(267e) Electrodeposition of Lysozyme-Silver Antimicrobial Bionanocomposites Onto Stainless Steel Medical Instruments

Design of antimicrobial coatings spans a wide range of product development fields, from food preparation and medical devices to fuel systems and latex paints. In the fabrication of surfaces which inhibit microbial growth, a significant challenge is integrating the bioactive properties of organic antimicrobial molecules with the inorganic surfaces of many instruments and devices. One approach is protein-mediated self-assembly of inorganic macromolecular structures, which incorporates biological molecules into abiotic matrices. For example, the well-known antimicrobial enzyme, lysozyme, has recently been shown to catalyze the formation of inorganic composites and retain its enzymatic activity. Exploiting interactions between biological molecules and inorganic species constitute a viable approach in overcoming biotic-abiotic interface issues inherent to synthesis of antimicrobial coatings. In this study, lysozyme was used to catalyze the precipitation of silver, forming bionanocomposites that exhibit antimicrobial properties. Enzymatic activity of lysozyme-silver nanoparticles was confirmed through lytic assays using Micrococcus lysodeikticus cells. Expanding on these findings, biocomposite films consisting of lysozyme and silver were synthesized in efforts to generate antimicrobial coatings for medical devices and anti-fouling applications. Films consisting of lysozyme and silver were electrochemically deposited onto surfaces of stainless steel surgical blades and syringe needles. Under our experimental conditions, antimicrobial films containing both lysozyme and silver were superior to coatings made when either lysozyme or sliver was absent from electrodeposition solutions, or when a direct current was not applied to solutions. Electrodeposited films were firmly adhered to stainless steel surfaces, even after extensive washing, and retained antimicrobial activity. In addition, the efficacy of coatings was tested by subjecting blades and needles to an in vitro lytic assay designed to mimic the normal application of the tools. Coated blades and needles were used to make incisions and stabs, respectively, into agarose infused with M. lysodeikticus cells. Cell lysis was seen at the site of the incisions and stabs, demonstrating that antimicrobial activity is transferred into the media, as well as retained on the surface of the blades and needles. Results show that a one-step electrochemical deposition can be used to prepare antimicrobial biocomposite coatings.