Formulation and characterization of pH-sensitive double emulsion sodium alginate/polyvinyl alcohol/graphene quantum dot for efficient quercetin delivery to A549 cells

Abstract This study reports the development of a pH-responsive nanocarrier system composed of sodium alginate (SA), polyvinyl alcohol (PVA), and graphene quantum dots (GQDs) designed for controlled delivery of quercetin (QC), a potent anticancer flavonoid. The incorporation of GQDs significantly enhanced the nanocarrier’s loading capacity, encapsulation efficiency, and stability. Structural characterization using FT-IR and x-ray diffraction confirmed the successful integration of components, while dynamic light scattering and zeta potential analyses indicated a uniform particle size (193 nm) with good colloidal stability (−42.3 mV). Morphological observations revealed predominantly spherical nanoparticles. The optimized formulation achieved up to 84% encapsulation and 47% loading efficiency. In vitro cytotoxicity studies demonstrated enhanced anticancer efficacy against A549 lung cancer cells with reduced toxicity toward normal fibroblast cells. These results suggest that the SA/PVA/GQDs@QC nanocarrier is a promising platform for targeted, pH-sensitive drug delivery with minimized side effects.