Biomaterial topography alters healing in vivo and monocyte/macrophage activation in vitro

The effect of biomaterial topography on healing in vivo and monocyte/macrophage stimulation in vitro was assessed. A series of expanded polytetrafluoroethylene (ePTFE) materials were characterized by increasing average intranodal distance of 1.2 μm (1.2‐ePTFE), 3.0 μm (3.0‐ePTFE), and 4.4 μm (4.4‐ePTFE), but presented consistent surface chemistry with nonporous PTFE (np‐PTFE). Subcutaneous implantation of 4.4‐ePTFE into mice resulted in a statistically thinner capsule that appeared less organized and less dense than the np‐PTFE response. In vitro, isolated monocytes/macrophages cultured on np‐PTFE produced low levels of interleukin 1‐beta (IL‐1β), 1.2‐ePTFE and 3.0‐ePTFE stimulated intermediate levels, and 4.4‐ePTFE stimulated a 15‐fold increase over np‐PTFE. Analysis of cDNA microarrays demonstrated that additional proinflammatory cytokines and chemokines, including IL‐1β, interleukin 6, tumor necrosis factor alpha, monocyte chemotactic protein 1, and macrophage inflammatory protein 1‐beta, were expressed at higher levels by monocytes/macrophages cultured on 4.4‐ePTFE at 4 and 24 h, respectively. Expression ratios for several genes were quantified by RT‐PCR and were consistent with those from the cDNA array results. These results demonstrate the effect of biomaterial topography on early proinflammatory cytokine production and gene transcription by monocytes/macrophages in vitro and decreased fibrous capsule thickness in vivo. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.