Preparation Of Controlled Release Icariin-β-Tricalcium Phosphate Composite Scaffold In Study Of Osteonecrosis Of Femoral Head

Objective:To evaluate the forming process of beta-tricalcium phosphate scaffold composited with icariin(ICA),and understand its mechanical and biological properties,in order to verify the feasibility of the beta-tricalcium phosphate composite with icariin as the implant materials for avascular necrosis of the femoral head.Methods:Three-dimensional porous scaffold model was designed by Solidworks modeling software.And then it used extrusion of 3D printer to produce the porous beta tricalcium scaffolds,which obtained the porous β-tricalcium phosphate scaffold after drying and sintering.The microscopic structures were observed by scanning electron microscope(SEM),the porosity and water absorption were measured by Archimedes method,and the compressive strength of the material was tested by the electronic universal material testing machine.The X-ray diffractometer(XRD)was used for phase analysis.The sustained-release microspheres of Icariin/poly(lactic-co-glycolic acid)(PLGA/ICA)containing 10-5M Icariin were prepared by ultrasonic emulsification solvent dialysis method,and N,N-Dimethylfor-mamide/poly(lactic-co-glycolic acid)(PLGA/DMF)andN,N-Dimethylformamide/Icariin(ICA/DMF)were mixed under ultrasonic conditions in an ice bath.Then,1%PVA solution was added to form a double emulsion,which was placed in a dialysis bag overnight to remove DMF,and obtained ICA/PLGA sustained-release microspheres by centrifuging,washing and lyophilizing.The microspheres were combined into the porous scaffolds by concussion and centrifugal perfusion.Then we can obtained icariin-p-tricalcium composite scaffold by added to 10%gelatin,centrifuged again and then freeze-dried.The microstructure,drug loading rate and entrapment efficiency of the drug-loaded microspheres were measured and the drug release experiment was carried out in vitro.Results:The appearance size of β-tricalcium phosphate scaffold prepared by 3D printer is about 11mm × 11mm × 6mm,the pore spacing is 600μm,and the macroscopic pore structure is regular and the pore connectivity is good.By tested,the porosity of the porous scaffold was(66.93 ± 2.84)%.SEM observation showed that there were many micro pores on the surface of the scaffold,and the pore distribution was uniform and the pore connectivity was better.X-ray diffraction analysis of β-TCP scaffolds power showed that there was no phase transition before and after sintering.Though testing compressive strength of β-TCP scaffold after sintering,the maximum compressive strength of the scaffolds was(2.98±0.78)MPa,and addition of the nano ZnO,the maximum compressive strength was reached(8.95 ± 0.29)MPa,while the mechanical properties reached the cancellous bone.The apparence of ICA/PLGA microspheres was light yellow powder,SEM showed microspheres were spherical,and the particle size was about1～4μn,evenly distributed on the surface of the bracket and some in the micro gap.ConcIusion:The porous β-TCP scaffold have the connecticity and micro pore structure is evenly distributed upon the surface.Its mechanical properties can reach the strength of cancellous bone,which can provide better mechanical properties.The porous scaffold could promote cell adhesion,proliferation and angiogenesis to improve bone ingrowth.The 30 days cumulative drug release of ICA/PLGA sustained-release microspheres is up to 60%,with drug delivery capacity.The study on the preparation of ICA-beta tricalcium phosphate composite scaffold can be used for repair of rabbit femoral head necrosis.