Innovative pH-triggered antibacterial nanofibrous coatings for enhanced metallic implant properties

Abstract

Metallic stainless steel bone implants are widely used due to their excellentmechanical properties, low cost, and ease of fabrication. Nanofibrous compositepolymers have been proposed as coatings to promote biocompatibility andosseointegration, thanks to their biomimetic morphology that resembles theextracellular matrix. However, critical practical issues are often overlookedin the literature. For instance, applying coatings to implants with differentshapes presents a significant technological challenge, as does evaluating viablesterilization procedures for hybrid devices containing electrospun polymers. Inaddition, infections pose a risk in any surgical procedure and can lead to implantfailure, there is a need for antimicrobial prevention during surgery as well as inthe short term afterward. In this work, we propose a new and straightforwardmethod for manufacturing nanofibrous composite coatings directly on thincylindrical-shaped metallic implants. Poly(ε-caprolactone) (PCL) nanofiberscontaining bioactive glass microparticles were electrospun onto stainless steelwires and then post-treated using two different strategies to achieve bothhydrophilicity and surface disinfection. To address antimicrobial properties,amoxicillin-loaded Eudragit®E nanofibers were co-electrospun to impart pHselective release behavior in event of a potential infection. The resultingcomposite hybrid coatings were characterized morphologically, physically,chemically, and electrochemically. The antibacterial behavior was evaluated atdifferent media, confirming the release of the antibiotic in the pH range whereinfection is likely to occur. The impact of this study lies in its potential tosignificantly enhance the safety and efficacy of orthopedic implants by offeringa novel, adaptable solution to combat infection. By integrating a pH-responsivedrug delivery system with antimicrobial coatings, this approach not only providesa preventive measure during and after surgery but also addresses the growingissue of antibiotic resistance by targeting specific infection conditions.