A novel photoelectrochemical microfluidic chip for multi-index determination of diabetes and its complications

Rapid and accurate monitoring of glucose, lactic acid, pyruvic acid, and 3-hydroxybutyric acid is essential in preventing, diagnosing, and treating diabetes, lactic acidosis and diabetic ketoacidosis. Herein, a novel sensing chip for multi-index determination of diabetes, lactic acidosis, and diabetic ketoacidosis was presented by integrating microfluidic device and photoelectrochemical (PEC) sensor. In order to block the interference from the reductive species in real samples, the PEC sensor was divided into a biocathode and a photoanode, which were installed separately in the upper and bottom layers of the device. The photoanodes were modified with ZnIn2S4 nanoflower as photosensitive material, while enzymes for catalyzing the analytes were immobilized on the biocathodes. The PEC chip displayed wide detection ranges with low detection limits of 0.035 μM, 0.34 μM, 3.3 μM and 0.035 μM for the four analytes (S/N = 3). The chip also demonstrated decent anti-interference capability and reliability in monitoring the four biomarkers in human serum. Furthermore, a household amperemeter was deployed to record the photocurrent signals, which helps to reduce the cost. By replacing the enzyme on the biocathode, the sensing chip could play a role in monitoring a broad range of species.