Synthesis Of Selenium Doped Hydroxyapatite Via A Hydrothermal Procedure And The Experimental Study On Their Antitumor Effect

Hydroxyapatite,as the main inorganic component of hard tissue,can be chemically bonded to living tissue,and has good biocompatibility and bone conduction,so it is widely used in the field of bone tissue repair.Micro/nano multi-level structure is widely found in nature,providing a variety of biological special properties(lotus leaf surface self-cleaning,gecko reversible super-adhesive feet,moths not afraid of light,etc.).And micro/nano-structured surface of biological materials has the advantages of promoting integrin expression,cell adhesion,proliferation and differentiation.Human trace element selenium has antitumor,antibacterial,antiaging,improving human immunity and other functions.And the intake of selenium plays an important role on osteogenesis.Therefore,it has a very significant significance to prepare the new multi-functional biomaterial for bone repair with the good biocompatibility,osteoinduction,antitumor and antibacterial by combinating of HA,micro/nano-structure and selenium.In this paper,selenium doped hydroxyapatite(SeHA)with different micro/nanostructured surfaces was successfully prepared by hydrothermal method using urea as precipitant and sodium selenite(Na2SeO3)as selenium source and morphology modulator.At the same time,the effects of Na2SeO3 on the physical and chemical properties(crystal structure,chemical composition,morphology,ion release,etc.)of HA were studied.In addition,the protein adsorption performances,in vitro cell biocompatibility,osteogenesis induction and antitumor on SeHA powders with different micro/nanostructured were investigated and analyzed.The main contents and results are summarized as follows:Firstly,in the hydrothermal condition,using urea as a precipitating agent and different selenium doping rate(Se/(Se+P)mol%),SeHA powder were prepared which had a series gradient concentrations of Na2SeO3 at 150 ℃ for 3 h.Then,the effects of Na2SeO3 on the physicochemical properties and protein adsorption properties of HA were investigated by X-ray diffractometer(XRD),scanning electron microscopy(SEM),fourier Transform Infrared Spectrometer(FITR)and so on.The results showed that trace element selenium was present in HA with two forms of selenium(Se)and selenite(SeO32-).The crystallinity of HA decreased with the increase of doping rate,and when the doping rate reached 50%,vaterite appeared.The addition of Na2SeO3 could control the morphology of HA,transforming the surface of HA from whisker structure(blank control group)into radial particles(doping rate of 5%and below)and the layer particles(doping rate of 10%and 20%).The release of selenium-related ions from SeHA material increased with the increase of doping rate,and the cumulative release showed a typical slow release phenomenon,Which was beneficial to the sustained and long-term biological effect of selenium.The incorporation of selenium maked the SeHA to have a selective adsorption and controlled release on bovine serum albumin(BSA)and lysozyme(LSZ).Secondly,the in vitro cell biocompatibility and osteogenesis induction of SeHA was evaluated.The results showed that there had no cytotoxicity of SeHA material with doping rate of 5%and below in vitro.SeHA elution had no significant effect on the proliferation of osteoblasts(OB)and the osteogenic differentiation of rat bone marrow mesenchymal stem cells(BMSCs).The micro/nanostructured surface of SeHA had no significant effect on the proliferation of OB cells,but the micro/nanostructured surface of SeHA with 5%doping rate had a significant effect on the osteogenic differentiation of BMSCs.Finally,human osteogenic sarcoma cell line(SJSA-1)and hepatoma cell line(HepG2)were used as tumor cell model to explore the antitumor foundation of SeHA.The results showed that the growth inhibition and lethal effect of SeHA on tumor cells increased with the increase of doping rate.SeHA could induce the apoptosis of tumor cells through selenium-related ions.In summary,Na2SeO3 as the selenium source can be successfully incorporated into HA,and can effectively regulate HA growth to synthesize SeHA powder with different micro/nanostructures.SeHA with different micro/nanostructures has a selective protein adsorption and plays a key role in controlling protein release;Micro/nanostructures regulated by Na2SeO3 can effectively regulate cell differentiation behavior;In addition,the addition of trace element selenium give the SeHA material anti-tumor biological functions.The progress of this paper provides an important reference for the doping of trace elements and the construction of micro/nanostructures on hydroxyapatite,and opens up new ideas for the construction of new multifunctional bone tissue repair materials.