| Bone scaffold materials have good biocompatibility,biodegradability,bone conductivity and certain bone induction.It has been used in clinic to repair human bone tissue defects,replace dysfunctional or failing tissues,and even replace some or all of the diseased organs.In recent years,great progress has been made in this field.This is not only the urgent demand of human beings for health and longevity,but also the driving force of our research.Calcium sulfate artificial bone material and calcium phosphate artificial bone material are the most widely used bioceramic materials for bone repair.Therefore,on the basis of studying and analyzing the existing materials,The representative?-calcium sulfate half-hydrate and calcium hydrogen phosphate dihydrate?Brushite?,were selected to obtain a kind of scaffold material with good degradability,biocoMPatibility,bone conduction and bone induction.Considering the difference of degradation between the two materials,this paper intends to adopt the design of core-shell structure to achieve step degradation,use degraded calcium ion to guide the design of bone induction,and construct the scaffold material.In this paper,?-monohydrate calcium sulfate powder and calcium hydrogen phosphate powder were prepared,and calcium hydrogen phosphate spherical particles were prepared with the help of silica gel.The calcium sulfate powder was coated on the outer surface of calcium hydrogen phosphate spherical particles with the aid of aqueous solution,and the core-shell composite spherical particle material with calcium hydrogen phosphate dihydrate as core and calcium sulfur dihydrate as shell was prepared.The composite spherical particle material has more outstanding advantages in biological activity and biodegradability than single calcium sulfate material and single calcium hydrogen phosphate material,and has a wider application prospect in the future.In order to further improve the properties of calcium hydrogen phosphate dihydrate/calcium sulfate dihydrate core-shell composite spherical particles,gelatin and core-shell composite spherical particles were reasonably constructed in the self-made mould.Finally,the gelatin/calcium hydrogen phosphate dihydrate/calcium sulfate dihydrate composite porous biological scaffold was obtained,and the composition,structure and properties of the scaffold were discussed.This paper mainly explores the following work:?1?Using cetyltrimethyl ammonium bromide(C19H42BrN),calcium chloride dihydrate(CaCl2·2H2O)and sodium dihydrogen phosphate?NaH2PO4·2H2O?as raw materials,calcium hydrogen phosphate dihydrate powder?CaHPO4·2H2O,Brushite?was prepared by precipitation method and ultrasonic concussion.Finally,the layered calcium hydrogen phosphate powder with lamellar structure was obtained.The length of the prepared calcium hydrogen phosphate nanoparticles is about 3-5?m and the width is about 150 nm.The results of cytotoxicity test showed that the powder had no cytotoxicity.The?-monohydrate calcium sulfate powder was made in the laboratory,and its structure was identified and analyzed.?2?The composite spherical particles with core-shell structure of calcium hydrogen phosphate dihydrate/calcium sulfate dihydrate were prepared by rolling.The size of the spherical particles was 1.0 to 2.0 mm.The particle size of the spherical particles was 1.0to 2.0 mm.Through the in vitro biodegradation experiment,it was found that after soaking the composite spherical particles of calcium hydrogen phosphate dihydrate/calcium sulfate dihydrate core-shell structure in human simulated body fluid,the degradation was basically completed in 45 days.The cytotoxicity of core-shell spherical particles was tested.The results showed that calcium hydrogen phosphate dihydrate/calcium sulfate dihydrate core-shell structure composite spherical particles had no cytotoxicity.?3?Using gelatin as adhesive,cross-linking agent and degradation regulator,Porous calcium hydrogen phosphate dihydrate/calcium sulfate dihydrate/gelatin porous scaffolds were prepared by stacking and aggregating porous calcium hydrogen phosphate dihydrate/calcium sulfate dihydrate core-shell composite spherical particles in a self-made mold.The results showed that the porosity of the composite scaffold was about 60%,and the average compressive strength of gelatin/calcium hydrogen phosphate dihydrate/calcium sulfate dihydrate porous scaffold was 6.1 MPa;.Apatite deposition appeared in the process of gelatin/calcium hydrogen phosphate dihydrate/calcium sulfate dihydrate porous scaffold immersed in human simulated body fluid,indicating that the scaffold has good biological activity.During the 80-day cycle of this experiment,gelatin/calcium hydrogen phosphate dihydrate/calcium sulfate dihydrate porous scaffolds were still not completely degraded.The results of cytotoxicity test showed that the cytotoxicity of gelatin/calcium hydrogen phosphate dihydrate/calcium sulfate dihydrate porous scaffold was grade 0 or grade 1,indicating that the scaffold material had no cytotoxicity.The materials prepared in this study meet the basic requirements of bone scaffold materials.It is necessary to further study their biological properties and biomedical performance in vivo through further animal experiments. |
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