Preparation of progressive gradient-aperture osteochondral scaffold and its cytocompatibility evaluation / 中华老年医学杂志

ABSTRACT

Objective:To prepare a progressive gradient-aperture scaffold composed of silk fibroin(SF)-chitosan(CS)-nano-hydroxyapatite(nHAp)for osteochondral repair.Method:The SF solution, CS solution and nHA suspension were mixed in vitro at equal proportions.The progressive gradient osteochondral(OC)scaffold-1(2%), scaffold-2(3%)and scaffold-3(4%)was respectively prepared by using centrifugation, vacuum freeze-drying, chemical cross-linking and three shaping steps.General conditions, porosity, hot water dissolution rate, water swelling rate, compression water swelling rate, water swelling rate after dissolution, mechanical properties, internal structure observation and pore size were measured.Rat bone marrow mesenchymal stem cells(BMSCs)were cultured and the scaffold extract was prepared.The effect of scaffold extract on the proliferation of BMSCs was detected by the cell counting kit-8(CCK-8)method.BMSCs were co-cultured with the scaffold, and the distribution and morphology of the cells around the scaffold were observed.Results:The structure of scaffold was regular in each group and the porosity was more than 80%.Along with the increase of the material concentration, the water swelling rate of the scaffold was decreased gradually( P<0.05). Compared with before compression, the water swelling rate of scaffold-1 was decreased after compression( P<0.05). There was no significant difference in the hot water dissolution rate among all groups( all P>0.05), and the complete dissolution of the scaffold-1, scaffold-2 and scaffold-3 in vitro required 65.9, 60.9, and 73.9weeks, respectively.The elastic modulus of scaffolds in above three groups were 0.0955, 0.1762 and 0.3468 MPa, respectively.The examination results of scanning electron microscope(SEM)showed that the internal structure of scaffold was honeycomb in each group, the pore shape was regular, which showed an inter-connected pore network.The pore distribution was gradually dense and the pore diameter gradually decreased from the cartilage side to the osteogenic side( P<0.05), and the nHAp content increased gradually.The scaffold extract had no obvious toxicity to the growth and proliferation of BMSCs in each group.After BMSCs were seeded on scaffolds and co-cultured for 5 days, the cells grew well without obvious cell death or morphological abnormalities. Conclusions:In this study, a progressive gradient pore size OC scaffold is successfully prepared with good physical properties and biocompatibility, which is expected to be a new bio-mimetic composite scaffold material for repairing OC defects.