Engineering Cu(OH)₂-AgNP@MWCNT nanocomposite by systematically layering onto a glassy carbon substrate and application as an electrochemical sensor for the analysis of antidiabetic agent metformin

In this study, a novel electrode was engineered by systematically layering a Cu(OH)₂-AgNP@MWCNT nanocomposite onto a glassy carbon substrate. The Cu(OH)₂-AgNP@MWCNT electrode is a sensitive electrochemical sensor designed for the selective detection of metformin, a drug approved by the FDA, primarily used for managing high blood sugar levels in individuals with type 2 diabetes. It is applicable in both clinical and pharmaceutical environments. The characterization of the components was performed utilizing Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). All electrochemical assessments were conducted utilizing cyclic voltammetry (CV), electrochemical impedance spectrometry (EIS), and differential pulse voltammetry (DPV). The electroactive surface area (ECSA) of the working electrode was determined, measuring 0.574 cm² compared to just 0.127 cm² for the unmodified electrode, suggesting greater efficiency and enhanced performance. The sensor exhibited two linear responses for metformin concentrations ranging from 0.02 to 2.0 μM and 2.0 to 100 μM, with limits of detections (LODs) established at 0.014 and 1.52 μM, respectively, and was successfully applied to the determination of metformin in real samples, yielding satisfactory results. The newly developed electrode's performance was evaluated in comparison to the HPLC method using a statistical F-test (P = 0.01). The findings demonstrated that the recovery rates from both methods were comparable and highlighted that the electrode's precision in response actually provides better accuracy than the HPLC technique for analyzing metformin in samples.