Biological 3D Printing Molding Technology And Experimental Study Of Artificial Kidney Organs With A Vascular Network

In the clinical field,due to the small number of sources of organ donation and the increasing demand for various regenerated tissues and organs caused by accidents and diseases,the production of biocompatible regenerated tissues and organs in vitro has become an important field of extensive attention in today’s society.The interleaved vascular network in them is the basis to ensure the survival of cells in tissues and organs and the successful repair of tissues,which requires that the vascular network has sufficient mechanical properties and permeability.Therefore,it has become an urgent problem for scholars at home and abroad to construct a biological organ with a complex three-dimensional vascular network that simulates the natural vascular network of the human body in vitro tissues and organs for promoting the culture of tissues in vitro and improving the efficiency of tissue repair by tissue engineering.In response to the above problems,this article used reactive flow direct writing technology to build an experimental platform that combined software and hardware,including the design and manufacture of semi-flexible coaxial printing nozzles,the integration of the original three-axis motion system and dual extrusion system,the hierarchical simplification of the renal blood vessel network,the editing of the simplified blood vessel network trajectory generation interface through the Visual Studio Code software,the generation of G code that can be recognized by the printing system according to the edited network trajectory and the coordinated control of the action of the experimental platform by reading the code through the host computer that made the extruded alginate hydrogel hollow fibers lay followed the preset network trajectory to successfully prepare different network trajectories.In the preparation of alginate hydrogel hollow fibers,to improve the biological properties of the alginate hydrogel hollow fibers,the IPA component was added to the crosslinking agent to affect the microstructure of the gel through the change of interface polarity.By observing the morphological characteristics and mechanical strength of hollow fibers prepared with different mixing ratios of crosslinking agents,the influence of interface polarity on the structure size(diameter,wall thickness),elastic modulus and penetration effect of hollow fibers was studied.To solve the problem that the bifurcated blood vessel network was difficult to print,different types of internal and external needles were assembled to manufacture the hollow fibers with different diameters which were used as main and bifurcation blood vessels respectively.Ferric chloride was used to keep the hollow shape of the hollow fiber ends for bonding.To obtain the model of the artificial kidney with a vascular network,according to the size and shape of the kidney,the mold of the kidney was drawn by Creo.Gelatin was used as the matrix of the artificial kidney,and the planned network trajectory was embedded in the artificial kidney.The extracorporeal circulation permeation system was designed to simulate the permeation experiment of hollow fiber in the kidney.Six kinds of hollow fibers with different interfacial polarities were analyzed.The vascular network embedded in the artificial kidney was observed.