β-TCP/α-CSH复合植骨材料的制备与理化性能检测

目的探讨近单相β-磷酸三钙(β-TCP)颗粒与α-半水硫酸钙(α-CSH)制备复合植骨材料的可行性和方法。方法松质骨通过2次煅烧和磷酸氢二胺[(NH4)2HPO4]溶液处理制备近单相β-TCP颗粒;二水硫酸钙在额定温度和压力下,采用水热方法制备α-CSH。将近单相β-TCP颗粒与α-CSH混合制备β-TCP/α-CSH复合植骨材料。进行差热-热重(DTA)、X射线衍射(XRD)、骨扫描电子显微镜、孔隙率和固化强度检测。结果采用两步煅烧法可成功制备近单相β-TCP颗粒,其孔隙率为57.63%,表现为大孔/微孔的双峰曲线;额定温度和压力可制备高纯度α-CSH。将β-TCP颗粒和α-CSH混合获得复合植骨材料,其固化后平均抗压强度在1 d时达到7.86 MPa,较β-TCP抗压强度升高约1倍。结论采用上述方法成功制备具有自固化性能的β-TCP/α-CSH新型复合植骨材料。     

SrHA/PMMA复合骨水泥的制备、理化性能及细胞相容性研究

目的结合PMMA和锶羟基磷灰石(Sr HA)各自的优势,制备出兼具高的力学强度、合适的固化时间、较低的热释放、生物活性和骨整合性能的Sr HA/PMMA复合骨水泥,并系统性地研究Sr HA的引入对复合骨水泥的体外固化性能、力学强度和生物学性能的影响。方法将水热合成法制备的锶羟基磷灰石引入PMMA基体,制备Sr HA/PMMA复合骨水泥。系统性地对Sr HA/PMMA复合骨水泥的力学强度、固化时间、热释放、生物活性进行研究。将复合骨水泥和细胞共培养,利用MTT法、扫描电镜等研究Sr HA/PMMA复合骨水泥的细胞毒性,粘附和增殖。结果结果表明,与纯的PMMA骨水泥(对照组)相比,Sr HA/PMMA复合骨水泥的固化热释放明显降低(约80~84℃),同时又维持了合适的固化时间(8~11分钟)和较好的力学性能(抗压强度为90MPa左右)。Sr HA的引入,不仅赋予了复合骨水泥生物活性,也显著地改善了其细胞/材料的相互作用。浸泡在SBF后,Sr HA/PMMA复合骨水泥显示出更好的体外矿化性能。与成骨细胞MC3T3-E1共培养后,表面沉积的羟基磷灰石能够更好的促进细胞的粘附和爬行。结论兼具优异的理化性能和生物活性的Sr HA/PMMA复合骨水泥,有着广阔的骨科微创修复应用前景。     

射频磁控溅射法制备羟基磷灰石/β-磷酸三钙生物涂层

目的以粉末冶金烧成的羟基磷灰石(HA)/-β磷酸三钙(β-TCP)陶瓷为靶材,采用磁控溅射法在钛合金(Ti6Al4V)基体上制备HA/β-TCP生物涂层。方法利用XRD研究了复合涂层的晶化程度,讨论了涂层成分与生物降解性及相容性的关系。结果HA/β-TCP生物涂层为非晶态,经700℃,3h大气处理可显著提高涂层的晶化程度,当涂层成分为50wt%HA/50wt%β-TCP时其细胞相容性最好。结论在钛合金基体上制备HA/β-TCP生物涂层,通过HA与β-TCP的复合来控制材料的降解速度,使它的降解速度与周围骨组织的生长速度相匹配,使植入体具有良好的生物降解性、生物活性和力学性能。     

更正启事

由于我刊工作失误将29卷第3期P493(文章题目:《α-磷酸三钙/HA晶须/羧甲基壳聚糖-明胶复合增强多孔骨水泥的制备研究》;作者:卫冬娟等)中的图2、3位置颠倒。由此给作者和读者带来不便,谨请凉解。现更正如下:     

β-TCP/α-CSH复合植骨材料固化性能与力学强度

目的检测β-磷酸三钙(β-TCP)/α-半水硫酸钙(α-CSH)复合人工骨的固化性能与力学强度。方法将β-TCP/α-CSH复合人工骨与蒸馏水按1g:0.1 mL、1g:0.2 mL、1g:0.3 mL、1g:0.4 mL、1g:0.5 mL的比例混合,测试其初凝时间、终凝时间、压缩强度,并进行X线衍射和扫描电镜观察。结果复合人工骨的固化时间均随着固化液比例的增加,初凝时间和终凝时间逐渐延长,固液比为1g:0.2 mL时初凝时间为(4.6±1.3)min,终凝时间为(13.1±2.9)min。复合人工骨的平均抗压强度固化1 d时达到7.86 MPa,较近单相β-TCP组升高约1倍,XRD检测固化后没有其他物质产生,只是α-CSH在固化过程中转化为二水硫酸钙(CSD),扫描电镜可见固化后粗大CSD颗粒形成短柱状结构覆盖在多孔状β-TCP表面。结论通过调整β-TCP/α-CSH的固液比可以调整其固化时间和压缩强度。     

碳纤维增强α-磷酸三钙骨水泥的研究

为提高α-磷酸三钙（α—TCP）骨水泥的强度及降低其脆性，将表面改性后的碳纤维（CF）与α—TCP粉复合，制备成α—TCP／CF复合增强骨水泥。通过Ringer’s体液浸泡观察骨水泥快速结晶自固化能力，运用扫描电子显微镜（SEM）及抗压强度测试仪对复合材料浸泡后试样进行断面显微结构分析及抗压强度测试。结果显示，α—TCP骨水泥块浸泡5d后即转化生成片状羟基磷灰石晶体；适量的碳纤维在骨水泥基体中分布均匀，与基体结合性好，可得到抗压强度增强的骨修复材料；当碳纤维的加入重量百分数为0．5％时，复合材料抗压强度达到46．7MPa，比未增强的α—TCP材料提高了22％。     

纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥的性能

背景：目前普遍使用的黏合剂对粉碎骨折块进行黏合复位或多或少都存在一些缺陷。 目的：研制具有黏接骨骼作用的生物活性骨水泥。 方法：应用共沉淀法制备纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合材料作为骨水泥的固相粉体,将柠檬酸衍生物配制成溶液作为液相。通过优化实验,从骨水泥的固化时间、抗压强度、抗拉强度、抗稀散性等方面确定最佳配比。 结果与结论：纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠质量比为65/35,其中羧甲基壳聚糖和海藻酸钠质量比为4∶1时复合成粉体,并按固液比为1.0∶0.5(g∶mL)调拌后形成的骨水泥呈膏状,塑形性和抗稀散性能良好,固化时间12~18 min,抗压强度为(4.5±2.1) MPa。体外黏接猪股骨头抗拉强度在不同室温下无显著性差异无显著性意义(P > 0.05),固化后2 h的抗拉强度达到24 h的94%。骨水泥为多孔状结构,孔径为100~300 μm,纳米羟基磷灰石分布较均匀。提示制备的纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥具有良好的生物活性、适当的力学强度以及较好的黏合强度。     

钙磷生物陶瓷多孔骨修复材料的制备*

以适量的Mg(H2PO4)2-(NaPO3)6为粘结剂,HA和-TCP粉末为原料,用有机泡沫浸渍法制备钙磷多孔生物陶瓷坯体,并在850℃烧成,探索在较低烧结温度下制备钙磷多孔生物陶瓷的工艺。采用X射线衍射(XRD)、扫描电镜(SEM)、能谱(EDS)等方法对多孔生物陶瓷的物相组成、显微结构、物理性能进行了分析。烧成后的钙磷生物陶瓷多孔支架主要由-TCP、-Ca2P2O7和CaO-MgO-Na2O-P2O5磷酸盐玻璃组成。烧结过程中,HA发生了向-TCP的转化,部分-TCP转化为-Ca2P2O7。多孔支架具有良好三维连通性的孔隙结构,孔径为200～500m,孔隙率达81%,抗压强度为1.1～1.5MPa。     

聚DL-乳酸/羟基磷灰石复合材料修复长骨缺损的实验研究

目的 :评价羟基磷灰石 (HA)复合聚DL 乳酸 (PDLLA )制备的材料体内成骨能力。方法 :将PDLLA和PDLLA/HA( 2 0wt % )材料采用盐结晶颗粒沥滤法制成三维多孔材料 ,45例 1cm兔桡骨去骨膜缺损分为三组 ,分别植入 2种材料和作空白对照 ,术后 2 ,4,8,12周行X线、组织学及扫描电镜观察骨生成状况 ,8、12周行生物力学测试 (三点折弯强度 )。结果 :泡沫状PDLLA/HA ( 2 0wt % )材料比纯PDLLA成骨更好 (P <0 .0 5 ) ,实验组与对照组相比差异有显著性 (P <0 .0 5 )。结论 :PDLLA具有良好的生物相容性 ,制成多孔状具有较好的骨传导性能 ,HA( 2 0wt % )的加入促进了多孔PDLLA的骨传导能力 ,提高了骨生成的质量。PDLLA/HA( 2 0wt % )复合材料是一种有临床应用前景的骨移植材料。     

胶原对TTCP/MCPM骨水泥性能的影响

以混合后钙磷比为1.67的磷酸四钙(TTCP)和一水磷酸二氢钙(MCPM)粉体为原料,按固液比3∶1分别用水和5.24 mg/ml自制Ⅰ型胶原溶胶作固化液制备骨水泥试样,测定其凝结时间和抗压强度。结果显示,用胶原作固化液可使TTCP/MCPM骨水泥的抗压强度由17.8±1.9 MPa增至22.7±1.6 MPa,对凝结时间则没有明显影响;两种试样经模拟体液(SBF)浸泡抗压强度均有增加,尤以胶原溶胶固化的试样增幅较大,SBF浸泡4 d和14 d,抗压强度分别增至31.8±3.9 MPa(胶原溶胶)/19.5±1.3 MPa(水)和38.1±3.1 MPa/21.9±2.2 MPa。对比胶原矿化前后的红外谱图发现,矿化后胶原的酰胺Ⅰ带特征峰红移,酰胺Ⅱ带、Ⅲ带几乎消失,提示在胶原与羟基磷灰石(HA)之间发生了明显的化学作用,这应是胶原对TTCP/MCPM骨水泥增强作用的基础;而SBF浸泡前后试样表面的SEM和XRD图谱则显示,SBF浸泡在使透钙磷石(DCPD)转化为HA的同时,又沉积生成了大量新的HA,使试样表面更加致密、光滑,这既是SBF浸泡增强的机理,也揭示TTCP/MCPM骨水泥的凝结硬化是先生成DCPD...     

Preparation and compressive strength of alpha-tricalcium phosphate/gelatin gel composite cement.

A novel alpha-tricalcium phosphate (TCP) and gelatin gel composite cement was prepared, and the effects of gelatin content, liquid/powder ratio, setting time, and additives (rod-like hydroxyapatite and CaTiO3 particles) on the microstructure and compressive strength of the setting product were investigated. Addition of gelatin gel to alpha-TCP cement resulted in the formation of a porous solid possessing pores of 20-100 microm in diameter whose pore diameter increased with increasing gelatin gel content. The compressive strength of alpha-TCP cement after 1 week increased from 9.0 to 14.1 MPa with increasing gelatin gel content up to 5 wt % and thereafter decreased. The compressive strength of the cement containing 5 wt % gelatin gel increased with time up to 35 MPa after 1 month whereas without gelatin gel it was approximately 20 MPa. Dispersion of 5 wt % of rod-like hydroxyapatite and CaTiO3 powders with alpha-TCP cement containing 5 wt % gelatin gel increased the compressive strength after 1 week from 14.1 to 31.3 and 34.8 MPa, respectively.     

Modulation of porosity in apatitic cements by the use of alpha-tricalcium phosphate-calcium sulphate dihydrate mixtures

Calcium phosphate bone cements are injectable biomaterials that are being used in dental and orthopaedic applications through minimally invasive surgery techniques. Nowadays, apatitic bone cements based on alpha-tricalcium phosphate (alpha-TCP) are of special interest due to their self-setting behaviour when mixed with an aqueous liquid phase. In this study, a new method to improve osteointegration of alpha-TCP-based cements is presented. This method consists in the modification of the cement's powder phase with different amounts of calcium sulphate dihydrate (CSD). The resulting hardening properties of the new biphasic cements are a combination between the progressive hardening due to the main alpha-TCP reactant and the progressive dissolution of the CSD phase, which render a porous material. It was observed that the maximum compressive strength of Biocement-H (45 MPa) decreased as the amount of CSD increased in the cement powder mixture ( approximately 30 MPa for 25 wt% of CSD). It was also observed that after complete dissolution of the CSD phase a porous apatitic structure appears with a mechanical compressive strength suitable for cancellous bone applications (10 MPa).     

Biphasic calcium phosphate nanocomposite porous scaffolds for load-bearing bone tissue engineering

A novel biodegradable nanocomposite porous scaffold comprising a beta-tricalcium phosphate (beta-TCP) matrix and hydroxyl apatite (HA) nanofibers was developed and studied for load-bearing bone tissue engineering. HA nanofibers were prepared with a biomimetic precipitation method. The composite scaffolds were fabricated by a method combining the gel casting and polymer sponge techniques. The role of HA nanofibers in enhancing the mechanical properties of the scaffold was investigated. Compression tests were performed to measure the compressive strength, modulus and toughness of the porous scaffolds. The identification and morphology of HA nanofibers were determined by X-ray diffraction and transmission electron microscopy, respectively. Scanning electron microscopy was used to examine the morphology of porous scaffolds and fracture surfaces to reveal the dominant toughening mechanisms. The results showed that the mechanical property of the scaffold was significantly enhanced by the inclusion of HA nanofibers. The porous composite scaffold attained a compressive strength of 9.8 +/- 0.3 MPa, comparable to the high-end value (2-10 MPa) of cancellous bone. The toughness of the scaffold increased from 1.00+/-0.04 to 1.72+/-0.02 kN/m, as the concentration of HA nanofibers increased from 0 to 5 wt %.     

Comparative study of bone cements prepared with either HA or alpha-TCP and functionalized methacrylates

The properties of bone cements prepared with both hydroxyapatite (HA) and alpha-tricalcium phosphate (alpha-TCP) and methacrylates containing acidic or basic groups are the main interest of this article. The presence of methacrylic acid or diethyl amino ethyl methacrylate as comonomers in the bone cement and both ceramic types as filler were found not to affect the amount of residual monomer, which was generally less than 4.5 wt%. In contrast, setting times, maximum temperature, and glass transition temperature were found to be composition dependent. For samples with acidic comonomer, a faster setting time, a higher maximum temperature, and higher glass transition temperatures were observed compared to those with the basic comonomer. The presence of the fillers slightly increased the setting time but did not affect the other parameters. The mechanical properties of the filled bone cements depended mainly on composition and type of testing. Both HA or alpha-TCP filled systems fulfilled the minimum compressive strength required for bone cement application, although a significantly lower value was observed for the alkaline comonomer systems. The minimum bending strength was not satisfied by any of these formulations. The tensile and shear strength of these composites ranged from 20 to 37.9 and from 18 to 27 MPa, respectively. In all cases it was higher for bone cements containing methacrylic acid. The results of this study suggest that the properties of dry unfilled bone cements prepared with MAA are comparable to CMW 3 in mechanical terms but inferior in their setting properties.     

Mechanical and biological properties of hydroxyapatite/tricalcium phosphate scaffolds coated with poly(lactic-co-glycolic acid)

Regeneration of bone, cartilage and osteochondral tissues by tissue engineering has attracted intense attention due to its potential advantages over the traditional replacement of tissues with synthetic implants. Nevertheless, there is still a dearth of ideal or suitable scaffolds based on porous biomaterials, and the present study was undertaken to develop and evaluate a useful porous composite scaffold system. Here, hydroxyapatite (HA)/tricalcium phosphate (TCP) scaffolds (average pore size: 500 μm; porosity: 87%) were prepared by a polyurethane foam replica method, followed by modification with infiltration and coating of poly(lactic-co-glycolic acid) (PLGA). The thermal shock resistance of the composite scaffolds was evaluated by measuring the compressive strength before and after quenching or freezing treatment. The porous structure (in terms of pore size, porosity and pore interconnectivity) of the composite scaffolds was examined. The penetration of the bone marrow stromal stem cells into the scaffolds and the attachment of the cells onto the scaffolds were also investigated. It was shown that the PLGA incorporation in the HA/TCP scaffolds significantly increased the compressive strength up to 660 kPa and the residual compressive strength after the freezing treatment decreased to 160 kPa, which was, however, sufficient for the scaffolds to withstand subsequent cell culture procedures and a freeze–drying process. On the other hand, the PLGA coating on the strut surfaces of the scaffolds was rather thin (<5 μm) and apparently porous, maintaining the high open porosity of the HA/TCP scaffolds, resulting in desirable migration and attachment of the bone marrow stromal stem cells, although a thicker PLGA coating would have imparted a higher compressive strength of the PLGA-coated porous HA/TCP composite scaffolds.     

硅酸钙-磷酸盐复合骨水泥的制备及其性能研究

分别以α-磷酸三钙（α—TCP）、磷酸四钙（TTCP）为基本原料，添加羟基磷灰石（HAP）、磷酸氢钙（DCPD）、碳酸钙（CaCO2）、氧化钙（CaO）等其它辅料，并与一定量的无定形硅酸钙（CaSiO3）进行复合，确定了钙磷比均为1．50的六种骨水泥配方，对其基本性能进行了研究。对固化骨水泥样品进行了Ringer’S模拟液浸泡实验，研究了浸泡液pH值、样品的抗压强度随浸泡时间的变化。结果表明：调和液0．25MK2HPO4／KH2PO4和无定形CaSiO3对骨水泥有促凝作用，缩短骨水泥的终凝时间，其中初凝时间为4～5．5min，终凝时间为18～19．5min；同时添加适量无定形CaSiO3可以显著提高骨水泥的抗压强度，其中添加适量无定形CaSiO3的以α—TCP为主要原料的骨水泥Ringer’s模拟液浸泡两周后抗压强度可达45．3MPa。     

Characterization of a novel calcium phosphate/sulphate bone cement

Apatitic cements have shown excellent biocompatibility and adequate mechanical properties but have slow resorption in the human body. To assure that new bone tissue grows into the bone defect, a certain porosity is necessary although hard to achieve in injectable cements with suitable mechanical properties. An attempt was made by mixing alpha-tricalcium phosphate (alpha-TCP), calcium sulphate hemihydrate (CSH) and an aqueous solution containing 2.5 wt% of Na(2)HPO(4). The aim was to obtain a material containing two phases: a) one apatitic phase (calcium-deficient hydroxyapatite; CDHA) and b) one resorbable phase (calcium sulphate dihydrate; CSD). alpha-TCP and CSH mixtures were produced at relative intervals of 20 wt%. The liquid-to-powder (L/P) ratio to obtain a paste was 0.32 mLg(-1). The highest compressive strength (34 MPa) was obtained for the pure alpha-TCP sample. The strength was, in a first approximation, directly correlated to the weight proportions of the powders. X-ray diffraction analysis showed that the relative intensity for CDHA increased linearly, and the one for CSD decreased exponentially, when the amount of alpha-TCP increased. Thus, CSH ceased to transform to CSD when the amount of alpha-TCP increased. Observations in environmental scanning electron microscopy confirmed the X-ray diffraction results. CSH-crystals (100 microm) were embedded in the HA-matrix permitting gradual porosity in the material when resorbed.     

Composites made of rapidly resorbable ceramics and poly(lactide) show adequate mechanical properties for use as bone substitute materials.

Porous composite materials made of poly(L, DL-lactide) and a ceramic component, alpha-tricalcium phosphate (alpha-TCP) or one of the rapidly resorbable glass ceramics, GB9N or GB14N, respectively, were developed to be used as bone substitutes. The present article describes the mechanical properties and the in vitro degradation characteristic of the different composite materials. The yield strength, the elastic modulus, and the molecular weight were measured after in vitro degradation up to 78 weeks. The initial strengths of the alpha-TCP composite (12.5 +/- 0.7 MPa) was higher than that of the GB9N and GB14N composites (8.3 +/- 0.2 MPa and 10.9 +/- 0.2 MPa, respectively). The initial elastic moduli of the composites were between 450 and 650 MPa. The mechanical properties remained constant until a degradation period of 26 weeks. Then they decreased continuously until they were completely lost at week 52. The molecular weight (M(w)) decreased steadily from 91,000 D in the case of the alpha-TCP composite and 78,000 D and 85,000 D in the case of the GB9N or GB14N composites, respectively, to about 10,000 D at week 78. It was concluded that the composites show adequate mechanical properties in the range of cancellous bone and a suitable degradation characteristic to be used as bone substitute materials.     

The in situ synthesis of biphasic calcium phosphate scaffolds with controllable compositions, structures, and adjustable properties

In this study, biphasic calcium phosphate (BCP) porous scaffolds with controllable phase compositions, controllable macropore percentages, and thus adjustable properties were in situ prepared by sintering a series of composites consisted of calcium phosphate cement (CPC) and porous resin negative mold made from rapid prototyping (RP) technique. The CPC pastes were formed by mixing a powder mixture of tetracalcium phosphate and anhydrous dicalcium phosphate with liquid phase of diluted phosphate acid solution. Results show that the phase composition was easily adjustable by controlling both weight ratio of the powder mixture to the liquid phase (P/L) and concentration of the liquid phase. The macropore structure of the BCP scaffold can be regulated by using different RP negative molds. Through in vitro compressive strength (CS) and immersion tests, it was demonstrated that both macropore percentage and phase composition played important roles in the CS and also the dissolving rates of the scaffolds. As the macropore percentage of the scaffold increased, its CS decreased but the dissolving rate increased; also, as the weight ratio of hydroxyapatite to tricalcium (HA/TCP) in the scaffold increased, the CS first increased and then decreased but the dissolving rate uniformly decreased. The CS values of the BCP scaffolds with a HA/TCP weight ratio of 59:41 were 5.84 +/- 1.16 MPa for a total porosity of approximately 67.67% containing a macropore percentage of 30%, and 3.34 +/- 0.79 MPa for a total porosity of approximately 70.90% containing a macropore percentage of 50%, respectively, comparable to the corresponding levels of human cancellous bone (2-12 MPa).