The Preparation Of SA/Ge Scaffold And Effects Of ICA On The Proliferation And Secretion Of Chondrocytes By 3D-printing

In the past few years,cartilage defects has been the most common damage in the athletic injury,which easily leads to the formation of osteoarthritis,pains,joint deformities and other symptoms.Damage of articular cartilage is difficult to recovery or self-healing because there are no nerves,blood vessels and lymphoid tissues in the cartilage and cartilage cells have poor regeneration abilities and high maturity.Recently,with rapid advances of the field of tissue engineering,a large variety of functional composite scaffolds have been constructed and exhibited great potential in regeneration of tissue/organ,and repairing of the damaged tissue.In this thesis research,effects of instrument parameters on the preparation of SA/Ge tissue scaffold were firstly studied.The SA/Ge composite gel showed good transparency,moderate viscosity and fluid properties by using 2 g of sodium alginate and 6 g of gelatin as the printing substrate.The printed composite gel scaffold had neat structure,good surface morphology and fine interconnected pores when using the following parameters:0.30-Mpa printing pressure,16-mm/s printing speed,0.8-mm needle diameter and300-?m distance between needle diameter and surface.Secondly,we investigated the properties of the composite scaffold.It had a better thermal stability compared with the single compound scaffolds.The maximum swell percentage of the composite scaffold was up to 713% when it is swollen for 4hours.From the result of the degradation experiment,we found that the crosslink degree was low and calcium ion scross-linked the outside of the SA/Ge scaffold.Through analyzing toxicity of the exact solution from the scaffold,we confirmed that the composite scaffold is non-toxic and biocompatible.Thirdly,we cultivated the C5.18 cells in in vitro.Its growth curve and morphologies were characterized.The cells showed triangular-or polygonal-like shapes.Through staining of Alcian Blue and Safranin,we found that the C5.18 cell shows the ability to synthesize GAG.ICA with the concentration in the range of0.1-100 ?g/m L facilitates the proliferation and secretion of the cells.The concentration of 10 ?g/m L is the optimal value.Last but not least,cartilage cells were seeded on the SA/Ge scaffold in order to observe their growth and secretion effect.The cell adhesion was observed by using scanning electron microscopy(SEM).It was found that cells completely extended after 5 h and connected with each other after 7 h.The CLSM was used to observe the distribution and survival rate of the cells.The majority of cells were found to distribute in the fold of scaffold and holes,while only a few on the surface.Moreover,we found that the amount of cell was decreased with the increasing of scaffold layers.The results of MTT assay and GAG secretion experiment indicated that 10 ?g/m L of ICA was more effective than other concentrations of ICA for the anxoaction,and the proliferation of cells was inhibited when the concentration was closed to 100 ?g/m L.