| WANG Jiaqi,BAI Yu,LI Ting,GAO Yuanming,MA Wen.Vitro Mineralization and Antibacterial Properties of Fluoro-selenium Double-doped Hydroxyapatite Coating[J],53(18):210-218 |
| Vitro Mineralization and Antibacterial Properties of Fluoro-selenium Double-doped Hydroxyapatite Coating |
| Received:October 12, 2023 Revised:December 29, 2023 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2024.18.019 |
| KeyWord:biological coating fluoro-seleno-hydroxyapatite mineralization property mineralization process antibacterial property suspension plasma spraying |
| Author | Institution |
| WANG Jiaqi |
Inner Mongolia Key Laboratory of Thin Film and Coating, School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot , China |
| BAI Yu |
Inner Mongolia Key Laboratory of Thin Film and Coating, School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot , China |
| LI Ting |
Inner Mongolia Key Laboratory of Thin Film and Coating, School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot , China |
| GAO Yuanming |
Inner Mongolia Key Laboratory of Thin Film and Coating, School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot , China |
| MA Wen |
Inner Mongolia Key Laboratory of Thin Film and Coating, School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot , China |
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| Abstract: |
| The work aims to prepare fluorine and selenium-doped hydroxyapatite nano-powder suspension by hydrothermal coprecipitation method and apply the co-doped hydroxyapatite coating on the surface of titanium substrate by suspension. By suspension plasma spraying technology, this short coating preparation process avoids drying, grinding powder and some other steps. Due to the weak antibacterial properties of hydroxyapatite, it is difficult to meet the requirements of medical applications. In this work, the effects of fluorine and selenium doping on the antibacterial activity and mineralization ability of the coating are studied. 0.7 mol/L aqueous solution was prepared by calcium nitrate tetrahydrate, diammonium hydrogen phosphate, ammonium fluoride and sodium selenite according to the stoichiometric ratio of hydroxyapatite. HA, Se-0.5FHA and Se-1.5FHA suspensions were prepared by coprecipitation method. The Se/P ratios of the three samples were 0, 15% and 15%, respectively. The F/ OH ratios were 0, 0.3 and 3, respectively. At 40 ℃, the solution of diammonium hydrogen phosphate, ammonium fluoride, sodium selenite was mixed and slowly added to calcium nitrate tetrahydrate. The titanium substrate (10 mm×10 mm× 2 mm) was sandblasted to increase the surface roughness, and then plasma sprayed with suspension by MC 60 spray gun (Medicoat AG, Switzerland). During the spraying process, the distance between the nozzle and the substrate surface was 40 mm, the transverse moving speed was 700 mm/s, and the longitudinal step length was 150 mm. After 20 layers of spraying, the coating thickness was maintained at about 80 um. The coatings were characterized by XRD, XPS and SEM-EDS. XRD analysis revealed that the coating was primarily composed of HA phase, with some products decomposing to form a small amount of α-TCP, β-TCP and TTCP during spraying. XPS analysis indicated that F- replaced OH- and SeO32– replaced PO43– into the lattice. The surface scan by EDS results showed that the coating contained Ca, P, Se, F and other elements, and Ca/ (Se + P) conformed to the stoichiometric ratio of hydroxyapatite, which was stable at about 1.67. The mineralization ability was evaluated by measuring the weight gain and pH change of the coating before and after immersion in simulated body fluid (SBF). Because the incorporation of Se element into HA might increase lattice expansion and solubility, the crystals tended to stabilize with the increase of F content, and the formation rate of HA mineralized layer accelerated. After 5 d of mineralization, the weight gain of Se-1.5FHA coating was up to 0.013 g/cm2, and the EDS spectra showed that Ca/(Se + P) after mineralization was higher than 1.67, indicating that Ca2+ and PO43– were absorbed on the surface of the coating, and an apatite layer with Ca/P greater than 1.67 was formed. Bacterial culture experiments using staphylococcus aureus suspension showed that the absorbance of the coating with F and Se elements was much lower than that of the HA group and was consistent with the law of colony growth. Doping F and Se elements can improve the mineralization effect of HA coating and avoid the dissolution of HA caused by single Se. Compared with the HA coating, the number of bacteria in the doped samples decreases by about two orders of magnitude, providing an implant material with good bacteriostatic and mineralization ability for bone defects. |
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