Development of a contraction-free, vascularized full-thickness skin-on-a-chip platform for modeling immune responses...

The establishment of physiologically relevant in vitro skin models remains a fundamental challenge in tissue engineering, particularly concerning reliable drug screening platforms. Despite advances in conventional skin equivalents, matrix contraction has substantially impeded long-term experimental studies. Here, we report a novel non-contracting full-thickness skin equivalent incorporating a microvascular-like endothelial network that addresses these constraints. We employed an engineered porous scaffold that limits matrix contraction and supports development of a microvascular-like network. The porous support eliminated macroscopic contraction (100% area retention vs. 11.9% previous), enabling extended dermal maturation and stable long-term ALI culture. Sequential seeding of human umbilical vein endothelial cells (HUVEC), dermal fibroblasts, and keratinocytes produced a stable, interconnected vascular architecture. Network identity and perfusability were confirmed by CD31/CD144 immunofluorescence and fluorescent microsphere perfusion. This configuration permits prolonged culture stability and reproducible pharmacological assessments. The model's efficacy was evaluated through an atopic dermatitis (AD) pathological model. Upon pro-inflammatory cytokine stimulation (IL-4, IL-13, IL-22), comprehensive analyses revealed significant alterations in stratum corneum morphology, epidermal protein expression, and atopic-specific biomarkers (IL6, TSLP, CA2). Cytokine-dependent recruitment and dermal localization of HL-60 cells, demonstrated superior physiological relevance compared to avascular models. This platform represents a significant advancement in skin tissue engineering, providing a sophisticated tool for investigating dermatological pathologies and pharmacological responses, while offering a viable alternative to traditional animal testing.