrode

In this study, a potentiometric lactate biosensor based on a SnO2/ITO glass electrode was fabricated with a simple enzyme immobilization process. The lactate dehydrogenase (LDH) and coenzyme (nicotinamide adenine dinucleotide, NAD(+)) were immobilized on the SnO2 sensing membrane using 3-glycidoxypropyltrimethoxysilane (GPTS). In addition, a solid-state lactate biosensor for potentiometric measurement was proposed. According to the experimental results, the sensitivity of the lactate biosensor based on the SnO2/ITO glass electrode was about 61.5 mV/decade between 6 mM and 40 mM lactate concentrations. Moreover, the relative response of the lactate biosensor maintained 84% of maximum response voltage during 25 times measurements. In application, the lactate biosensor showed obvious response voltage for detection in the dairy, and has advantages as low cost and easy fabrication. Therefore, the lactate biosensor based on the ITO glass electrode was successfully achieved in this study.