Amino-functionalized polymers by gamma radiation and their influence on macrophage polarization

Abstract

Macrophages play a very important role in the wound healing process and in the inflammatory reactions against implanted materials. They polarize into two major phenotypes, pro-inflammatory (M1) and anti-inflammatory (M2) that participate in different biological processes. The aim of this work was to evaluate whether surface grafting of polypropylene (PP) and polytetrafluoroethylene (PTFE) with amino groups, claimed to improve cell adhesion, may modify macrophages polarization. Gamma radiation was applied to obtain PP films with 3%, 6% and 15% nitrogen (N) and PTFE films with 8% N. Amino-functionalized films presented higher Young's Modulus and adsorbed more serum albumin (BSA) than fibrinogen (FB). Balb/3T3fibroblast cells and human macrophages showed enhanced adhesion on functionalized films after 2 h of culture. Macrophages polarization was monitored by means of cytokines secretion for both M1 and M2 markers (IL-6, IL-10, IL-12, IL-1β, INF-γ, TNF-α and metalloproteinase-8). Cytokine levels related to acute inflammatory phase, especially TNF-α, were lower on amino-functionalized films, although the production of anti-inflammatory markers (IL-10) was not different. Overall, amino-functionalization attenuates the secretion of pro-inflammatory cytokines, which may be useful for the correct design of wound healing materials.