A next-generation organ-on-a-chip system for tissue-specific morphogenesis and function

Abstract

Organ-on-a-chip technology has emerged as a powerful tool for modeling human organ function and disease, offering a more physiologically relevant alternative to traditional 2D tissue culture and animal models in recapitulating human physiology. Dual-channel organ-on-a-chip is widely used for modeling various tissue-tissue interfaces, such as blood-brain-barrier, small intestine, and kidney glomerular filtration barrier. However, current organ-on-a-chip devices often rely on thick synthetic membranes, such as polydimethylsiloxane and polycarbonate, to separate their fluidic channels; these materials are orders of magnitude thicker than the basement membranes in human organs. The use of these synthetic membranes results in a permanent barrier between cells and tissues that prevents functional remodeling of extracellular matrix. Such thick membranes also hinder transmembrane crosstalk between cells. Moreover, these membranes have flat surfaces that lack the topographical features and microstructures found in native extracellular matrices that are important for cell fate determination and tissue function.To address this limitation, we explored electrospun silk fibroin as an alternative membrane material for organ-on-chips. Electrospun silk fibroin offers several key advantages, including ultra-thinness, high porosity, mechanical robustness, extracellular matrix-like ultrastructure, and biocompatibility. In this work, we engineered an electrospun silk fibroin membrane that successfully demonstrated the capability to induce podocyte differentiation from human induced pluripotent stem cells. Furthermore, we integrated this silk fibroin membrane into an organ-on-a-chip device, which effectively supports intercellular crosstalk and enables formation of in vivo-like tissue-tissue interfaces. To demonstrate the biological application of the devices, we developed a model of the glomerular filtration barrier to address the urgent need for human-relevant models to study kidney disease, a prevalent global health concern. Using human induced pluripotent stem cell-derived glomerular cells, the organ-on-a-chip device successfully recapitulated the structural organization, filtration function, drug-induced injury, and tissue-specific morphogenesis – formation of endothelial fenestrations – of the glomerular filtration barrier through intercellular crosstalk pathways. This device represents a pronounced advancement in organ-on-a-chip technology by enhancing the biomimicry of tissue interfaces, thereby enabling more accurate modeling of organ function and investigation of the molecular and biophysical mechanisms underlying disease development and progression. The device also demonstrated the potential for translational applications in patient-specific kidney disease modeling and drug testing using patient-derived induced pluripotent stem cell derivatives. Given the versality and biocompatibility of silk fibroin, this approach can also be expanded to model other organ types by coupling with relevant cell types, and multiple organ chips can be connected to create a human body-on-a-chip, enabling the study of inter-organ crosstalk, drug metabolism, metabolic syndromes, and whole-body drug responses. In summary, we demonstrated the successful engineering of a next-generation organ-on-a-chip through integration of an electrospun silk fibroin membrane into an organ-on-a-chip device. The resulting device enabled modeling of in vivo-like tissue-tissue interfaces, facilitating tissue-specific morphogenesis. This innovation provides a versatile platform for modeling organ function, studying disease mechanisms, and testing drugs in a patient-specific manner, with potential applications extending to multi-organ systems and whole-body modeling.