Research On Low Temperature 3D Printing Collagen/chitosan Scaffolds

Tissue engineering technology realizes the regeneration of tissues and organs by constructing biocompatible scaffolds in vitro,combining cells and growth factors into the body.Different organs/tissues have different functions.Therefore,scaffold design needs to be tissue-specific.In this article,Low-temperature 3D printing technology and freeze-drying technology were combined to prepare highly porous collagen/chitosan scaffolds.Neutralization and cross-linking were used to improve the stability of scaffolds,thus tissue engineering scaffolds with adjustable properties and excellent biocompatibility were prepared.The main content of this article includes:(1)Explore the printability of the ink and determine the concentration ratio of the printable collagen/chitosan ink.The rheology test found that the ink viscosity changes with temperature and the gelation point appears,and as the shear rate increases,it becomes thinner.Therefore,determine the printing temperature(7-10 ℃)and the ratio of ink density suitable for printing(2/2,3/1,3.5/0.5,4/0 group).Therefore,the printing temperature and the suitable ink concentration ratio(2/2,3/1,3.5/0.5,4/0 group)were determined.When the printhead temperature is 8 ℃ and the platform temperature is-10 ℃,the ink comes out most smoothly and the support fidelity is the best.(2)The morphology,stability and mechanical properties of the scaffolds treated with different concentrations of genipin were analyzed to obtain the optimal crosslinking concentration.The results show that the scaffolds cross-linked by 3 m M genipin have good cellular compatibility while maintaining stable three-dimensional network structure.(3)Explore the effect of collagen/chitosan concentration ratio on the morphology and performance of the scaffold.Appearance analysis found that as the proportion of chitosan increases,the pores of the scaffold become denser and more evenly distributed;mechanical tests show that with the increase of chitosan proportion,Young’s modulus and tensile strength increase;degradation performance test showed that the scaffold’s ability to resist collagenase degradation increased with the increase of the ratio of chitosan;the scaffold was inoculated with cells,A large number of cells are found on the surface,inside and bottom.Therefore,it is proved that collagen/chitosan ink has good biocompatibility and the scaffold structure is suitable for cell growth and migration.In conclusion,this article prepared collagen/chitosan inks with different concentration ratios,which have excellent printability.Low temperature 3D printing technology was used to prepare tissue engineering scaffolds with adjustable physical and chemical properties,which had excellent cytocompatibility.Therefore,3D printed collagen/chitosan scaffolds widely used in different tissue engineering fields can lay a foundation for tissue regeneration.