Study On 3D Printing Of Hydrogel Based On Agar-gelatin Particle Support

At present,3D printing technology has been widely used in industrial,construction,biomedical and other fields.With the development of 3D printing technology,3D printing products are gradually approaching thousands of households,ranging from aircraft construction to small 3D handicrafts.3D printing technology is gradually integrated into people’s daily life and scientific research and production activities.Especially in tissue engineering,the application of 3D printing has been rapidly developed in the last decade.3D printing technology in tissue engineering is also known as bio 3D printing technology.The principle is that the biological material is mixed with the target cells,and the desired structure is obtained by using 3D printing technology,and then processed to obtain a biologically active organ model.sodium alginate hydrogel is a commonly used biomaterial for bio-printing because of its good biocompatibility.By adding an appropriate proportion of gelatin,it can enhance the mechanical properties of the gel while meeting the printing conditions.In this paper,two kinds of processes are used to print the hydrogel.The focus of this paper is divided into the following parts:(1)A gel printing platform is available for low temperature extrusion printing and support extrusion printing.The experiment selected agar-gelatin particles as the supporting material,and introduced the preparation process of the supporting materials,and found the suitable ratio of supporting printing agar and gelatin through experiments.(2)The theoretical analysis of the agar-gelatin particle support material used in this paper gives a theoretical basis for forming the support material.The relationship between shear stress and shear rate was measured by a rotary multi-functional rheology,and it was found that the sodium alginate mixed solution used in the experiment was a pseudoplastic-power law fluid.According to the basic equation of the pseudoplastic-power law fluid,an expression of the diameter of the gel extruded fiber is obtained.(3)The judgment model of the power law fluid flow state is given.The flow field of the nozzle is simulated and analyzed by fluent software.The flow velocity distribution,shear force distribution and pressure distribution in the flow field are discussed and analyzed.According to the simulated extrusion pressure and the fiber diameter theoretical formula,the difference between the theoretical value and the simulated value is compared.(4)Through experimental analysis,the advantages of support printing were compared,and the effects of pressure,temperature,nozzle moving speed and nozzle flow path length on fiber diameter were investigated.Through the orthogonal test,the optimal printing parameters for supporting printing were obtained,that is,the moving speed of the nozzle was 8 mm/s,the material holding temperature was 32 ° C,and the input pressure of the syringe was 160 KPa.The experiment set the optimal parameters to print the letter "T" shape,hollow cylinder and triangular prism,verify the feasibility of using agar-gelatin particles as the supporting material,and the accuracy of the experimental parameters.