Flexible electrochemical sensor with Fe/Co bimetallic oxides for sensitive analysis of glucose in human tears

The construction of uniformly dispersed structure with abundant active sites is crucial for fast electron transport and advancing electrocatalytic reactions. Herein, FexCoyO4-rGO was prepared by depositing Fe and Co bimetallic oxides in-situ on reduced graphene oxide through a simple process combined hydrothermal reaction and calcination. Fe was elaborately introduced into the synthesis of metal oxides to alleviate the aggregation of cobalt oxides and obtain nanocomposites with homogeneously structured and abundant redox sites, and the bimetallic oxides nanomaterials had enhanced electrocatalysis under the synergistic effect. The flexible electrode prepared from FexCoyO4-rGO exhibited excellent detection performance for glucose with a detection limit down low to 0.07 mu M and a sensitivity of 1510 mu M cm-2 mA-1. The adoption of flexible substrates improved the wearability of the electrode and broadened its practicality for detecting biomarkers on the skin surface. The constructed sensor was successfully used in the dynamic analysis of glucose content in tears, and the results were highly consistent with the test outcome of a commercial test kit, demonstrating its application prospects in non-invasive epidermal diabetes mellitus diagnosis.

Automated summary

FexCoyO4-rGO was prepared by depositing Fe and Co bimetallic oxides on reduced graphene oxide. The introduction of Fe effectively alleviated the aggregation of Co oxides, resulting in nanocomposites with homogeneously structured and abundant redox sites. The flexible electrode made from FexCoyO4-rGO showed excellent detection performance for glucose, with a detection limit as low as 0.07 muM and a high sensitivity of 1510 muM cm-2 mA-1. The sensor was successfully used for the dynamic analysis of glucose in tears, demonstrating its potential for non-invasive epidermal diabetes mellitus diagnosis.