Using PdO-incorporated MOF-derived sandwich heterostructures for enhanced glucose sensing

Blood glucose concentration plays a vital role in the clinical diagnosis and therapeutic monitoring of diabetes mellitus. Accurate measurement and continuous monitoring of glucose levels are essential for effective disease prevention and management. However, conventional detection methods face significant limitations in practical applications due to poor stability and sensitivity, which hinders the development of long-term continuous glucose monitoring. Herein, we demonstrate novel PdO-incorporated MOF-derived sandwich heterostructures, Co₃O_4-10@PdO₅@CoCu oxides_-400, for glucose sensing. The incorporation of PdO facilitates electron transfer, thereby significantly enhancing the sensitivity of glucose detection. Notably, the unique sandwich structure effectively prevents the leaching of PdO during electrochemical cycling and improves detection stability, enabling the electrode to retain 93.73% of the initial current response after 30 days. The MOF-derived heterostructure, induced by structural transformation in the annealing process, exposes additional active sites and further enhances the electrochemical activity. The experimental results exhibit exceptional sensing performance, with high sensitivities (4.372 mA mM^-1 cm^-2 and 2.615 mA mM^-1 cm^-2). The linear ranges (0.01-1 mM; 1-2.5 mM) and low detection limit (1.49 µM) effectively cover the trace glucose levels typical of human sweat, fulfilling the sensitivity requirements for non-invasive monitoring. Additionally, the rapid response time (2.35 s) ensures immediate signal readout, satisfying the efficiency demands for practical applications. Our work presents a promising approach for developing highly stable and sensitive electrode structures, laying the foundation for future continuous glucose monitoring applications.