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

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.