Surface chemistry of grafted expanded poly(tetrafluoroethylene) membranes modifies the in vitro proinflammatory response in macrophages

Abstract

A series of surface-modified expanded poly(tetra- fluoroethylene) membranes showed varied levels of in vitro macrophage proinflammatory response. Membranes contain- ing a mixture of phosphate and hydroxyl groups (as deter- mined by X-ray photoelectron spectroscopy analysis) stimulate greater macrophage activation than samples con- taining a mixture of phosphate and carboxylic acid segments. The types of proteins that adsorbed irreversibly from serum onto the two samples with the highest and lowest cellular response were investigated using surface-matrix-assisted laser desorption ionisation time-of-flight mass spectrometry. Distinct differences in the number and type of proteins that adsorbed were observed between these samples. A correlation was found between the main protein components adsorbed onto the surfaces and the resulting in vitro proin- flammatory response. This study strongly supports the hy- pothesis that the cellular response is not controlled directly by surface properties but is mediated by specific protein adsorption events. This in turn highlights the importance of better understanding and controlling the properties of intelli- gent surface-modified biomaterials.