Research On The 3D Bioprinter Of Blood Vessel

3D bioprinting has shown great promise in the field of tissue engineering,which offers a vital and significant platform for tissue engineering and organ regeneration.Its principle is that the differentiated cells are made into cell suspensions as bio-ink.According to the three-dimensional model of organ or tissue designed by CAD/CAM software,the biomaterials are accurately distributed and stacked layer by layer by 3D bioprinting equipment to obtain the a tissue or organ structure models.Compared with traditional processing methods,3D bioprinting technology has many advantages,such as multi material distribution,complex organization and organ printing.In view of the weaknesses of the traditional 3D bioprinting technology in the printing process,a novel strategy of 3D bioprinting device with encapsulation function is proposed,which includes nozzle printing system,the auxiliary printing system,the environment control system,the nutrient liquid supply system.Research and development of key technologies for printing and shaping is also a challenge for 3D bioprinting technology to successfully apply in vascular printing.In this paper,sodium alginate and gelatin are used as experiment materials,and the manufacturing method of encapsulation printing is put forward,and artificial vascular structure is made based on the multi material 3D biologic blood vessel printing equipment system.The main research contents and achievements are summarized as follows:(1)An auxiliary printing manufacturing method was proposed,and developed a 3D biological vascular printer with multi material printing function.The bioprinter has a dual nozzle structure with independent motion.By independent control of the nozzle,the different biomaterials can achieve on-demand printing and orderly distribution of various biological materials.The auxiliary printing clamp is optimized.The holding device improves the coaxiality of the rotary rod and increases the number of the auxiliary printing devices to achieve synchronous printing of different diameter vessels.We analyzed the effect of full infiltration nutrient solution supply system,semi invasive nutrient solution supply system and on-demand nutrient solution supply system on vessel-like structure printing,and further optimized the nutrient solution supply system.(2)Based on the printing requirement of biomaterial encapsulation,a coaxial printing nozzle is developed,and the material is encapsulated and extruded by coaxial extrusion nozzle.We have developed the novel nozzle structure and optimized the relationship between the structures of each part of the nozzle based on the computational fluid dynamics(CFD)to meet the technological requirements of vascular structure manufacture.The structure of the nozzle is optimized.Through the orthogonal test,the influence of the diameter of the inner diameter,the outer diameter and the travel on the extrusion diameter of the biomaterial is analyzed and the parameters are optimized to realize the controlled extrusion of the material.(3)According to the novel 3D bioprinting device,we have developed the synchronism of tubular structure printing and obtained the suitable theoretical model for vascular manufacture.In order to verify and opertimize the theoretical model,we have adopted the alginate and gelatin as bioink to manufacture the vessel-like structure by 3D bioprinter.The printing of the single layer blood vessel structure is realized by the theoretical analysis and experimental study.We have explored the influence of the printing process parameters on the molding effect.(4)Based on the basic structure of blood vessel,theoretical and experimental studies on multi-layer vascular structure,vascular structure with cell and complex vascular structure were carried out by 3D bioprinter.The theoretical model of multi-layer blood vessel manufacture is obtained,which provides theoretical support for multi-layer vascular structure manufacture.We have manufactured the blood vessel structure and the cell survival rate distributed by 3D bioprinter is 90%,and the complex vascular structure was reconstructed,which proved that the 3D bioprinter has a wide application prospect in the field of blood vessel regeneration.