Imitating the function of glucose oxidase by 3-aminopropyltriethoxysilane modified Cu2O for selective electrochemical glucose sensing

Abstract

Selective detection of glucose in complex biological matrices remains a major challenge for non-enzymatic electrochemical sensors due to interference from co-existing species such as ascorbic acid (AA) and uric acid (UA). Herein, we developed an amine-functionalized Cu₂O electrocatalyst (Cu₂O-NH₂), fabricated via a facile silanization strategy using 3-aminopropyltriethoxysilane (APTES) on Cu₂O octahedron. The introduction of surface amine group effectively suppresses the interference signals of AA and UA by 34.78 % and 46.94 %, respectively, while boosting the glucose oxidation response by 1.8-fold compared with pristine Cu₂O. The resulting Cu₂O-NH₂ sensor showed a wide linear range of 0.00089–1.27 mM with a high sensitivity of 1.6001 mA cm⁻² mM⁻¹, and a low detection limit of 0.89 μM, along with the excellent reproducibility and long-term stability. This customized Cu₂O-NH₂ material ultimately exhibited accurate measurement in actual human serum. Experimental studies and theoretical calculations reveal that the amine groups selectively inhibit the adsorption of AA and UA while accelerating the glucose oxidation kinetics, thus imitating the glucose oxidase-like function. Moreover, the universality of this APTES functionalization strategy was validated across other metal oxides, highlighting its potential to address the selectivity limitations of non-enzymatic sensors and offering new opportunities for the development of non-enzymatic biosensing platforms based on micro- and nano-structured materials.