Argon plasma-modified bacterial nanocellulose: Cell-specific differences in the interaction with fibroblasts and endothelial cells

Unique properties of bacterial nanocelullose (BNC), such as high purity, water retention, nanofibrillar structure and non-cytotoxicity, allow its application in regenerative medicine, particularly for active wound healing and for skin tissue engineering. However, its biological activity is not fully sufficient to be considered a good cell scaffold. This can be enhanced by physicochemical modifications, particularly plasma treatment. In this work, air-dried (AD) or lyophilized (L) BNC samples were modified in a direct current Ar+ plasma discharge (PM). BNC_AD samples showed higher surface roughness, tensile strength and Young's modulus but a lower swelling ratio than BNC_L samples. The swelling ratio of BNC_L samples further increased after PM. The samples were subjected to six-day in vitro cell culture tests with normal human dermal fibroblasts (NHDFs) or human umbilical vein endothelial cells (HUVECs), i.e. cell types important for skin defect healing. NHDFs adhered in higher numbers, by a larger cell spreading area and reached higher cell population densities on PM samples than on unmodified samples. However, in HUVECs, this effect of PM on cell growth was less pronounced or even opposite, especially on mechanically weaker and more swellable BNC_L. At the same time, both cell types preferred mechanically stronger BNC_AD for their adhesion and growth, which was more apparent in HUVECs. The expression of mRNA for markers of cell adhesion and phenotypic maturation in NHDFs (talin, vinculin, CD90) was generally similar on BNC_PM and on tissue culture polystyrene. In HUVECs, the expression of vinculin and PECAM-1 on all BNC samples was lower than on polystyrene, but the expression of KDR (VEGF receptor 2) was higher, especially on BNC_PM. These results indicate cell type-specific differences in the response to various BNC modifications, which must be properly balanced to accommodate various cell types needed for wound healing and skin tissue engineering.