Hybrid ZrO₂@CNTs nanocomposite electrodes for ultra-sensitive glucose detection via electrochemical biosensing

A sensitive electrochemical glucose biosensor using ZrO₂@CNTs nanocomposite was developed for real-time metabolism monitoring for athletes. The nanocomposite was prepared by a simple ultrasound-assisted technique, and the glucose oxidase (GOx) was covalently immobilized to improve the biorecognition ability. CNTs treated with acid served as a highly conductive framework, and ZrO₂ nanoparticles can provide structural stability and catalytic performance, thus showing synergistic enhancement of electron transfer kinetics and enzyme loading capacity. A SEM, XRD, FTIR, and XPS comprehensive characterization indicated the successful integration of the nanostructures and attachment of the enzyme. The electrochemical measurements provide an exceptionally wide linear range (20 to 10,040 µM) and a very low detection Limit of 0.17 µM, indicating high sensitivity, selectivity, and excellent stability in the operation of the device. The high specificity was further validated in real samples of human serum and almond juice and agreed well with high-performance liquid chromatography (HPLC) data (recoveries > 98.9%). The GOx/ZrO₂@CNTs-based biosensors provide an encouraging platform for such applications as wearable, real-time monitoring of glucose in athletes and other high-performance sports.