| The construction of bone tissue engineering scaffold is an important part of bone tissue engineering,which mainly involves the regulation of scaffold composition and structure.Under different preparation techniques,the structure of scaffolds and the optimal composite ratio of components have significant differences.Considering the advantages of scaffold with nanofiber structure for bone defect repair,researchers often introduce fiber structure to enhance the interaction between cells and materials in the design of scaffold structure.In this paper,nano hydroxyapatite/polylactic acid(n HAP/PLA)composite electrospun fiber membrane scaffolds were constructed by electrospinning technology,using polylactic acid(PLA)and nano hydroxyapatite(n HAP)as the materials.The effects of n HAP content on the physicochemical and biological properties of the composite fiber membrane were studied.The relevant research results of the experiment are as follows:(1)The effects of 0-65 wt%n HAP on the morphology,thermal stability,wettability,mechanical properties,and degradability of composite fiber membrane were discussed.When the n HAP content is less than 10 wt%,the fiber diameter has no obvious change.Further increase the n HAP content,the fiber diameter becomes larger.When the n HAP content reaches 65 wt%,the fiber diameter is 1.15μm.In addition,the addition of n HAP increases the fiber surface roughness and defects.The thermal stability of composite fiber membrane increases first and then decreases with the increase of n HAP content.The composite fiber membrane has the highest thermal stability at 10 wt%n HAP content.The addition of n HAP increased the water absorption of PLA fiber membrane,the hydrophilicity of fiber surface and the early degradation rate of composite fiber membrane,and the corresponding performance increase was positively correlated with the content of n HAP.In T_a experiment,with the increase of n HAP from 0 wt%to 3 wt%,the tensile strength and modulus of composite fiber membrane increased by 29.1%and 62.1%compared with pure PLA fiber membrane.When the content of n HAP increased from 3 wt%to 6 wt%,the tensile strength and modulus decreased gradually,but the elongation at break still increased,and reached the highest value at 6 wt%,which increased by 113.2%compared with pure PLA fiber membrane.At this time,the tensile strength and modulus of composite fiber membrane had no significant difference compared with pure PLA fiber membrane.In addition,the tensile test and nano indentation test of T_b showed that the composite fiber film with 6wt%and 10 wt%n HAP content maintained higher tensile strength and elastic modulus than pure PLA fiber film.(2)To explore the effects of 0-20 wt%composite fiber membrane on the proliferation,morphology and differentiation of BMSCs in vitro.The results of cell proliferation experiment showed that 6%n HAP/PLA and 10%n HAP/PLA composite fiber membrane could significantly promote the proliferation and differentiation of BMSCs.Further increasing the content of n HAP to 20 wt%can not promote cell proliferation,morphological spread and differentiation,which is related to the deterioration of mechanical properties of PLA matrix.(3)0-20 wt%n HAP/PLA composite fiber membrane was implanted into rat skull defect by stacking to study the effect of composite fiber membrane on bone repair.The results showed that 6-10 wt%n HAP/PLA composite fiber membrane promoted cell recruitment and infiltration,and improved the osteogenic ability of the material scaffold.Among them,the bone volume/tissue volume(BV/TV)and bone mineral density(BMD)of 6%n HAP/PLA scaffold were 41%and 37%higher than those of pure PLA fiber membrane group,respectively.Although 20%n HAP/PLA composite fiber membrane can further promote cell recruitment and infiltration,it can not provide sufficient mechanical support,resulting in its limited bone repair ability. |
