In vitro biocompatibility of copper oxide–chitosan and silver–chitosan nanocomposites for wound-related antimicrobial applications

Copper oxide-chitosan (nCuO-CSs) and silver-chitosan (nAgCSs) nanocomposites are promising antimicrobial materials for wound-related applications. Here, we provide a comparative assessment of their biological effects across three wound-relevant cell models representing immune, epidermal, and connective tissue responses. nCuO-CSs and nAgCSs with metal-to-chitosan weight ratios of 1:0.3, 1:1, and 1:3 were evaluated in human THP-1 macrophage-like cells and HaCaT keratinocytes, and mouse NIH-3T3 fibroblasts. Cytotoxicity, inflammatory cytokine release, cellular association, and effect on fibroblast wound closure were assessed using the MTT assay, ELISA, confocal laser scanning microscopy (CLSM), and the in vitro wound scratch assay. The viability of THP-1 and HaCaT cells was generally unaffected by 24-h exposure to nCuO-CSs and nAgCSs at concentrations up to 20 mg Cu/L and 20 mg Ag/L, respectively. At the same time, the NIH-3T3 fibroblasts were more sensitive, showing reduced viability at 20 mg Cu/L and 10 mg Ag/L. Among the corresponding ionic controls, AgNO₃ was markedly more cytotoxic than nAgCSs, whereas Cu(CH 3 COO) 2 showed cytotoxicity similar to that of nCuO-CSs. The nanocomposites selectively induced IL-8 release in THP-1 macrophage-like cells, whereas IL-1β, IL-6, TNF-α, and IL-10 levels remained unchanged or undetectable, indicating a chemokine response rather than a broad inflammatory activation. CLSM showed cellular association and possible uptake of nAgCSs. Neither nCuO-CSs nor nAgCSs impaired in vitro wound closure under the tested conditions. Overall, nCuO-CSs and nAgCSs exhibited favorable in vitro biocompatibility in wound-relevant cell models, supporting their further evaluation as antimicrobial materials for wound-related applications.