Macrophage cell adhesion and inflammation cytokines on magnetostrictive nanowires

A common problem with medical implants is the biofouling response which can detrimentally damage implants or prevent the implant from function properly. This response is characterized by a thick, frequently avascular, layer of proteins and cells over the implant. To study this problem, we have examined here the adhesion of macrophages and the subsequent expression of inflammatory cytokines on nanowire arrays. We found that the cells on the nanowires typically occupied less area and were more circular than on a flat surface of the same material as the nanowires or tissue culture polystyrene (TCPS) in both the presence and absence of fetal bovine serum. Furthermore, this difference was amplified by pre-coating the surfaces with collagen. The smaller area and circular shape indicated that the cells were not thriving on the surface. Since there was potentially a high amount of cell death on the material, and biofouling is frequently characterized as a chronic inflammation, an eighteen cytokine Luminex (R) panel was performed on the supernatant from macrophages on nanowires, control wafers, and TCPS. As a positive control for inflammation, lipopolysaccharide (LPS) was added to macrophages on TCPS to estimate the maximum inflammation response of the macrophages. Our results indicated that the nanowire structure results in the up-regulation of production in macrophages of inflammatory cytokines such as IL-1 alpha, and IFN-gamma and the down-regulation of IL-6, compared to control wafers. In addition, the nanostructure also increased the production of IL-10 which is known as an inhibitor of inflammation. Our results showed that the nanoarchitecture can disrupt cell adhesion and may lead to an inflammatory response.