Fabrication of novel carbon dots/cerium oxide nanocomposites for highly sensitive electrochemical detection of doxorubicin

In the current study, carbon dots/cerium oxide (CDs/CeO2) nanocomposites-modified screen printed carbon electrode, SPCE (CDs/CeO2/SPCE) was developed for the highly sensitive and selective detection of doxorubicin (DOX), an anticancer drug. Here, firstly we have synthesized cerium oxide nanoparticles (CeO2NPs) from ammonium cerium nitrate and urea by simple refluxing, and then CDs were synthesized by using taurine (an essential amino acid) via thermal decomposition method. After that CDs/CeO2 nanocomposites have been synthesized with different wt% of CDs (0.5–5 wt%) via a facile hydrothermal method. The synthesized nanocomposites exhibited higher efficiency towards the electrochemical detection of DOX as compared to bare CeO2NPs and CDs by promoting electron transfer reaction at SPCE surface with increasing amount of CDs. The 5 wt% nanocomposite (CDs-5.0/CeO2) showed the highest oxidation response towards DOX (20 μM) at an optimized pH of 5. The cyclic voltammograms revealed that CDs-5.0/CeO2/SPCE sensing system exhibited a linear response (correlation coefficient, R2 = 0.98) between oxidation peak current and DOX concentration in the range of 0.2–20 μM, with a low detection limit of 0.09 μM. Moreover, the modified CDs-5.0/CeO2/SPCE sensor exhibited superior selectivity towards DOX in the presence of common interferents. This work demonstrated that the novel CDs/CeO2/SPCE sensor can be effectively applied to detect DOX in pharmaceutical samples or in biological fluids.