Adsorbed serum albumin is permissive to macrophage attachment to perfluorocarbon polymer surfaces in culture

Abstract

Monocyte/macrophage adhesion to biomaterials, correlated with foreign body response, occurs through protein-mediated surface interactions. Albumin-selective perfluorocarbon (FC) biomaterials are generally poorly cell-conducive because of insufficient receptor-mediated surface interactions, but macrophages bind to albumin-coated substrates and also preferentially to highly hydrophobic fluorinated surfaces. Bone marrow macrophages (BMMO) and IC-21, RAW 264.7, and J774A.1 monocyte/macrophage cells were cultured on FC surfaces. Protein deposition onto two distinct FC surfaces from complex and single-component solutions was tracked using fluorescence and time-of-flight secondary ion mass spectrometry (ToF-SIMS) methods. Cell adhesion and growth on protein pretreated substrates were compared by light microscopy. Flow cytometry and integrin-directed antibody receptor blocking were used to assess integrins critical for monocyte/macrophage adhesion in vitro. Albumin predominantly adsorbs onto both FC surfaces from 10% serum. In cultures preadsorbed with albumin or serum-dilutions, BMMO responded similar to IC-21 at early time points. Compared with Teflon AF, plasma-polymerized FC was less permissive to extended cell proliferation. The beta(2) integrins play major roles in macrophage adhesion to FC surfaces: antibody blocking significantly disrupted cell adhesion. Albumin-mediated cell adhesion mechanisms to FC surfaces could not be clarified. Primary BMMO and secondary IC-21 macrophages behave similarly on FC surfaces, regardless of preadsorbed protein biasing, with respect to adhesion, cell morphology, motility, and proliferation.