Three-dimensional human skin models infected with Staphylococcus aureus as a tool for evaluation of bioactivity and biocompatibility of antiseptics

Abstract In the light of pandemic spreads of multidrug resistant microorganisms, alternative antimicrobial strategies to the use of antibiotics are in the research focus. As a prerequisite for medical application, the aim of this study was to develop a three-dimensional full skin infection model for evaluating the bioactivity and biocompatibility of antiseptics in application-relevant concentrations. A 3D full skin model consisting of collagen embedded fibroblasts as dermis and a fully differentiated epidermis built from keratinocytes was infected with Staphylococcus aureus. The infected skin models were treated for 24h with the antiseptics polihexanide, octenidine dihydrochlorid, chlorhexidine digluconate, and povidone-iodine. Infection resulted in detrimental effects, strong immune response with increased secretion of lactate dehydrogenase and proinflammatory cytokines as well as increased gene expression levels of proinflammatory cytokines and antimicrobial peptides after 24h. Application of antiseptics protected the skin models from damage due to S. aureus infection while demonstrating good biocompatibility. Best ratio of bioactivity to biocompatibility was observed for polihexanide. Polihexanide also enhanced the innate immune response by increasing the gene expression levels of antimicrobial peptides like human β-defensin 2, human β-defensin 3, psoriasin, and RNAse7. The developed S. aureus infected artificial skin model provides an excellent tool for investigating the response of human cells to microbial infections in a complex 3D structure. Furthermore, the infection model is appropriate for evaluation of bioactivity and biocompatibility of antiseptics. So the model presented in this study is a promising approach for evaluating the mechanisms and effectiveness of new antimicrobial strategies.