HIGH-THROUGHPUT 3D MICROFLUIDIC SKIN-ON-A-CHIP PLATFORM FOR COSMETIC COMPOUNDS TESTING

Here we present a microfluidic skin-on-a-chip platform engineered with precise control over pore size and Laplace pressure, enabling testing of various cosmetic compounds' effects on skin health markers such as collagen, elastin, melanin levels, and autophagy activation.The escalating demand for ethical alternatives to animal testing in cosmetic research, driven by regulatory changes and public concern, necessitates advanced in vitro models that closely replicate human skin physiology.Despite the inherent challenges in replicating the thin, delicate layers of human skin in vitro, our microfluidic skin-on-a-chip platform overcomes these obstacles to deliver a structurally and functionally accurate model.Our refined microfluidic skin-on-a-chip platform employs microfluidic liquid patterning and high-resolution Digital Light Processing (DLP) 3D printing technology to construct a tri-layer skin model.This model facilitates cosmetic and drug testing, potentially allowing for the creation of customized skin models using human-derived cells.Additionally, the model includes 96 pores, each serving as a distinct testing unit for high-throughput experiments.The core innovation of our approach lies in the microfluidic patterning method that controls the distribution and behavior of the liquid within the chip through precise manipulation of Laplace pressure, dictated by adjustments in pore size and contact angle.According to the Young-Laplace equation, the capillary pressure difference across the air-liquid interface facilitates the controlled deposition and maintenance of distinct cellular layers, thereby creating an environment that mimics in vivo skin conditions.Initially, we patterned dermal fibroblasts embedded within a fibrin gel matrix in the second layer, followed by the precise placement of keratinocytes and melanocytes atop this structure.Beneath these layers, a dedicated channel ensures continuously media supply, which is crucial for maintaining cell functionality and longevity by facilitating nutrient availability and waste removal.This model adeptly simulates the structural and functional complexities of human skin's epidermal and dermal layers.Our platform enables in-depth research on cosmetic ingredients by facilitating precise observation of cellular responses to various compounds.The advanced microfluidic skin-on-a-chip technology has demonstrated exceptional capabilities in simulating human skin for cosmetic testing, providing an accurate, ethical, and costeffective alternative to traditional animal testing methods.This platform has been successfully employed to evaluate the efficacy of various anti-aging and skin-whitening agents, including Argireline, Eperuline, Beach Vitex, Saururus Chinensis, Dermagenist, and Chronoglow.These compounds were assessed for their impact on key skin health markers, including collagen and elastin for improved skin elasticity, and melanin for reduced pigmentation.Additionally, tests on autophagy activation, a cellular degradation process crucial for cell renewal and longevity, revealed enhanced LC3 expression, underscoring the potential of these agents to improve cellular resilience and extend cell lifespan.This highlights the platform's utility in developing new skincare solutions that are both effective and scientifically substantiated.This model supports global regulatory trends advocating for reduced animal testing and more humane research methods.By closely mimicking human skin, it enhances our understanding of skin biology and improves methods for cosmetic testing and dermatological research.The skin-on-a-chip technology, integrating advanced engineering with biological insights, sets a new standard for in vitro skin models, significantly advancing both dermatological research and ethical cosmetic science.