β-Cyclodextrin anchored neem carbon dots for enhanced electrochemical sensing performance of an anticancer drug, lapatinib via host-guest inclusion

Abstract

By utilizing the merits of β-Cyclodextrin and neem carbon dots (C-dots), a simple, eco-friendly, and sensitive electrode material, β-CD functionalized neem carbon dots modified glassy carbon electrode (β-CD@C-dots/GCE) was developed for electrochemical determination of an anticancer drug, lapatinib (LAP). A green and cost-effective approach was adopted for the synthesis of neem carbon dots (C-dots) via the one-pot hydrothermal treatment of leaf extracts of neem (Azadirachta indica). The β-CD was integrated onto C-dots through hydrogen bonding. XRD, FTIR, TEM, fluorescence, UV–Vis, TGA, electrochemical impedance, and cyclic voltammetric studies confirmed the formation of nanocomposite, β-CD@C-dots and used as an electrode material for sensing application. Factors affecting the activity of the sensing interface were investigated by cyclic voltammetry and optimized for sensitive performance. The proposed sensor has displayed the analyte capturing ability (via host-guest inclusion complex formation) as evident from the accumulation of more LAP on the electrode surface. The peak current of LAP was observed to be enhanced by about 30-fold at the modified electrode compared to that at the bare electrode. LAP exhibited three anodic peaks at 0.55 V (Ep, a3), 0.90 V (Ep, a1), and 1.12 V (Ep, a2), and one cathodic peak at 0.47 V (Ep, c1) in phosphate buffer of pH 2.5. Electrode processes were realized under adsorption controlled for peak a1 and diffusion–adsorption mixed controlled process for peak a2, respectively. The synergistic effect of β-CD and C-dots electrode material exhibited a wide linear relationship between the oxidation peak current (peak a1) and concentration of LAP in the range of 1.99 × 10−8 − 8.59 × 10−6 mol L−1, 0.99 × 10−8 − 6.17 × 10−6 mol L−1 and 4.99 × 10−8 − 6.17 × 10−6 mol L−1 for differential pulse voltammetric, square wave voltammetric and linear sweep voltammetric methods, respectively. The lowest LOD value of 1.81 × 10−10 mol L−1 was achieved with the SWV method. The proposed sensor demonstrated satisfactory applicability for the determination of LAP in pharmaceutical formulations and urine samples. Thus, β-CD@C-dots/GCE is a promising and high-performing electrochemical sensor for the determination of LAP.