Nanomaterial Penetration in Compromised Skin: A Critical Review of Toxicological Risks and Knowledge Gaps

Nanomaterials have revolutionized dermatology by enhancing drug delivery, skincare, and cosmetic applications. However, their increasing utilization raises concerns 
regarding potential toxic effects, particularly in compromised skin. This review addresses knowledge gaps in nanomaterial penetration mechanisms, toxicological risks, and safety evaluations in damaged or diseased skin. Factors influencing absorption, including particle size, surface charge, dissolution properties, and skin conditions, were analyzed. Comparative studies on healthy versus compromised skin and in vivo/in vitro toxicity methodologies were examined. Compromised skin exhibits significantly higher permeability to nanomaterials than healthy skin. Specific nanoparticles, such as metal oxides, quantum dots, and polymeric types, accumulate in skin layers, potentially inducing oxidative stress and inflammation. Despite advancements, critical gaps remain in understanding nanomaterials' long-term effects and systemic toxicity in compromised skin. Further research is necessary to establish predictive risk models and safety protocols for dermatological applications.