Direct Writing Inside Support System To Create Patterned Vascular Networks

The organ–on-chip is an organ physiological micro-system built on the chip,which is based on the micro-fluidic chip,and can be used for simulating complex organ microenvironment in vitro by combining with the cell biology and engineering various methods,and reflecting the main structure and functional characteristics of the human tissue organ.This micro-organ model can help researchers in the most scientific way to graduate the biological behavior of the human body,to determine the response of the human body to drugs or external stimuli,in the life sciences,disease simulation?new drug research and development have a wide range of application value.The core of the organ-on-chip is the vessel structure.At present,the main methods of constructing the vessel structure are stereoscopic lithography and 3D printing.The stereoscopic lithography process is tedious and the structure is mostly two-dimensional,while 3D printing technology has become an effective means to construct complex vascular structure due to its rapid prototyping characteristics,but direct printing can easily cause the deformation of the formed structure.Based on this,a method of printing and constructing vascular system in support system is proposed in this paper.The main contribution of this thesis is summarized as follows.(1)Research on 3D Printing method based on support system.Sodium alginate was used as biological ink,Agarose and gelatin were used as prepolymer matrix,respectively.The effects of relative viscosity of bioink and pre-polymer matrix on the printing behavior,the effect of printing parameters on the microchannel diameter,the thickness of matrix and the concentration of sodium citrate on the formation time of microchannel were investigated.Finally,the microchannel chip structure is printed out under controllable conditions.(2)Study on structure and properties of gel-chip.We prepared pre-polymer matrix,agarose and gelatin as supporting systems,and tested their mechanical properties of the prepared vessel chips under long-term immersion in the medium.In addition,the material diffusion performance is tested to verify that the support system can allow the transport of macromolecular material.(3)Based on the biocompatibility evaluation and the construction of bionic vascular tissue.Firstly,the viability of the cells adhesion,proliferation and growth on the two-dimensional plane of the pre-polymer matrix was verified.Microchannel structures were prepared with agarose and gelatin as supporting systems,and endothelial cells were injected into the channels to investigate the ability of bionic vascular tissue formation,and finally the vascular tissue structure was constructed.