Synthesis, Characterization, and Multifunctional Applications of Graphene Oxide Quantum Dots in Environmental Remediation and Biomedical Drug Delivery

This study presents the synthesis and comprehensive characterization of graphene oxide quantum dots (GOQDs) for applications in environmental remediation and biomedical drug delivery. Graphite oxide was initially synthesized using the modified Hummers method, followed by exfoliation via ultrasonication to obtain graphene oxide (GO). The GO was subsequently converted into GOQDs through hydrothermal treatment, yielding nanoparticles with enhanced optical and catalytic properties. The structural, chemical, and optical characteristics of GOQDs were systematically analyzed using UV-Vis spectroscopy, photoluminescence (PL), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR) spectroscopy. The results confirmed the successful formation of GOQDs with distinct absorption and emission properties, making them suitable for photocatalytic applications. In environmental remediation, GOQDs demonstrated high efficiency in the degradation of methylene blue dye, achieving a degradation rate of 94.51% under UV irradiation, highlighting their potential for wastewater treatment. For biomedical applications, GOQDs were functionalized with polyethylene glycol (PEG) to enhance their biocompatibility and stability. Hemolytic assays and MTT cytotoxicity tests confirmed their low toxicity and suitability for drug delivery systems. Furthermore, drug loading studies using tetracycline revealed a high drug loading efficiency (DLE) of 95.8% and a drug loading content (DLC) of 1.23%, underscoring their potential as nanocarriers for targeted drug delivery. This research underscores the versatility of GOQDs, demonstrating their dual functionality in environmental catalysis and biomedical applications. The findings provide a foundation for future studies on optimizing GOQD-based systems for industrial and therapeutic uses.