CeO2-ZrO2 Nanoparticle-Modified Enzymatic Lactate Biosensors with Reduced Oxygen Susceptibility

Abstract

In the present work, the development of novel CeO2-ZrO2 nanoparticle-modified sensing platforms was described to address the oxygen dependency of lactate oxidase enzyme-based electrochemical lactate biosensors. Using engineered electrode modification, it was aimed to construct enzymatic lactate sensors capable of working in O2-depleted environments. In this regard, CeO2-ZrO2 nanoparticles were chosen as electrode modifiers due to their high oxygen release and uptake properties. The nanoparticles were prepared using a facile chemical synthesis method and characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman spectroscopy, and N2 adsorption methods. The XRD and TEM results confirmed the successful synthesis of CeO2-ZrO2 nanoparticles and a physical surface area of 76.1 m2 g−1 was measured by BET method. The electrochemical performance results demonstrated that CeO2-ZrO2 nanoparticle-modified biosensors showed high sensitivities regardless of the subjected environments. In contrast to conventional enzymatic lactate biosensors, novel sensor design experienced only a slight drop in the response in O2-depleted solutions, confirming that the O2-susceptibility of the lactate biosensors was diminished significantly. The novel biosensor design showed a high sensitivity of 138.9 ± 1.2 μA. mM−1. cm−2 with the linear range of 2.5 μM–0.6 mM.