Selective and sensitive electrochemical detection of doxorubicin via a novel magnesium oxide/carbon dot nanocomposite based sensor

In the present study, we prepared novel and multifunctional carbon dots/magnesium oxide (CDs/MgO) nanocomposites with varied amount of CDs (0.5–5 wt%) via a facile hydrothermal process. The nanocomposites were then utilized for the fabrication of CDs/MgO-modified screen printed carbon electrodes (CDs/MgO/SPCE) for highly sensitive and selective electrochemical detection of the anticancer drug doxorubicin (DOX) using cyclic voltammetry. All the prepared CDs/MgO nanocomposites possess excellent efficiency towards the electrochemical oxidation of the DOX at the surface of SPCE by facilitating electron transfer reaction with increasing concentration of CDs in comparison with bare MgO nanoparticles (NPs) and CDs due to increased electroactive surface area. Besides, the oxidation peak current was also found to be increased with increasing scan rate from 50 to 150 mV/s−1. The CDs-5.0/MgO nanocomposite exhibited maximum oxidation response for the detection of DOX (10 µM) at pH 5 and at a scan rate of 50 mV/s−1. Under the optimized conditions, CDs-5.0/MgO modified SPCE exhibited a linear response for the determination of DOX in the concentration range of 0.1–1 µM (correlation coefficient, R2 = 0.99) with a low detection limit of 0.09 µM. Furthermore, a negligible effect of the common interfering agents validated the superior selectivity of the sensor (CDs-5.0/MgO/SPCE) towards DOX. The suitable linear range, low detection limit, rapid response, and excellent sensitivity of the proposed sensor (CDs/MgO/SPCE) make it a promising tool for the determination of DOX in biological, clinical, and pharmaceutical fields.