The Material Design And Parameters Research Based On Extrusive Additive Manufacturing Of Calcium Alginate Gel

The manufacture of biological scaffold is one of the key technologies in tissue engineering. There are many shortcomings in the traditional process of manufacturing biological scaffolds. In this paper, I design and optimize the calcium alginate gel while studying optimal ratio of crosslinker based on the extrusion method and the effect of extrusion parameters on the formability and forming quality.Finally I achieve the manufacture of the three-dimensional scaffold with complex shape. The following results have been obtained:(1)Build the hardware and software platform based on gel extrusion additive manufacturing.(2)Use the Phan Thien-Tanner(PTT) fluid model to simulate the extrusion process of calcium alginate gel.The simulation results show that the gel extrusion swelling ratio increase while the volume flow rate and the relaxation time increasing.Physical verification shows high simulation accuracy when the feeding amount is small.When studying the velocity field in the simulation results,it shows that when the relaxation time increases, gel in the nozzle exit velocity surge zone is more obvious, gel extrusion nozzle average velocity is smaller.(3)Design the SA-Ca CO3-GDL calcium alginate gel. Study the effect of cross-linking density and cross-linking degree on the properties of the gel, the results show that when the cross-linking density decreases or the cross-linking degree increases, gel speed increases.Increasing crosslinking degree or cross-linking density can lead to higher gel tensile compressive strength and the less water content. The final selection of cross-linking density was 3%, 100% calcium alginate gel cross-linking degree of the extrusion process of experiment.(4)Adopts the upper matching to the scaffold printing experiment, the results show that the nozzle moving speed and extrusion material flow rate impact extrusion of fiber diameter and the size of x-y direction.When the nozzle move speed and extrusion material flow rate increase, the extrusion fiber diameter and forming size increase.(5)Use calcium chloride solution to soak the scaffold to support fully crosslinked afterscaffolds manufacture.The results show the longer soaking time and higher calcium chloride solution concentration make the deformation increase and lighter weight,while the scaffold loss more water content.Using the best materials and parameters to manufacture the three-dimensional support,the shape error can be controlled within 10%, the shape of the stent is better and has a certain mechanical strength, XY. This study reveals that the calcium alginate hydrogel extrusion increased material manufacturing process in material composition and processing parameter of angioplasty and stenting, to further optimize the manufacturing process and more complex three-dimensional scaffold to provide guidance and advice.