Chitosan-ZnS nanocomposite hydrogel beads to combat multi-drug-resistant pathogens

The extensive misuse of antibiotics is a key factor for the rapid rise and global spread of multidrug-resistant (MDR) pathogens, which now pose a major threat to public health. This alarming increase in antimicrobial resistance necessitates the development of innovative, biocompatible, and sustainable antimicrobial materials that can overcome the limitations of conventional drug-based therapies. Chitosan (CS) is an excellent candidate for various medical applications; however, its antimicrobial activity alone may be insufficient against broad-spectrum pathogens. Therefore, in this study, ZnS-CS nanocomposite hydrogel beads were successfully synthesized that showed excellent antibacterial, anti-biofilm properties and metabolic activity suppression against both Gram-positive and negative MDR bacterial pathogens. In addition, the hydrogel beads showed significant antioxidant property with minimal hemolytic effect. The morphology of this composite was characterized using SEM and TEM, revealing ZnS NPs sized 8 to 10 nm. The structural properties were evaluated using XRD, Raman, and FTIR spectroscopy. The findings of this study were further supported by in silico analysis, which revealed strong interactions with target proteins, including MecA in Staphylococcus aureus and oxacillin-hydrolyzing class D β-lactamase in Pseudomonas aeruginosa . This ZnS-CS system can be a novel, sustainable, and cost-effective biotherapeutic material with potential applications in combating antimicrobial resistance.