CeO₂-ZrO₂Nanoparticle-Modified Enzymatic Lactate Biosensors with Reduced Oxygen Susceptibility

In the present work, the development of novel CeO 2 -ZrO 2 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 O 2 -depleted environments. In this regard, CeO 2 -ZrO 2 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 N 2 adsorption methods. The XRD and TEM results confirmed the successful synthesis of CeO 2 -ZrO 2 nanoparticles and a physical surface area of 76.1 m 2 g −1 was measured by BET method. The electrochemical performance results demonstrated that CeO 2 -ZrO 2 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 O 2 -depleted solutions, confirming that the O 2 -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.