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。     

A hybrid zinc-calcium-silicate polyalkenoate bone cement

A novel bone cement composed of sintered zinc-calcium-silicate phosphate and hybrid polyalkenoates has been developed. Synthesis and formulation of glass fillers, monomers and polymers as well as formulation of the cement were described. The effects of sintering, polymer content, glass powder/polymer liquid (P/L) ratio and comonomer on compressive strength (CS) and curing time (CT) were investigated. The effects of P/L ratio and comonomers on shrinkage as well as exotherm were also studied. Results show that the experimental cement was 61% higher in CS, 10% lower in diametral tensile strength, 35% lower in flexural strength, 62% less in exotherm, and 68% less in shrinkage, compared to conventional polymethylmethacrylate cement. With increasing polymer content and P/L ratio in the cement formulation CS of the cement increased but CT decreased. Curing time, shrinkage and exotherm of the cement decreased with increasing P/L ratio. It appears that this novel cement may be a potential candidate for orthopedic restoration if its biological performance is good and formulation is optimized.     

重组人骨形态发生蛋白2/骨修复材料的制备与性能

BACKGROUND: It has become a hotspot to prepare the bone repair material that exhibits natural bone structure and is used in combination with biological factors. OBJECTIVE: To prepare the recombinant human bone morphogenetic protein-2 (rhBMP-2)/bone repair material, and to evaluate its capacities of release, activity and ectopic osteoinduction. METHODS: A collagen-binding domain was added to the N-terminal of native rhBMP-2 that allowed bind to collagens in the bone repair material. Then, rhBMP-2/bone repair material was obtained through freeze-dried method. The releasing ability of rhBMP-2 in vitro was assayed by ELISA. C2C12 cell lines were loaded to the composite material with 0.25, 0.5 and 1 µg rhBMP-2, respectively. Afterwards, alkaline phosphatase activity was detected at 72 hours. The composite materials with 0, 2, 5 and 10 µg rhBMP-2 were implanted into the quadriceps of Sprague-Dawley rats, respectively. Alkaline phosphatase activity and the newly formed bone were detected at 2 and 4 weeks after implantation. The CY-7-labeled composite material was implanted into the quadriceps of Sprague-Dawley rats to observe its stability. RESULTS AND CONCLUSION: Substantially no rhBMP-2 from the rhBMP-2/bone repair material was released within 45 days. The alkaline phosphatase activity of C2C12 was in a rise with the increased concentration of rhBMP-2. The stability of the composite material in vivo was better, the alkaline phosphatase activity and ectopic bone formation increased as the concentration of rhBMP-2 rose. To conclude, the rhBMP-2/bone repair material preserves the stability of rhBMP-2, and improves ectopic osteoinduction ability.     

Preparation, characterization, and properties of nano-TiO2/silk fibroin hybrid films by sol-gel processing

By sol-gel processing, the regenerated nano-TiO(2)/SF (silk fibroin) hybrid films were synthesized using different ratios of TiO(2) to SF. The experimental results revealed that the nano-TiO(2) particles were well dispersed in the regenerated SF. The diameter of the nano-TiO(2) particles processed by sol-gel method was about 80 nm. Through Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray energy dispersive spectrometer (EDS), Thermogravimetric analysis (TGA), and Derivative thermogravimetry (DTG), the structures and properties of these hybrid films were characterized. The XRD measurement indicated that the crystal structures of the hybrid films were transited from typical Silk I to typical Silk II. However, it was found that excessive increase in the content of nano-TiO(2) led to the breakage of the crystal structures of the hybrid films. The FTIR and EDS analysis showed that new bonds were formed between the nano-TiO(2) particles and the SF. Through TGA and DTG, it was demonstrated that the heat transition temperature of the hybrid films was also enhanced.     

Pore distribution and material properties of bone cement cured at different temperatures

Implant heating has been advocated as a means to alter the porosity of the bone cement/implant interface; however, little is known about the influence on cement properties. This study investigates the mechanical properties and pore distribution of 10 commercially available cements cured in molds at 20, 37, 40 and 50 °C. Although each cement reacted differently to the curing environments, the most prevalent trend was increased mechanical properties when cured at 50 °C vs. room temperature. Pores were shown to gather near the surface of cooler molds and near the center in warmer molds for all cement brands. Pore size was also influenced. Small pores were more often present in cements cured at cooler temperatures, with higher-temperature molds producing more large pores. The mechanical properties of all cements were above the minimum regulatory standards. This work shows the influence of curing temperature on cement properties and porosity characteristics, and supports the practice of heating cemented implants to influence interfacial porosity.     

胶原多糖基纳米羟基磷灰石仿生骨支架材料的研制

目的依据仿生原理制备新型的胶原多糖基纳米羟基磷灰石（HA）复合骨支架材料,并与成骨细胞复合培养,检测其细胞相容性。方法以胶原分子与透明质酸钠的交联产物为模板,调制钙磷盐在液相中沉积其上,得到矿化胶原多糖基复合材料;采用液相分离法与少量聚乳酸复合进一步制备成为三维多孔支架,使用成骨细胞（Mc3T3-E1）接种于该支架上培养。用X—ray衍射、扫描电镜、万能材料测试机等对材料进行观察和测试分析;并用倒置相差显微镜、荧光显微镜、扫描电镜、CCK-8细胞计数试剂盒、碱性磷酸酶（ALP）活性测定等观察和分析细胞在支架材料中的生长、分化情况。结果胶原多糖基纳米HA仿生复合材料的晶粒度较低,晶体极为细小,与天然骨中羟基磷灰石的组装结构类似;该复合支架为多孔状,孔隙率约82％,孔径大小为200～650μm;抗压性能好,成骨细胞可在其上贴附、生长和繁殖,并表现出较高的成骨活性。结论所制备的胶原多糖基纳米HA仿生骨支架材料,无论从组分和结构上均与天然松质骨类似,与成骨细胞相容性好,可望成为较理想的骨组织工程支架材料。     

Microencapsulation of 2-octylcyanoacrylate tissue adhesive for self-healing acrylic bone cement

Here, we report the first phase of developing self-healing acrylic bone cement: the preparation and characterization of polyurethane (PUR) microcapsules containing a medical cyanoacrylate tissue adhesive. Capsules were prepared by interfacial polymerization of a toluene-2,4-diisocyanate-based polyurethane prepolymer with 1,4-butanediol to encapsulate 2-octylcyanoacrylate (OCA). Various capsule characteristics, including: resultant morphology, average size and size distribution, shell thickness, content and reactivity of encapsulated agent, and shelf life are investigated and their reliance on solvent type and amount, surfactant type and amount, temperature, pH, agitation rate, reaction time, and mode of addition of the oil phase to the aqueous phase are presented. Capsules had average diameters ranging from 74 to 222 μm and average shell thicknesses ranging from 1.5 to 6 μm. The capsule content was determined via thermogravimetric analysis and subsequent analysis of the capsules following up to 8 weeks storage revealed minimal loss of core contents. Mechanical testing of OCA-containing capsules showed individual capsules withstood compressive forces up to a few tenths of Newtons, and the contents released from crushed capsules generated tensile adhesive forces of a few Newtons. Capsules were successfully mixed into the poly(methyl methacrylate) bone cement, surviving the mixing process, exposure to methyl methacrylate monomer, and the resulting exothermic matrix curing. ? 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.     

煅烧骨/壳聚糖复合材料的制备及表征

文题释义：                                                                                                     天然骨：主要由无机的羟基磷灰石和有机的胶原成分构成,并具有一定的力学性能。以羟基磷灰石和磷酸三钙为主的磷酸盐材料拥有良好的骨传导性和部分骨诱导性,能够与宿主的骨直接发生骨结合,已成为目前临床应用最多的骨移植材料。 锻烧骨：是经高温锻烧异体动物骨所获得的无机材料,主要成分是羟基磷灰石,其钙磷比接近于人骨,拥有极好的生物相容性和优越的骨引导性。与人工合成的羟基磷灰石相比,不用考虑煅烧骨材料的结构形貌,而且材料来源广泛、制作成本低。 背景：壳聚糖具备优异的理化性能与良好的生物相容性,但其缺乏骨结合的生物活性,需要与其他材料复合用于骨组织修复中。 目的：将煅烧骨与壳聚糖复合,分析其理化性能和细胞毒性。 方法：采用溶液共混法制备煅烧骨与壳聚糖质量比分别为1/2、1/1、2/1的复合材料,表征3种复合材料的理化性能。在第5代小鼠成纤维细胞 L929中分别加入3种复合材料浸提液,CCK-8法检测复合材料的细胞毒性。 结果与结论：①X射线衍射和红外光谱显示,3种复合材料的主要成分均为羟基磷灰石与β-磷酸三钙,并且随着煅烧骨比例的增加,复合材料中的羟基磷灰石/β-磷酸三钙的特征衍射峰逐渐增强;②扫描电镜显示,煅烧骨颗粒较均匀地分散于壳聚糖介质中;③随着煅烧骨比例的增加,复合材料的抗压强度逐渐降低;④培养7 d时,3种复合材料浸提液中的细胞生长良好,形态无明显变化;培养9 d的时间内,3种复合材料浸提液中的细胞相对增殖率均在90%以上,细胞毒性均为1级,符合生物材料的安全标准;⑤结果表明,煅烧骨/壳聚糖复合材料具备良好的结构特征、理化性能及合适的抗压强度,并且安全无毒。 ORCID: 0000-0003-3519-4485(廖健) 中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

高黏度骨水泥与传统骨水泥治疗骨质疏松性椎体压缩性骨折的疗效比较

目的比较高黏度骨水泥与传统聚甲基丙烯酸甲酯(PMMA)骨水泥治疗骨质疏松性椎体压缩性骨折的疗效,探讨高黏度骨水泥在临床应用中的优势。方法选择2009年7月~2013年7月治疗并获得随访160例骨质疏松性椎体压缩性骨折患者,其中男性64例,女性96例;年龄61~88岁,平均年龄69.1岁。分高黏度骨水泥组[91例(112个椎体)]和传统骨水泥组[69例(86个椎体)]。高黏度骨水泥组,采用以色列Disc-O-Tech公司Confidence骨水泥,施行经皮椎体成形术(PVP);传统骨水泥组,采用PMMA骨水泥,施行PVP。术后对比两组患者视觉疼痛模拟评分(VAS)、责任椎Cobb角的恢复情况及术后骨水泥渗漏情况,并随访观察。结果高黏度骨水泥组与传统骨水泥组VAS评分(1.5±0.8vs1.4±0.9)比较差异无统计学意义(P0.05);高黏度骨水泥组Cobb角恢复优于传统骨水泥组(13.6°±3.1°vs 19.8°±3.0°),差异有统计学意义(P0.05);高黏度骨水泥组渗漏率远低于传统骨水泥组(19.6%vs 41.9%),差异有统计学意义(P0.05)。所有患者术后获得3~48个月(平均16个月)随访,其中3例出现神经根症状,所有患者未出现感染、肺栓塞等并发症。结论高黏度骨水泥与传统PMMA骨水泥相比,在纠正椎体Cobb角及降低骨水泥渗漏发生率方面效果更佳,明显提高了PVP的安全性及有效性。     

The effect of the monomer-to-powder ratio on the material properties of acrylic bone cement

The procedure percutaneous vertebroplasty consists of injecting polymethylmethacrylate cement into vertebral bodies for the treatment of osteoporotic compression fractures and tumors of the spine. Clinicians practicing vertebroplasty commonly alter the mixture of monomer-to-powder recommended by the manufacturer in an effort to decrease viscosity and increase the working time. The purpose of the current study was to measure the effect of varying the monomer-to-powder ratio on the compressive material properties (compressive modulus, yield stress, and ultimate compressive strength) of the cement Simplex P (Stryker-Howmedica-Osteonics, Rutherford, NJ). Cylindrical specimens were prepared using monomer-to-powder ratios of 0.45 to 1.00 mL/g and tested in compression. Peak compressive material properties occurred at the mixture ratio recommended by the manufacturer (0.5 mL/g) but decreased as the ratio of monomer to powder was increased. The material properties of specimens cured for 1 hour were significantly less than those for specimens cured for 24 hours. The monomer-to-powder ratio affects the compressive material properties of cement. The clinical significance of these results with respect to vertebroplasty is yet to be determined.     

Preparation of a bioactive and degradable poly(epsilon -caprolactone)/silica hybrid through a sol-gel method

A bioactive and degradable poly(epsilon -caprolactone)/silica hybrid was synthesized for the application as a bone substitute. Triethoxysilane end capped polyepsilon -caprolactone) was prepared by the reaction with alpha,omega-hydroxyl poly(epsilon -caprolactone) and 3-isocyanatopropyl triethoxysilane using 1,4-diazabicyclo[2,2,2,]octane as a catalyst. It was then co-condensed with tetraethyl orthosilicate and calcium nitrate tetrahydrate via a sol-gel method. The bioactivity of the poly(epsilon -caprolactone)/silica hybrid was assessed using simulated body fluid and low crystalline apatite was successfully formed on its surface after soaking for 1 week at 36.5 degrees C. Its biodegradability was evaluated in the phosphate buffered saline and the degradability was mostly come from the poly(epsilon -caprolactone) phase in the hybrid. It means that this hybrid is likely to be applicable to a bioactive and degradable bone substitute.     

Polymer--calcium phosphate cement composites for bone substitutes

The use of self-setting calcium phosphate cements (CPCs) as bioresorbable bone-replacement implant materials presently is limited to non-load-bearing applications because of their low compressive strength relative to natural bone. The present study investigated the possibility of strengthening a commercially available CPC, alpha-BSM, by incorporating various water-soluble polymers into the cement paste during setting. Several polyelectrolytes, poly(ethylene oxide), and the protein bovine serum albumin (BSA) were added in solution to the cement paste to create calcium phosphate-polymer composites. Composites formulated with the polycations poly(ethylenimine) and poly(allylamine hydrochloride) exhibited compressive strengths up to six times greater than that of pure alpha-BSM material, with a maximum value reached at intermediate polymer content and for the highest molecular weight studied. Composites containing BSA developed compressive strengths twice that of the original cement at protein concentrations of 13-25% by weight. In each case, XRD studies correlate the improvement in compressive strength with reduced crystallite dimensions, as evidenced by a broadening of the (0,0,2) reflection. This suggests that polycation or BSA adsorption inhibits crystal growth and possibly leads to a larger crystal aspect ratio. SEM results indicate a denser, more interdigitated microstructure. The increased strength was attributed to the polymer's capacity to bridge between multiple crystallites (thus forming a more cohesive composite) and to absorb energy through plastic flow.     

Preparation of poly(L-lactic acid)-polysiloxane-calcium carbonate hybrid membranes for guided bone regeneration

A novel poly(L-lactic acid) (PLLA)/calcium carbonates hybrid membrane containing polysiloxane was prepared using aminopropyltriethoxysilane (APTES) for biodegradable bone-guided regeneration. Carboxy groups in the PLLA made a chemical bond with amino groups in APTES, resulting in the formation of the hybrid membrane. The polysiloxane-hybridized PLLA was an amorphous phase. The membrane formed hydroxycarbonate apatite (HCA) on its surface after 3d of soaking in simulated body fluid (SBF). X-ray energy-dispersive spectroscopy showed that the HCA layer includes Si with Ca and P. After soaking the membrane in SBF, almost no Si was present in SBF. The membrane is expected to be a satisfactory substrate for the formation of the silicon-containing HCA layer using the SBF-soaking method. A result of osteoblast-like cellular proliferation on the membrane and the membrane coated with silicon-containing HCA showed no cell toxicity. The membrane coated with silicon-containing HCA had much higher cell-proliferation ability than the membrane.     

Synthesis of partial-stabilized cement (PSC) via sol-gel process

Biomaterials have been widely used to prepare synthetic vascular grafts over the past thirty years, but the inherent thrombogenicity of their surface can lead to graft failure. Endothelial progenitor cells (EPC) are circulating premature cells able to differentiate in either myocardial or endothelial cells (EC). The therapeutic potential of these cells and its easy obtaining technique are important reasons why these cells could be used to improve the performance of vascular grafts. In this study, two different stages of differentiation of EC derived from EPC (EC(1) and EC(2)) were characterized and cultured on poly(epsilon-caprolactone) (PCL) films treated with NaOH (PCL-NaOH). We investigated by immunolabeling the expression of CD31, von Willebrand factor (vWF), and endothelial nitric oxide synthase (eNOS) in these cells during the differentiation process. The proliferation, cell cycle, and mitochondrial function of EC(2) cultured on PCL-NaOH were evaluated at different times. The effect of this biomaterial on the nitric oxide (NO) content was also measured. The mature EC obtained from circulating progenitor cells (EC(2)) showed an appropriate growth and functionality on NaOH-treated films. They conserved their capacity to define vessel-like structures in culture and increased their basal NO production. These results underline the potential usefulness of these EC(2) to get a functional endothelialization of polymers with applications in vascular tissue engineering.     

Repair of segmental bone defects using bioactive bone cement: comparison with PMMA bone cement.

We developed a bioactive bone cement (BABC) that consists of apatite and wollastonite containing glass ceramic (AW-GC) powder and bisphenol-A-glycidyl dimethacrylate (Bis-GMA) based resin. In the present study, the effectiveness of the BABC for repair of segmental bone defects under load-bearing conditions was examined using a rabbit tibia model. Polymethylmethacrylate (PMMA) bone cement was used as a control. A 15-mm length of bone was resected from the middle of the shaft of the tibia, and the tibia was fixed by two Kirschner wires. The defects were replaced by cement. Each cement was used in 12 rabbits; six rabbits were sacrificed at 12 and 25 weeks after surgery, and the tibia containing the bone cement was excised and tension tested. At both the intervals studied, the failure loads of the BABC were significantly higher than those of the PMMA cement. The BABC was in direct contact with bone, whereas soft tissue was observed between the cement and bone in all PMMA cement specimens. Results indicated that the BABC was useful as a bone substitute under load-bearing conditions.     

Preparation and antibacterial effects of Ag-SiO2 thin films by sol-gel method

In the present study, silver-doped silica thin films were successfully prepared by sol-gel method to apply for antibacterial materials. The starting solution was prepared from 1:0.24:3.75:2.2 molar ratios of Si(OC2H5)4):AgNO3:H2O:C2H5OCH2CH2OH and then the pH value controlled at 3 with 0.5 N HNO3 solution. The formation of silver-doped glassy silica thin films at various temperatures was investigated through infrared spectroscopy, ultraviolet-visible, scanning electron microscopy and X-ray diffraction. From these analysis data, it was found that silver ions were completely trapped in the silica matrix and their reduction could be achieved at 600 degrees C annealing temperature. The antibacterial effects of silica thin films against Escherichia coli and Staphylococcus aureus were examined by film attachment method. The coating films had an excellent antibacterial performance.     

新型可吸收骨水泥的制备及其应用于小牛椎体标本压缩性骨折椎体成形术的生物力学研究

目的 探讨聚富马酸丙二醇酯（PPF）/β-磷酸三钙（β-TCP）制备新型可吸收骨水泥的配方及其应用于小牛椎体标本压缩性骨折椎体成形术的生物力学性能研究。方法 采用两步法制备PPF,使用凝胶渗透色谱仪测量PPF的数均分子量、重均分子量及聚合度分布指数,使用MR氢谱对PPF进行结构分析。将制备好的PPF与β-TCP按照10∶1、5∶1、3∶1、2∶1配制不同热交联反应体系,制备4种不同配方的PPF/β-TCP可吸收骨水泥,选择抗压强度和压缩模量均较高的骨水泥进行后续实验。选取2~3岁健康小牛腰椎L₁~L₄节段标本4具,分离出16个椎体,使用牙托粉填平每个椎体的椎板凹陷部位,测量每个椎体的受力面积。选择椎体受力面积相近的10个椎体,按数字表法随机分为PPF/β-TCP组和甲基丙烯酸甲酯（PMMA）组,每组5个。PMMA组和PPF/β-TCP组椎体使用MTS-858力学机器制备压缩性骨折模型,对比2组完成模型制备时的椎体高度、抗压强度和刚度。PPF/β-TCP组和PMMA组分别使用PPF/β-TCP骨水泥和标准PMMA骨水泥对压缩骨折模型行椎体成形术,对比2组骨水泥注入量,术后椎体高度、椎体恢复百分比,椎体抗压强度、刚度。结果 PPF数均分子量为1 637±55,重均分子量为1 741±68,聚合分布指数为1.06。MR氢谱结构分析提示反应产物为PPF。配方1~4 PPF/β-TCP可吸收骨水泥抗压强度分别为（53.5±1.5）、（63.2±0.4）、（97.9±5.5）、（100.8±3.2）MPa,压缩模量分别为（0.97±0.04）、（1.05±0.05）、（1.10±0.10）、（0.45±0.18）GPa。选取压缩模量与抗压强度均高的配方3 PPF/β-TCP可吸收骨水泥用于椎体成形术。PPF/β-TCP组和PMMA组小牛椎体标本的椎体体积、高度、受力面积差异均无统计学意义（P值均>0.05）。PPF/β-TCP组和PMMA组的椎体压缩性骨折后高度、椎体成形术后椎体高度以及椎体高度恢复百分比差异均无统计学意义（P值均>0.05）。组内比较：PPF/β-TCP组椎体压缩性骨折椎体成形手术前后椎体抗压强度分别为（2 282±341）N和（1 848±219）N,椎体刚度分别为（215±27）N/mm和（182±15）N/mm,差异均无统计学意义（t=2.14、2.13,P值均>0.05）;PMMA组压缩性骨折椎体成形手术前后抗压强度分别为（2 350±289）N和（3 105±452）N,椎体刚度分别为（221±26）N/mm和（296±37）N/mm,差异均有统计学意义（t=2.81、3.21,P值均<0.05）。组间比较：PPF/β-TCP组与PMMA组术中骨水泥注入量差异无统计学意义（P>0.05）;PPF/β-TCP组与PMMA组发生压缩性骨折时椎体抗压强度和刚度差异均无统计学意义（P值均>0.05）,椎体成形术后椎体抗压强度和刚度PMMA组均大于PPF/β-TCP组,差异均有统计学意义（t=4.99、5.61,P值均<0.05）。结论 PPF与β-TCP按照3∶1配制的可吸收骨水泥具有与人椎体力学性能相近、交联温度低等特点。在治疗小牛椎体压缩性骨折模型时,PPF/β-TCP可吸收骨水泥与PMMA骨水泥术中注入量相近,两者恢复椎体高度的效果相当;且PPF/β-TCP可吸收骨水泥注入后椎体力学性能优于注入PMMA骨水泥者,具有替代PMMA骨水泥治疗椎体压缩性骨折的潜力。     

复合表面活性剂处理生物源性骨组织作为骨移植材料的生物安全性研究

目的 应用新型的表面活性剂处理生物源性骨组织,对其进行脱细胞效果及生物安全性评价,以期得到一种更安全、可靠的骨植入材料。方法2种阴离子表面活性剂ABS（十二烷基苯磺酸钠）和AES（脂肪醇聚氧乙烯醚硫酸钠）以及蒸馏水以重量比13：7：80的比例配制复合表面活性剂。以新鲜的牛松质骨为原料,复合表面活性剂脱脂脱细胞的两步法工艺,制备新型生物源性骨植入材料。对其进行组织学和表面超微结构观察,同时对表面活性剂处理的生物源性骨植入材料进行急性全身毒性试验、溶血试验、细胞毒性试验的生物安全性评价。通过骨长期植入试验观察表面活性剂生物源性骨的生物相容性和生物降解性。采用吸光度测量法界定骨材料中表面活性剂的残留量。结果复合表面活性剂生物源性骨颜色呈乳白色,无肉眼可见杂质,组织学及超微结构观察可见骨陷窝内细胞结构消失,骨小管空虚,胶原纤维排列整齐。生物安全性实验表明：按GB／T16886．11—1997急性全身毒性试验合格,溶血试验〈5％,细胞毒性试验0级。复合表面活性剂生物源性骨组织中表面活性剂的残留量低于0．1g／L。骨长期植入实验表明：4周时可见骨组织周围纤维组织生成,骨小梁内有细胞爬入,植入材料与宿主骨融合良好。8周时植入材料部分被机体吸收,24周后被机体完全吸收。结论复合表面活性剂处理的生物源性骨移植材料具有良好的生物相容性和生物降解性,是一种安全、可靠的骨植入材料。     

Bone marrow modified acrylic bone cement for augmentation of osteoporotic cancellous bone

The use of polymethylmethacrylate (PMMA) cement to reinforce fragile or broken vertebral bodies (vertebroplasty) leads to extensive bone stiffening. This might be one reason for fractures at the adjacent vertebrae following this procedure. PMMA with a reduced Young's modulus may be more suitable. The goal of this study was to produce and characterize PMMA bone cements with a reduced Young's modulus by adding bone marrow. Bone cements were produced by combining PMMA with various volume fractions of freshly harvested bone marrow from sheep. Porosity, Young's modulus, yield strength, polymerization temperature, setting time and cement viscosity of different cement modifications were investigated. The samples generated comprised pores with diameters in the range of 30-250 μm leading to porosity up to 51%. Compared to the control cement, Young's modulus and yield strength decreased from 1830 to 740 MPa and from 58 to 23 MPa respectively by adding 7.5 ml bone marrow to 23 ml premixed cement. The polymerization temperature decreased from 61 to 38 °C for cement modification with 7.5 ml of bone marrow. Setting times of the modified cements were lower in comparison to the regular cement (28 min). Setting times increased with higher amounts of added bone marrow from around 16-25 min. The initial viscosities of the modified cements were higher in comparison to the control cement leading to a lower risk of extravasation. The hardening times followed the same trend as the setting times. In conclusion, blending bone marrow with acrylic bone cement seems to be a promising method to increase the compliance of PMMA cement for use in cancellous bone augmentation in osteoporotic patients due to its modified mechanical properties, lower polymerization temperature and elevated initial viscosity.     

Bioactive poly(2-hydroxyethylmethacrylate)/silica gel hybrid nanocomposites prepared by sol-gel process

A hybrid of poly(2-hydroxyethylmethacrylate) (pHEMA), a polymer widely employed for biomedical applications, and silica gel, exhibiting a well-known bioactivity, was produced by sol-gel. The amount of the inorganic precursor, tetraethoxysilane (TEOS), was mixed to the organic monomer, so as to have a final concentration of 30% (w/w) of silica gel to the mass of polymer. The nanocomposite was characterized for its composition by thermogravimetric (TG) analysis, swelling behavior, glass transition temperature using differential thermal analysis (DTA), morphology through scanning electron microscopy (SEM), and bioactivity using FT-IR spectroscopy, SEM, and energy dispersive system (EDS). The nanocomposite showed phase separation between the polymer and the silica gel, improved thermal stability and swelling properties and higher glass transition temperature than pHEMA. Moreover, bioactive SiO(2) gel nanoparticles promoted apatite formation on the surface of the modified hydrogel, when it was soaked in SBF. Therefore, the obtained bioactive nanocomposite can be used to make bioactive scaffold for bone engineering.