Functional protein films as interfacial coadjuvants: A synergistic strategy to enhance antibiotic efficacy and suppress biofilms

Abstract

Protein self-assembly at interfaces provides a versatile strategy to engineer functional coatings with applications spanning nanomedicine and advanced materials. Medical tubing-associated infections remain a critical healthcare challenge, driven by biofilm formation and antimicrobial resistance. We present a simple and scalable strategy to address this problem using bovine serum albumin (BSA) amyloid-like coatings applied to polyvinyl chloride (PVC), a widely used biomaterial and glass, as model surface. The coatings were formed by controlled disulfide reduction with dithiothreitol (DTT), yielding robust, adherent films stable under aqueous and mechanical stress. In contrast to earlier syntheses with tris(2-carboxyethyl)phosphine (TCEP), the DTT-based method provides a safer, low-cost route that preserves the physicochemical and anti-biofouling properties of the coatings. Physicochemical characterization revealed that the coatings altered wettability, nanoscale roughness, and interfacial chemistry, resulting in strong suppression of both bacterial (Staphylococcus aureus) and mammalian cell adhesion. Importantly, the anti-adhesive properties originated from the chemical nature of the amyloid aggregates rather than topography alone, emphasizing the role of molecular interactions in modulating cell–surface behavior. While coatings alone suppressed bacterial colonization, residual loads approached infection-risk thresholds; combining the coatings with vancomycin at one-eigth the minimum inhibitory con­ centration achieved complete eradication of sessile and planktonic bacteria. The observed synergy illustrates that functional protein films serve as interfacial coadjuvants, enhancing antibiotic action while minimizing dosage, thereby limiting the development of resistance. Consequently, amyloid aggregates represent a class of self-assembled nanostructures that connect fundamental colloid and interface science with practical biomedical applications.