Synthesis and antibacterial activity of silver doped zinc sulfide/chitosan bionanocomposites: A new frontier in biomedical applications.

Numerous microbial species have caused infectious diseases worldwide, which have become a social burden and a menace to the community. So, there is a need to develop antimicrobial materials and specialized materials for biomedical applications. In the present investigation, we report the simple synthesis, the physicochemical, and antibacterial activity of Silver doped zinc sulfide (ZnS: Ag) capped with Chitosan (CS) to produce ZnS: Ag/CS bionanocomposites (BNCs). The prepared BNCs was evaluated by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) mapping, and UV-Vis spectroscopy. According to the XRD results, ZnS: Ag/CS particles with semicrystalline chitosan/hexagonal ZnS phase structures and an average crystallite size in the range of 30-40 nm was formed. According to FESEM images, a spherical/hexagonal shape of ZnS: Ag particles embedded in the polymeric chitosan matrix. The colony counting method was employed to investigate the antibacterial activity on Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The results revealed that ZnS: Ag particles and ZnS: Ag/CS BNCs have stronger antibacterial activities than pure CS and ZnS. The reduction percentage of ZnS: Ag/CS BNCs against S. aureus and E. coli after 6 h of treatment was >99.9 % and 70 % respectively. These findings suggest that ZnS: Ag/CS BCs not only offer superior antimicrobial properties compared to individual ZnS and CS but also have great potential for advancing biomedical applications due to their enhanced antibacterial performance. The simplicity of the synthesis method and the use of non-toxic materials like chitosan make this a sustainable approach for developing antimicrobial agents, which is a key advantage of this study.