Establishment of a cell-based wound healing assay for bio-relevant testing of wound therapeutics

Introduction: Predictive in vitro testing of novel wound therapeutics requires adequate cell-based bio-assays. Such assays represent an integral part during preclinical development as pre-step before entering in vivo studies. Simple scratch tests based on defected skin cell monolayers exist, however these can solely be used for testing liquids, as cell monolayer destruction and excessive hydration limit their applicability for (semi-)solid systems like wound dressings. In this context, a cell-based wound healing assay is introduced for rapid and predictive testing of wound therapeutics independent of their physical state in a bio-relevant environment. Methods: A novel wound healing assay was established for bio-relevant and predictive testing of (semi-) solid wound therapeutics. Results: The assay allows for physiologically relevant hydration of the tested wound therapeutics at the air-liquid interface and their removal without cell monolayer disruption. In a proof-of-concept study, the applicability and discriminative power could be demonstrated by examining unloaded and drug-loaded wound dressings with two different established wound healing actives (dexpanthenol and metyrapone) and their effect on skin cell behavior. The influence of the released drug on the cells ' healing behavior could successfully be monitored over time. Wound size assessment after 96 h resulted in an eight fold smaller wound area for drug treated models compared to the ones treated with unloaded fibers and non-treated wounds. Discussion: This assay provides valuable first insights towards the establishment of a valid screening and evaluation tool for preclinical wound therapeutic development from liquid to (semi-) solid systems to improve predictability in a simple, yet standardized way.