Rubidium-modified bioactive glass-ceramics with hydroxyapatite crystals for bone regeneration

In order to study the influence of rubidium(Rb)addition on the phase composition,microstructure,mechanical properties and cell response of bioactive glass-ceramics,CaO−SiO2−Na2O−B2O3−MgO−ZnO−P2O5 glass system was designed with and without addition of Rb.The results show that hydroxyapatite(HA)and Mg−whitelockite(Ca18Mg2H2(PO4)14)crystalline phases are formed in the glass matrix without Rb.After the addition of Rb,only HA phase is detected.The grain size of the crystals in the glass-ceramics is larger with the addition of Rb than that of samples without Rb.Rb addition can improve the bending strength of glass-ceramics.The cultivation of human bone marrow mesenchymal stem cells(hBMSCs)on Rb-containing glass-ceramics demonstrates enhanced cell adhesion,proliferation and ALP activity.In conclusion,Rb-modified glass-ceramics exhibit good mechanical property,excellent bioactivity and biocompatibility,which have potential for bone regeneration application.

RESEARCH ON A NEW TYPE OF MACHINABLE BIOACTIVE GLASS-CERAMICS

A new type of machinable bioactive glass-ceramics for bone substitution has been developed in the glass system SiO_2-MgO-K_2O-F^--CaO-P_2O_5, which contains Mg- muscovite [K_2Mg_5 (Si_8O_(20)) F_4] and fluorapatite as the two main crystal phases. The phase separation and the crystallization of the glass have been studied. A series of tests have showed that the material is good at mechanical property and bioactivity. Espe- cially, by analysing the structure of the interface layer between the material and the bone of animal with scanning electron microscope, electron probe, etc., it has been found that the new bone hydroxya- patite is formed on the surface of the material so that the material is connected firmly with the bone.

Preparation of Machinable Bioactive Glass-ceramics by Sol-gel Method

The purpose of this research was to prepare machinable bioactive glass-ceramics by sol-gel method. A multi-component composite sol with great uniformity and stability was first prepared by a 2-step method. The composite sol was then transformed into gel by aging under different temperatures. The gel was dried finally by super critically drying method and sintered to obtain the machinable bioactive glass-ceramics. Effect of thermal treatment on crystallization of the glass-ceramics was investigated by X-ray diffraction （ XRD ） analysis. Microstructure of the glass- ceramics was observed by Scanning Electron Microscopy （SEM） and the mechanism of machinability was discussed. Phlogopite and hydroxylapatite were identified as main crystal phases by XRD analysis under thermal treatment at 750℃ and 950℃ for 1.5 h separately. The relative bulk density could achieve 99% under 1050℃ for 4 h. Microstructure of the glass-ceramics showed that the randomly distributed phlogopite and hydroxylapatite phases were favorable to the machinability of the glass-ceramics. A mean bending strength of about 160- 180 MPa and a fracture toughness parameter KIC of aboat 2.1-2.3 were determined for the glass-ceramics.

Fabrication and multiscale characterization of 3D silver containing bioactive glass-ceramic scaffolds

In this work,we fabricated and characterized bioactive 3D glass-ceramic scaffolds with inherent antibacterial properties.The sol-gel(solution-gelation)technique and the sacrificial template method were applied for the fabrication of 3D highly porous scaffolds in the 58.6SiO2-24.9CaO-7.2P2O5-4.2Al2O3–1.5Na2O−1.5K2O–2.1Ag2O system(Ag-BG).This system is known for its advanced bioactive and antibacterial properties.The fabrication of 3D scaffolds has potential applications that impact tissue engineering.The study of the developed scaffolds from macro-characteristics to nano-,revealed a strong correlation between the macroscale properties such as antibacterial action,bioactivity with the microstructural characteristics such as elemental analysis,crystallinity.Elemental homogeneity,morphological,and microstructural characteristics of the scaffolds were studied by scanning electron microscopy associated with energy dispersive spectroscopy(SEM-EDS),transmittance electron microscopy(TEM),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),Fourier transform infrared spectroscopy(FTIR),and UV-visible spectroscopy methods.The compressive strength of the 3D scaffolds was measured within the range of values for glass-ceramic scaffolds with similar compositions,porosity,and pore size.The capability of the scaffolds to form an apatite-like phase was tested by immersing the scaffolds in simulated body fluid(SBF)and the antibacterial response against methicillin-resistant Staphylococcus aureus(MRSA)was studied.The formation of an apatite phase was observed after two weeks of immersion in SBF and the anti-MRSA effect occurs after both direct and indirect exposure.

Fe_2O_3-CaO-SiO_2体系铁磁微晶玻璃的磁性及生物活性

制备了添加少量B2O3和P2O5后的Fe2O3 CaO SiO2体系铁磁微晶玻璃,并进行了微观结构分析、XRD分析、磁性检测以及生理模拟液的浸泡实验.实验结果表明,制备的微晶玻璃材料同时具备磁性和生物活性这两种重要性能.不经过核化处理在1000℃晶化2h后能够获得较理想的磁铁矿主晶相和硅灰石次晶相均匀致密分布的微观组织,所得微晶玻璃具有最佳的磁性能.铁含量提高能够增加微晶玻璃的磁性,然而会抑制微晶玻璃表面羟基磷灰石的形成,从而降低其生物活性.

钙铁硅铁磁体微晶玻璃的细胞学及动物学实验研究

采用细胞学实验和动物实验方法对用于温热治疗肿瘤的钙铁硅铁磁体微晶玻璃进行生物活性研究。动物试验结果表明,试样对动物无明显毒性,对动物的生长也无任何不利影响。细胞学实验结果表明,试样的细胞生物活性良好。

钙铁硅铁磁体微晶玻璃生物活性的模拟体液研究

为了研究用作温热治疗肿瘤热种子材料的钙铁硅铁磁体微晶玻璃的生物活性 ,试样在模拟体液中浸泡以后 ,用SEM、俄歇电子能谱、FT -IR对其表面生成的薄膜进行观察和分析。研究结果表明 ,试样表面的硅胶层上生成了能与人体组织良好结合的碳酸羟基磷灰石 。

铁磁性微晶玻璃的制备

采用熔融法制备了SiO_2-Na_2O-CaO-P_2O_5-Fe_2O_3系微晶玻璃。制备过程中磁铁矿晶相在玻璃自然冷却时自然析出,故不需要对玻璃进行核化和晶化等热处理。利用XRD确定了样品晶相组成并计算了样品中晶体的晶格常数和晶粒度,采用振动样品磁强计(VSM)测试了样品的磁性能。结果表明:所制微晶玻璃只含有磁铁矿晶相并具有生物活性;Fe_2O_3质量分数为45%的样品性能最佳,其比饱和磁矩为20.24A·m^2/kg,内禀矫顽力H_(cj)为7kA/m。

铁磁性微晶玻璃热种子材料的研制

采用基础玻璃熔融析晶法制备铁磁性微晶玻璃热种子材料,其中基础玻璃的组成以Fe2O3-CaO-SiO2为主体并添加少量B2O3和P2O5。借DTA,XRD分析确定了合理的热处理制度,制备了以Fe3O4为主晶相的微晶玻璃,并对其磁性能及生物活性进行了试验。结果表明:所得的微晶玻璃材料单位质量的磁化强度达到22.6A·m–1·g–1,且能生成羟基磷灰石,故材料具有生物活性。