Novel Proteomic Assay of Breast Implants Reveals Proteins With Significant Binding Differences: Implications for Surface Coating and Biocompatibility

Background: Silicone elastomer, a ubiquitous biomaterial and main constituent of breast implants, has been used for breast augmentation and reconstruction for over 50 years. Breast implants have direct local and purported systemic effects on normal tissue homeostasis dictated by the chemical and physical presence of the implant. Objectives: Protein adsorption has been demonstrated to be a key driver of local reactions to silicone. We sought to develop an assay and identify the proteins that coat implants during breast implantation. Methods: Wound fluid was salvaged from women who had undergone breast reduction and incubated in contact with the surface of 13 commercially available implant surfaces. An in situ digestion technique was optimized to elute bound proteins. Samples were analyzed on an Orbitrap elite analyser, proteins identified in Mascot Demon and analyzed in Progenesis. Results: A total of 822 proteins were identified, bound to the surfaces of the implants. Extracellular proteins were the most abundant ontology, followed by intracellular proteins. Fibrinogen, a proinflammatory protein and Albumin, an anti-inflammatory protein had significant (P < 0.0001) binding differences between the surfaces studied. Complement C3, C5, and factor H were also shown to have significantly different binding affinities for the implants included in the study (P < 0.05). Conclusions: We have developed a novel assay of breast implant protein binding and demonstrated significant binding affinities for relevant proteins derived from breast tissue wound fluid.