Research on Cartilage 3D Printing Technology Based on SA-GA-HA

Abstract

Cartilage damage is difficult to heal and poses a serious problem to human health as it can lead to osteoarthritis. In this work, we explore the application of biological 3D printing to manufacture new cartilage scaffolds to promote cartilage regeneration. The hydrogel made by mixing sodium alginate (SA) and gelatin (GA) has high biocompatibility, but its mechanical properties are poor. The addition of hydroxyapatite (HA) can enhance its mechanical properties. In this paper, the preparation scheme of the SA-GA-HA composite hydrogel cartilage scaffold was explored, the scaffolds prepared with different concentrations were compared, and better formulations were obtained for printing and testing. Mathematical modeling of the printing process of the bracket, simulation analysis of the printing process based on the mathematical model, and adjustment of actual printing parameters based on the results of the simulation were performed. The cartilage scaffold, which was printed using Bioplotter 3D printer, exhibited useful mechanical properties suitable for practical needs. In addition, ATDC-5 cells were seeded on the cartilage scaffolds and the cell survival rate was found to be higher after one week. The findings demonstrated that the fabricated chondrocyte scaffolds had better mechanical properties and biocompatibility, providing a new scaffold strategy for cartilage tissue regeneration.

Keywords: 3D bioprinting; additive manufacturing; cartilage regeneration; cartilage tissue engineering scaffold; finite element method.

Figure 1

Printing equipment and pretreatment of cartilage scaffold. (a) Bioplotter printer; (b) 0/90° stacking method; (c) 0/45° stacking method.

Figure 2

(a) 10%HA effect diagram; (b) 13%HA effect diagram; (c) 16%HA effect diagram; (d) hardness comparison diagram of SA-GA and SA-HA-GA support lines; (e) comparison of line elasticity of SA-GA and SA-HA-GA supports.

Figure 3

(a) Bioplotter print head diagram; (b) syringe and syringe grid diagram; (c) mesh quality and local mesh magnification diagram; (d) simulated pressure gradient diagram and local pressure magnification diagram; (e) needle flow rate diagram and local magnification diagram; (f) mixing slurry extrusion process diagram from the needle.

Figure 4

(a) Trend diagram of needle-moving speed and support line width under different pressures; (b) actual print drawing of different bracket line intervals; (c) mechanical stimulation of cartilage scaffold; (d) cartilage scaffolds of different internal structures; (e) comparison of the stent before and after improvement.

Figure 5

(a) Elastic modulus and tensile strength of different stacking mode of cartilage scaffolds; (b) water absorption of cartilage scaffolds; (c) the relationship between degradability of cartilage scaffolds and time.

Figure 6

Cell fluorescence. (a) are cells in the medium under a microscope; (b,c) are fluorescence images of scaffold cells in different fields under a 100× microscope; (d) are fluorescence images of individual cells under a 100× microscope; (e,f) is the image processed by ImageJ software.

Figure 7

Group experiment results. Green represents living cells, while red represents dead cells.