Photo-induced metal-oxide biosensor for analysis of biofluids

Determining the concentration of biomarkers offers insights into the health condition and performance of the body. The majority of the biosensors applied to measuring biomarkers in biological fluids are electrochemical bases; however, these biosensors suffer from several key drawbacks. These include utilizing complex sensing materials to obtain desirable analytical performance, which prevents their practical application; and operation at a relatively high potential, which leads to inaccurate measurements due to the undesired oxidation of non-target molecules. A novel photo-induced chemiresistive biosensor is introduced here that addresses these challenges. A UV-induced ZnO nanorod (NR) chemiresistive biosensor is developed and applied to monitoring lactate and glucose, as model biomarkers in sweat. The detection mechanism of lactate based on its interaction with ZnO NRs is proposed. Furthermore, the effect of the electrode design and operating parameters, including irradiance, radiation wavelength, and applied potential, are evaluated. The highest response, the shortest response time, and complete recovery are obtained at 5.6 mW/cm² irradiance of 365 nm and 0.1 V potential. The results indicate that the developed transduction platform utilizing a simple sensing layer is a promising technique with excellent analytical performance for detecting different biomarkers, thereby paving the way toward the emergence of photo-induced chemiresistive biosensors for real-life applications.