Andrographolide-Loaded Gold Carbon Quantum Dots and Their Doped Derivatives for Enhanced Hydrophilicity in a Drug Delivery System.

Background/Objectives: Andrographolide (ADG) is a plant-derived compound with promising anticancer properties, but its medical use is limited due to poor water solubility and low bioavailability. This study proposes developing a gold-based nanocomposite drug delivery system, using a simplified synthesis method, to improve ADG's hydrophilicity and enhance its delivery efficiency. Methods: A one-step method was used to synthesize gold nanocomposites with carbon quantum dots (CBQDs) and doped CBQDs acting as reducing and stabilizing agents. These nanocomposites were then conjugated with ADG and thoroughly characterized using multiple structural and spectroscopic techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis), transmission electron microscopy (TEM), Raman spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. Hydrophilicity enhancement was evaluated using NMR-based log P measurements. Biological assessment involved cell viability assays and confocal microscopy studies in PC3 prostate cancer cells, along with the morphological evaluation of human red blood cells. Results: XRD confirmed the formation of crystalline, face-centered cubic gold nanoparticles, while spectroscopic analyses verified successful nanocomposite formation and ADG conjugation. NMR results showed enhanced hydrophilicity of ADG. Biological tests demonstrated that the nanocomposites were compatible with cells. Conclusions: This study presents a straightforward strategy for synthesizing gold-based nanocomposites that enhance the hydrophilicity and delivery potential of andrographolide, supporting their applicability as nanocarrier platforms for anticancer drug delivery.