Abstract
Carbon dots are a recently discovered type of nanomaterial with promising applications in drug delivery, catalysis, and biosensing due to their small size, fluorescence, and biocompatibility. This thesis investigates the synthesis of carbon dots using D-penicillamine and citric acid as precursors and studies their interaction with the copper-containing enzyme, tyrosinase. The synthesis method of the carbon dots was microwave-assisted synthesis, and the resulting D-penicillamine carbon dots (DPCDs) were characterized using UV-vis spectroscopy, fluorescence spectroscopy, FTIR, and Zeta potential analysis. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) were also used to determine the size and morphology of the DPCDs. The presence of thiol groups was verified using an Ellman’s assay, demonstrating the retention of D-penicillamine's functional properties in relation to the thiol group. A fluorescence quenching experiment with tyrosinase revealed a concentration-dependent quenching mechanism, yielding a linear Stern-Volmer plot. These results suggest potential applications of DPCDs as biosensors for detecting enzymatic activity and copper (II) ion levels. Given the role of copper in disorders such as Wilson’s disease, these findings indicate that thiol-containing carbon dots may provide both copper chelation and fluorescence-based monitoring, offering potential for future diagnostic and therapeutic applications. Further studies are needed to identify the exact quenching mechanism and expand the applications of DPCDs in biomedical and environmental sensing.