相转移溶菌酶用于氧化锆全瓷种植材料表面改性后介导羟基磷灰石涂层的生物活性

Bioactivity of phase-transition lysozyme for surface modification of zirconia all-ceramic implant material mediating hydroxyapatite coating

背景:氧化锆种植体因良好的生物相容性被用于口腔种植领域,因其具有生物惰性,所以需对种植体表面进行改性来提高生物活性,羟基磷灰石涂层是广泛应用于种植体表面的改性技术。目的:利用相转变溶菌酶在氧化锆表面构建羟基磷灰石涂层,赋予其生物活性,提高种植体成功率。方法:将相转变溶菌酶溶液滴至光滑的氧化锆试件表面,反应2 h;将相转变溶菌酶改性氧化锆试件置于模拟体液中孵育10 d,诱导羟基磷灰石涂层。检测未改性氧化锆试件、相转变溶菌酶改性氧化锆试件与羟基磷灰石涂层氧化锆试件的接触角、粗糙度与机械性能;将3种氧化锆试件分别与MC3T3-E1细胞共培养,检测细胞增殖与碱性磷酸酶活性;将未改性氧化锆试件、羟基磷灰石涂层氧化锆试件分别与MC3T3-E1细胞共培养,扫描电镜下观察细胞黏附。结果与结论:①羟基磷灰石涂层组试件的接触角小于未改性组(P<0.05),粗糙度大于未改性组(P<0.05);3组试件的维氏硬度和断裂强度比较差异无显著性意义(P>0.05);②CCK-8检测显示,羟基磷灰石涂层组培养3,5,7 d的细胞增殖吸光度值均大于相转变溶菌酶组、未改性处理组(P<0.05);羟基磷灰石涂层组培养7,14 d的细胞碱性磷酸酶活性均高于相转变溶菌酶组、未改性处理组(P<0.05);③扫描电镜下可见,培养12 h,MC3T3-E1细胞紧密贴附于两种氧化锆材料表面;培养3 d后,两种材料表面的细胞数量增加,其中羟基磷灰石涂层组的细胞数量更多并出现细胞连接;④结果表明,对于氧化锆全瓷材料,在相转变溶菌酶改性的基础上制备羟基磷灰石涂层,可提高其亲水性、细胞相容性,且不影响材料的机械性能。

BACKGROUND:Zirconium implants are used in the field of oral implants due to good biocompatibility.Because of its biological inertness,the surface of the implant needs to be modified to improve its bioactivity.Hydroxyapatite coating is a widely used modification technique for implant surfaces.OBJECTIVE:The phase-transition lysozyme was modified on the zirconia surface,based on which a hydroxyapatite coating was constructed to confer its bioactivity and improve the success rate of implants.METHODS:The phase-transition lysozyme solution was dropped onto the surface of the smooth zirconia specimen for 2 hours.The phase-transition lysozymemodified zirconia specimen was incubated in the simulated body fluid for 10 days to induce the hydroxyapatite coating.The contact angle,roughness and mechanical properties of unmodified zirconia specimens,phase-transition lysozyme-modified zirconia specimens and hydroxyapatite-coated zirconia specimens were tested.The three kinds of zirconia specimens were co-cultured with MC3T3-E1 cells,separately.The cell proliferation and alkaline phosphatase activity were detected.Unmodified zirconia specimens and hydroxyapatite-coated zirconia specimens were co-cultured with MC3T3-E1 cells,separately,and cell adhesion was observed under a scanning electron microscope.RESULTS AND CONCLUSION:(1)The contact angle of the hydroxyapatite coating group was smaller than that of the unmodified group(P<0.05),and the roughness was greater than that of the unmodified group(P<0.05).There was no significant difference in the Vickers hardness and fracture strength of the three groups of specimens(P>0.05).(2)CCK-8 assay showed that the absorbance values of cell proliferation in the hydroxyapatite coating group on 3,5,and 7 days of culture were higher than those in the phase-transition lysozyme group and the unmodified group(P<0.05).The alkaline phosphatase activity of the hydroxyapatite coating group was higher than that of the phase-transition lysozyme group and the unmodified group at 7 and 14 days of culture(P<0.05).(3)Scanning electron microscope showed that MC3T3-E1 cells adhered closely to the surfaces of the two kinds of zirconia materials after 12 hours of culture.After 3 days of culture,the number of cells on the surfaces of the two materials increased,and the number of cells in the hydroxyapatite coating group was high and cell junctions appeared.(4)The results show that for zirconia all-ceramic materials,the preparation of hydroxyapatite coating on the basis of phase-transition lysozyme modification can improve its hydrophilicity and cytocompatibility without affecting the mechanical properties of the material.