Cytotoxicity of AgNPs/CS composite films: AgNPs immobilized in chitosan matrix contributes a higher inhibition rate to cell proliferation

In this study, the cytotoxicity of sliver nanoparticle-doped chitosan composite films (AgNPs/CS) was investigated in vitro. In this slow-release system, the doped silver nanoparticles (AgNPs) might modify both the surface properties of the matrix and the ion environment of the surrounding fluid via slow-release, determining the dominant mechanism is of interest. Here, AgNPs (average size is 25 nm) were doped into chitosan (CS) films by mechanical mixing to form a slow-release system. The surface properties and stabilities of the films and the Ag-releasing behavior were studied by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible spectrophotometry, and a weight loss method. The morphology of adhered cells and the survival rate (obtained by both MTT and CCK-8 assays) of human umbilical vein endothelial cells (HUVEC) were employed to describe the cytotoxicity. Using statistical analysis, the following conclusions can be made: the doped AgNPs dispersed in the CS matrix with a polycrystalline structure. During the early erosion, a small amount of debris peeled off and became suspended in the fluid. After that erosion, the composite film became relatively stable, and the doped Ag was slowly released into the fluid. In comparison with the released Ag (either in the peeled debris or dissolved in the fluid), Ag immobilized in the AgNPs/CS films shows a more significant influence on cell adhesion and subsequent proliferation. Film thickness and AgNP content show a synergistic effect on the survival rate of the cell, with the AgNPs content being the key factor.