Capacitive Sensor-based Artificial Stratum Corneum for Skin Irritating Assessment of Botanical Insect Repellent Products and a De-irritation Formulation.

While plant-based insect repellents are increasingly favored as eco-friendly and biocompatible alternatives to synthetic products like N,N-diethyl-meta-toluamide (DEET), they are not inherently free from dermatological risk. Many botanical ingredients, including citronella, lemongrass, and eucalyptus oils, contain bioactive compounds known to cause skin irritation or allergic reactions in sensitive individuals. Despite their widespread use, there remains limited research on their irritation potential using real-time, in vitro testing platforms. The objective of this study was to evaluate the skin irritation potential of commercial plant-based insect repellents and to investigate the mitigation effect of a micellar solution-based formulation using a novel electronically artificial stratum corneum (eASC). This study employed a capacitive biosensing system integrated into a lanolin-based lipid membrane to detect real-time changes in interfacial capacitance-an indicator of barrier disruption-upon exposure to various repellent products. Results demonstrated that certain plant-based repellents significantly altered membrane capacitance, indicating barrier disruption consistent with irritation. However, micellarization with PEG-40 hydrogenated castor oil markedly attenuated the dielectric response, suggesting reduced irritation potential. These findings underscore the importance of formulation strategy in reducing adverse skin reactions and validate the eASC platform as a cost-effective, indicator-free alternative to conventional irritation assays. This method provides a promising approach for rapid screening during product development and regulatory evaluation of topical botanical products.