Construction Of A 3D Cell Coculture Based Microfluidic Organon-a-chip Bone Disease Model

Organ-on-a-chip is a microfluidic cell culture device based on microfluidic technology and oriented to build a microenvironment that simulates in vivo organs.Compared with animal models,organ-on-a-chip in vitro models have obvious advantages in examining drug absorption,metabolism and toxicity,and are widely used in drug screening,drug development,and in vitro culture models of artificial bionic microenvironments.Organ microarrays also have the advantages of low sample volume,high throughput and high safety.There are already studies on the combined application of multiple organ microarrays to form human microarrays,and their broad application potential has been recognized and valued by many researchers.Among them,due to the high incidence and disability of hormonal osteonecrosis of the femoral head(ONFH),which remains a major clinical challenge,it is necessary to construct a simulated in vitro bone microenvironment to study the pathological process of the disease and to screen effective therapeutic drugs.In this study,microfluidic chip molds were obtained by photolithography,and polydimethylsiloxane,a polymer,was selected as the material for making the chip platform.On the cell culture platform of the prepared organ-on-achip,three main components of bone tissue,namely human-derived bone microvascular endothelial cells(BMEC),human embryonic fibroblasts(HLF),and inorganic hydroxyapatite,were selected for intra-chip "triculture " To construct the bone microvascular structures in the chip.Glucocorticoids were used to treat the vascular structures constructed within the chip to construct an in vitro hormonal osteonecrosis model.And through this model,we verified that both human tumor necrosis factor-α aptamer and self-designed truncated modified aptamer could play a certain degree of protective effect on in vitro simulated osteonecrosis disease.To further validate the vascular effects of the two TNF-α aptamers on hormonal osteonecrosis of the femoral head,a highly sensitive and ideal in vivo vascular effect assay on chicken embryo chorioallantoic membrane(CAM)was used,and the results were consistent with those of the organ microarray.