Food-Derived Chitosan–Casein Nanocarriers Enhance the Antibacterial and Anti-biofilm Activities of α-Mangostin

Pathogenic bacteria such as Staphylococcus aureus ( S. aureus ) represent a serious global health concern by forming biofilms that enhance bacterial resistance and persistence in host and environmental niches. Natural compounds such as α-mangostin (α-m) exhibit promising antibacterial potential but low solubility, instability and limited bioavailability restrict their biomedical application. This study prepared α-mangostin-loaded casein–chitosan nanoparticles (α-m NPs) via ionic crosslinking–emulsification under neutral pH conditions and characterized them using dynamic light scattering, scanning electron microscopy, and Fourier-transform infrared spectroscopy, which confirmed efficient encapsulation and structural stability. The results showed that α-m NPs achieved sustained drug release over 72 h and exhibited significantly enhanced bacteriostatic and bactericidal effects. Biofilm assays further revealed that α-m NPs more effectively suppressed extracellular polysaccharide secretion and biofilm formation in MRSA T144 and ATCC 29213 strains. These findings as a whole validate α-m NPs as an efficient antibacterial and anti-biofilm nanosystem and establish a polysaccharide–protein nanoplatform with considerable potential for applications in nanomedicine and anti-infective therapy. Graphical abstract