Microfluidic-based Models Of Human Placenta And Brain For Preliminary Applications

Traditional research methods including cell monolayers and animal models are difficult to recapitulate the development and physiopathology of human tissues and organs.Currently,microtissue engineering and the tissue engineering model have shown promise in the construction of development and disease models that faithfully mimick the human condition.Through the combination of microtissue engineering with stem cell technology and 3D culture,we established in vitro models of human organ development and diseases,to optimize present methods and deeply explore the cellular and molecular mechanisms underlying diseases,providing a powerful platform for basic research,drug testing and clinical therapy.The detailed work in this thesis includes:First,we develop human brain organoids-on-a-chip,which allows for the generation of massive human brain organoids from human induced pluripotent stem cells(hiPSCs)on a microfabricated pillar array in a simple manner.The proposed approach allows for controllable formation of embryoid bodies,and in situ self-organization of brain organoids.These brain organoids were examined to imitate the human brain organogenesis in vivo at early stages of gestation with specific features of neuronal differentiation,brain regionalization,and cortical organization.The "brain organoid-on-a-chip" device combines microfabrication technology with stem cells and developmental biology,providing a simple and robust platform for the study of brain development and neurological disorders.Second,we present a hollow fiber reactor system to generate brain organoids from hiPSCs.A thin and finely adjustable hollow fiber was constructed using a multilayer coaxial laminar flow microfluidic system.As a 3D bioreactor,calcium alginate hollow fiber with ECM allows for the differentiation of brain organoids in a simple and efficient manner.Brain organoids recapitulate key features of human fetal brain in early gestation in terms of cell components,brain regionalization and corticalization.The hollow fiber could provide a new platform to advance stem cell-derived organoid models and their utility in biomedical applications.Third,we present a stem cell-based brain organoid model that allows the exploration of brain development with prenatal alcohol exposure in vitro.With ethanol exposure,brain organoids showed reduced cell proliferation,impaired neural differentiation,increased cell death and the imbalance of excitatory and inhibitory neurons.RNA-seq analysis verified the occurrence of systemic changes in 3D organoids exposed to ethanol.The ethanol-exposed organoids displayed a significant number of modified genes.These new genes may play important roles in aberrant neuronal differentiation or other central nervous system anomalies in individuals with PAE.Forth,we established the placental barrier-on-a-chip to model placental inflammatory responses to bacterial infection.The multilayered design of the microdevice allows the co-culture of placental cells,resembling the functional unit of human placenta.The placental inflammation model on the chip resembled the complicated observations in clinic,including the release of inflammatory mediators,and the adhesion of maternal monocytes.In particular,the transplacental communication were investigated,and implied the potential role of trophoblasts in fetal inflammatory response syndrome in clinic.All these responses are often associated with placental dysfunctions and even abnormal fetal development.