Bioactivity Determination of Recombinant lysostaphin Immobilized on Glass Surfaces Modified by Cold Atmospheric Plasma on Staphylococcus aureus

Introduction: Staphylococcus aureus is a source of nosocomial infections and one of the significant concerns in patients with indwelling devices. Lysostaphin is a bacterially produced endopeptidase with a unique activity on S. aureus. Plasma, the fourth state of the material, consists of charged ions, free electrons, and activated neutral species. Biomedical applications of cold plasma are rapidly growing due to its capacity to treat heat-sensitive objects such as polymeric materials and biological samples. It activates surfaces by etching them to stabilize proteins. The direct effect of cold atmospheric plasma on the eradication of microorganisms have been investigated. However, there is no report on immobilizing antibiotic agents. Methods: In this study, the lysostaphin protein was expressed and purified using Ni-NTA column, then the purified enzyme was immobilized on glass surfaces pretreated with cold atmospheric plasma for 150 s, 200 s, and 300 s. The antimicrobial activity of immobilized lysostaphin on S. aureus was approved by in vitro analysis. Results: The 300 s plasma treatment confirmed to be the best time arrangement for more lysostaphin immobilization, shown by Atomic Force Microscopy. Conclusion: Our results showed that passive adsorption to the treated surface does not affect the structure and subsequent antimicrobial function of the recombinant protein compared to the standard proteins.