Biomaterial Surface Hydrophobicity-Mediated Serum Protein Adsorption and Immune Responses

TLDR

The protein corona that forms on biomaterial surfaces can alter the performance of implanted devices. The study examined how surface chemistry and wettability influence serum protein corona formation and the resulting macrophage innate immune response. Nanothin plasma polymer coatings with four distinct chemical functionalities and varied wettability were fabricated using a substrate‑independent plasma polymerization technique. Protein adsorption was governed by surface chemistry and wettability, with hydrophilic carboxyl surfaces favoring albumin and hydrophobic hydrocarbon surfaces favoring IgG2, leading macrophages to produce anti‑inflammatory cytokines on hydrophilic surfaces and pro‑inflammatory signals on hydrophobic surfaces, thereby linking surface properties to immune responses.

Abstract

The nature of the protein corona forming on biomaterial surfaces can affect the performance of implanted devices. This study investigated the role of surface chemistry and wettability on human serum-derived protein corona formation on biomaterial surfaces and the subsequent effects on the cellular innate immune response. Plasma polymerization, a substrate-independent technique, was employed to create nanothin coatings with four specific chemical functionalities and a spectrum of surface charges and wettability. The amount and type of protein adsorbed was strongly influenced by surface chemistry and wettability but did not show any dependence on surface charge. An enhanced adsorption of the dysopsonin albumin was observed on hydrophilic carboxyl surfaces while high opsonin IgG2 adsorption was seen on hydrophobic hydrocarbon surfaces. This in turn led to a distinct immune response from macrophages; hydrophilic surfaces drove greater expression of anti-inflammatory cytokines by macrophages, whilst surface hydrophobicity caused increased production of proinflammatory signaling molecules. These findings map out a unique relationship between surface chemistry, hydrophobicity, protein corona formation, and subsequent cellular innate immune responses; the potential outcomes of these studies may be employed to tailor biomaterial surface modifications, to modulate serum protein adsorption and to achieve the desirable innate immune response to implanted biomaterials and devices.