Exploring the potential of silver phosphate nanoparticles as a slow-releasing agent to develop antibacterial and...

The current study explores the potential of silver phosphate (Ag₃PO₄) nanoparticles to enhance the biomedical properties of chitosan films. Ag₃PO₄ nanoparticles of varying sizes and shapes were synthesized by a chemical precipitation method using different precipitating agents (NaH₂PO₄, Na₂HPO₄, and Na₃PO₄). A range of morphologies was achieved for the Ag₃PO₄ nanoparticles, including dodecahedral-like structures and ultra-fine spheres. Specifically, using Na₃PO₄ resulted in the formation of the smallest (20-100 nm) and most uniformly sized nanoparticles. Thus, Na₃PO₄-derived Ag₃PO₄ was selected to prepare nanocomposites with loadings of 3 % and 6 % (w/w). The SEM results indicated no aggregation, demonstrating a uniform distribution of nanoparticles. The hydrophilicity of chitosan remained constant at low nanoparticle content, while a higher nanoparticle content significantly decreased the contact angle from 73.3 ± 1.5° to 61.6 ± 2.1°. Ag₃PO₄-loaded chitosan films consistently released silver ions, which improved the antibacterial performance, achieving inhibition zones of 134.3 ± 7.1 mm² for E. coli and 177.6 ± 9.3 mm² for S. aureus. The MTT assay demonstrated that Saos-II cells maintained normal morphology on nanocomposites, with cell viability at 89.5 ± 0.8 % after incorporation of 6 % Ag₃PO₄ nanoparticles, indicating acceptable biocompatibility. In the current research, we hypothesized that optimizing nanoparticle morphology (i.e., smaller, well-dispersed Ag₃PO₄) could lead to sustained Ag⁺ release and pronounced antibacterial action, while minimizing cytotoxicity, making these nanocomposites promising for wound dressings.