On the role of UV-generated ROS in the desorption of cephalexin from CQDs-based drug-loadable platform

Since the emergence of carbon quantum dots (CQDs), they have attracted much considerations because of their potential applicability in myriad industries. Innumerable efforts have been made to demystify the mysterious world of CQDs from physicochemical view point. In the present work, CQDs were synthesized via a thermal decomposition method following by post-treatment of the sample using ethylenediaminetetraacetic acid (EDTA) as the surface modifier to prepare EDx-CQDs sample where x represents the weight of the utilized EDTA in the study. Then, cephalexin (Cp) with various concentarations were loaded onto the EDx-CQDs to investigate the possibility of Cp adsorption. Cp desorption process was initiated by a 365 nm UV light source. Noteworthily, structural changes of EDx-CQDs before and after UV exposure of drug-loaded sample were assessed by conducting a series of spectroscopic analyses. Transmission electron microscopy (TEM), energy-dispersive x-ray mapping (EDX), ultra-violet-visible (UV-Vis), photoluminescence (PL) spectroscopy, x-ray diffraction (XRD), Raman scattering spectroscopy, and Fourier transform-infrared (FT-IR) analyses were employed to scrutinize physical, chemical, and structural alterations. A combined reactive oxygen species (ROS) mechanism was found to be responsible for the desorption of Cp molecules from CQDs surface. The entanglement of both mechanisms ini-tiates a chain ROS reaction leading to complete detachment of Cp molecules.