Preparation And Properties Of Self-curing Selenium-loaded Calcium Phosphate Bone Repair Material

Objective The selenium-containing bone grafting material has formed part of the main targets for the clinical application of artificial bone grafting materials due to its biological activities such as promoting bone repair,antitumor,and antibacterial.Currently reported selenium-containing bone repair materials,the selenium loading method is simple surface direct coating of Se element or ion exchange loading SeO₃^2-.Such selenium loading methods cannot have control over the release of selenium.While selenium acts on the biological safety of the human body,the quantity control is of great importance.This article is intended to apply the unique biochemical functions of selenium to the frontier problems of bone repair.Selenium is encapsulated with microspheres and compounded with self-curable calcium phosphate bone cement.The amount of encapsulated microspheres,microsphere diameter,micro The method of loading the drug with the ball,etc.In order to alleviate the"burst release effect"of the loaded selenium,control the release rate of the drug from the bone cement,and achieve controlled release.Methods Using the microsphere’s morphology,drug loading,encapsulation efficiency and slow-release properties in simulated body fluids as the main indicators,the quality of Na₂SeO₃-SA-CS microspheres was evaluated and analyzed,combined with atomic fluorescence spectrum,infrared analysis,thermogravimetric analysis and scanning electron microscopy were used to characterize the Na₂SeO₃-SA-CS microspheres.Na₂SeO₃-SA-CS microsphere-calcium phosphate bone cement composites were prepared,and the material quality was screened using curing time,anti-collapse,dependability,and slow-release selenium properties as main indicators.On this basis,anti-tumor activity of Na₂SeO₃-SA-CS microspheres-calcium phosphate bone cement composites was investigated to a certain extent using osteosarcoma MG63 cells as a cell model.Results（1）Na₂SeO₃-SA-CS microspheres were prepared by emulsion cross-linking method.A single factor experiment was conceived with glutaraldehyde dosage,curing temperature,sodium selenite,sodium alginate,chitosan and calcium chloride as variables to consider different variables.The effect of level on drug loading and encapsulation rate of Na₂SeO₃-SA-CS microspheres was designed.Orthogonal experiments were designed on the basis of definite factors.The SPSS23.0statistical software was utilized to perform Duncan multiple analysis and analysis of variance to determine the orthogonal test results.The best optimized process combination and validation.After optimization and verification,two optimized groups were obtained.The A₄B₁C₃D₄E₂ optimized microspheres had a suitable molding effect and almost no adhesion to each other.The encapsulation rate was 76.87%and the drug loading was 7.57%.It is 80%;the microspheres in the A₄B₁C₄D₄E₃ group have a higher degree of molding and better dispersibility.Their encapsulation efficiency and drug loading were 80.19%and 5.72%,respectively,and their final sustained released in vitro was 57.4%.（2）After theβ-phase bone cement was associated with Na₂SeO₃-SA-CS microspheres.The initial setting time and final setting time was shortened to 4.1min and 8.4min,which improved the thermal stability and anti-collapse ability of bone cement.Cumulative selenium release rate was 12.87%;the initial setting time and final setting time ofα-phase bone cement and Na₂SeO₃-SA-CS microspheres were reduced to 4.3min and 9.2min,which enhanced its thermal stability,anti-collapse ability and degradation ability.The cumulative selenium release rate after sustained-release in vitro for 1000h was 27.34%.（3）In vitroanti-tumorexperimentswithslow-releaseNa₂SeO₃-SA-CS microspheres-calcium phosphate bone cement composite sustained release solutions for 1d and 7d showed that CPC and pure CPC containing seleniumβ-TCP system could proliferate osteoma MG63 cells,adhesion and extracellular matrix mineralization inhibition were not obvious;CPC containing seleniumα-TCP system had a significant inhibitory effect on the proliferation,adhesion and extracellular matrix mineralization of sarcoma MG63 cells.Conclusion The combination of Na₂SeO₃-SA-CS microspheres and self-curable calcium phosphate bone cement shortens the curing time of bone cement,improved its dependability and anti-disintegration ability,effectively relieved the"burst release effect"of the loaded selenium and controlled the drug from the release rate of bone cement,it could achieve controlled and sustained release and inhibited the proliferation of sarcoma MG63 cells.