Polytetrafluoroethylene topographies determine the adhesion, activation, and foreign body giant cell formation of macrophages.

Polytetrafluoroethylene (PTFE) is one of the commonly used materials in making various cardiovascular implants. However, the success rates of these implants in several occasions are hindered by unwanted immune responses from immune cells, such as macrophages. In this study, we investigated the response of macrophages with different structures (flat, expanded, and electrospun) of PTFE having varied surface topographies: smooth planar surface (flat PTFE), node-fibrils (ePTFE), and randomly oriented microfibers (electrospun PTFE). The electrospun PTFE showed the least adhesion of macrophages. Also, the morphology of macrophages adhered on electrospun PTFE exhibited minimal activation. The macrophage pro-inflammatory cytokine secretions showed that the lowest level of TNF-α was produced on electrospun PTFE whereas IP-10 was produced in lowest levels on expanded PTFE (ePTFE). The production of IL-6 and MCP-1 cytokines was also dependent on the structure of PTFE that the macrophages interacted with, but in a time-dependent manner. Confocal microscopy images taken at 7, 14, and 21 days showed that the electrospun PTFE resulted in the lowest percentage of macrophage fusion, thus indicating the least possible chance of foreign body giant cell (FBGC) formation. Therefore, this study showed that electrospun PTFE with randomly oriented microfibers can provide reduced adhesion, activation, and FBGC formation of macrophages compared to the smooth and planar surface of flat PTFE and node-fibril structured surface of ePTFE.