Advanced Fabrication Protocol of an Elastic Porous Membrane for Organ-on-a-chip Applications

potential to accelerate drug discovery, reduce development costs, and provide more predictive data for personalized medicine 3 .The majority of MPS models require a basement membrane as a structural component to form and recapitulate a functional cellular unit on a biocompatible, flexible, and porous membrane.This membrane serves as a physical substrate for extracellular matrix (ECM) deposition, supporting the adhesion of anchorage-dependent cells while providing directional cues for cell polarization.These cells require attachment to a substrate or extracellular matrix for survival, proliferation, and normal function, and include most epithelial and endothelial cells commonly used in organ-on-a-chip systems.Moreover, the membrane establishes a defined boundary between adjacent tissue compartments, permitting the coculture of multiple cell types, such as epithelium and endothelium, under distinct microenvironments, including differential oxygenation.Membrane porosity enables molecular transport, supporting physiologically relevant processes including absorption 4, 5 and efflux 6 , as well as cell transmigration across epithelial or endothelial barriers [7][8][9] .Membrane elasticity also allows it to function as a biomechanical interface, transmitting dynamic strain that mimics organ-specific motions such as intestinal peristalsis 10,11 or lung breathing 12 .The ability to model these structural, biochemical, and mechanical features positions the porous membrane as a key regulator of tissue organization and function in MPS platforms.Therefore, rapid and reproducible fabrication of high-quality porous PDMS membranes is essential to advancing organ-on-a-chip devices for next-generation biomedical research and drug development.Various materials are used for porous membrane and microfluidic device fabrication, including polycarbonate (PC) 13,14 , polyethylene terephthalate (PET) 15 , polytetrafluoroethylene (PTFE) 16 , poly(methyl methacrylate) (PMMA) 17 , cyclic olefin copolymer (COC) 18 , and polydimethylsiloxane (PDMS) 7,10,[19][20][21] .Among these, PDMS is most widely utilized owing to its