Construction And Application Of PLGA Nanofiber Membrane Supported Lung-on-a-chip Microdevice

At present,the traditional PLGA nanofiber membranes were widely used as tissue engineering scaffolds for in vitro cell culture,but this model could not fully simulate the cellular microenvironment with complex biochemical and biophysical factors,and could not reflect the complex physiological or pathological conditions of human tissue and organs.More recently,microfluidic systems have been used in conjunction with tissue engineering approaches and advanced biomaterials,in order to develop more sophisticated platforms to successfully tackle the complexity of human microenvironments.Microfluidic chip technology was an emerging fluid manipulation technology and has been widely used in biology,chemistry,materials and other basic scientific and interdisciplinary fields,and demonstrated significant application prospects in biomedicine,materials science and other aspects.With the continuous development of micromachining technology,especially the rapid development of soft lithography technology,organ chips developed with microfluidic chip technology have attracted much attention.Organ-on-a-chip was a small-sized cell culture device considered to be superior to the animal model for animal toxicity and efficacy evaluation and other aspects.In this work,PLGA nanofiber membrane and PLGA nanofiber/PDMS microporous composite membrane were prepared for the simulation of alveolar respiratory membrane in vitro.The details were as follows:(1)In this study,we took the alveolar microenvironment as a model,and developed a lung-tumor-on-a-chip with poly(lactic-co-glycolic acid)(PLGA)electrospinning nanofiber membrane as the chip substrate and cell culture carrier.The PLGA nanofiber membrane with a controlled thickness(about 3?m)was porous and permeable to molecules.It has good biocompatibility and can be used to simulate the alveolar respiratory membrane.On the chip,cell culture and co-culture of human lung non-small cell lung cancer cell A549 and human fetal lung fibroblast cell HFL1 were carried out and the drug of gefitinib,an EGFR targeted anti-tumor drug,was evaluated.We further probed the possible reasons of A549 cell drug resistance in the presence of HFL1 cells.In addition,we also realized co-culture of three kinds of cells,A549,HFL1 and human umbilical vein endothelial cell(HUVEC),and found that A549 cells could lead to endothelial cell apoptosis or death,and then the occurrence of tumor invasion and intravasation.(2)In this study,we developed a novel poly(lactic-co-glycolic acid)(PLGA)nanofiber/polydimethylsiloxane(PDMS)microporous composite membranesandwiched lung-on-a-chip to perform anti-tumor drug testing.The composite membrane was characterized and the results showed that it was permeable to molecules and thus could be used to study small-molecule drug diffusion.In addition,the microchip could apply perfusion fluids to simulate blood flow under extremely low fluid shear stress,and also could simulate the spherical crown shape of the alveoli by deformation of the composite membrane.Using this chip,we evaluated the anti-tumor drug efficacy of gefitinib in two kinds of non-small cell lung cancer cells,the lung adenocarcinoma NCI-H1650 cell line and the large cell lung cancer NCI-H460 cell line.We further probed the resistance of NCI-H460 cells to gefitinib under normoxic and hypoxic conditions.