Sustainable Cu₂O-Carbon Dot Heterointerfaces Derived from Rice Straw for the Anti-Fouling Electrochemical Detection of Vancomycin

Abstract Accurate monitoring of vancomycin (VCM) in clinical settings is essential given its narrow therapeutic window and associated renal toxicity. Current analytical methods, such as high-performance liquid chromatography, are restricted by high costs and complex sample preparation. Electrochemical sensors provide a potentially rapid, cost-effective alternative; however, existing electrode modifications often suffer from sluggish electron transfer and surface fouling. This study addresses these limitations by developing an electrochemical sensor utilizing a hybrid cuprous oxide-carbon dot (Cu2O-CD) composite. The CD component, synthesized from rice straw via a sustainable hydrothermal route, resolves the conductivity and agglomeration issues typical of pure Cu2O nanoparticles. This hybrid architecture creates a selective heterointerface that facilitates charge-transfer kinetics while suppressing electrode passivation. The sensor demonstrates a detection limit of 8.3 nM with a linear range of 0.01 to 2.39 μM. Clinical reliability was verified in human urine samples, with recovery rates ranging from 97.3% to 102.0%, confirming the platform’s potential for practical pharmaceutical monitoring.