β-磷酸三钙/聚乳酸叠层生物材料的理化性能

本文研究了β—磷酸三钙／聚乳酸叠层复合支架在体外37℃生理盐水中的降解过程，内容包括材料的重量、力学强度、聚乳酸分子量、材料周围环境的pH值、Ca^2 浓度等参数随时间的变化，并证实材料理化特性适合于骨组织工程支架材料的要求。支架材料的生物相容性评价实验结果表明骨髓基质细胞与支架间有良好的亲和性。     

聚-L-乳酸/β-磷酸三钙复合物生物可吸收骨折内固定棒的体内降解和组织相容性

将β-磷酸三钙(β-TCP)与聚-L-乳酸(PLLA)复合得到PLLA/β-TCP复合材料,用注射成型方法制备出可吸收骨折内固定棒,然后通过分子量、质量变化、扫描电镜观察、弯曲强度变化和组织学方法等研究可吸收骨折内固定棒的体内降解过程。结果表明,降解初期聚乳酸的分子量有大幅度下降,重量损失滞后。随着降解的进行,可吸收棒表面逐渐粗糙,内部逐渐出现微孔和小“沟壑”,弯曲强度从初始的151MPa下降至12周的106MPa。组织学分析显示,PLLA/β-TCP复合材料具有良好的组织相容性。     

磁性多孔磷酸三钙陶瓷的生物相容性分析

一种新型骨移植替代材料,磁性多孔磷酸三钙陶瓷(MPTCP)可能为骨缺损的治疗开辟一条新途径.为检验其生物相容性及毒性,我们用40只大白鼠(雌雄各半)进行了以下实验:将平均重量为15.3mg的该材料颗粒植入大白鼠双侧股骨近端人工钻孔中,一半动物仅钻孔不植入材料作为对照组.术后30天作动物体重、器官重、器官/体重以及血液学、临床生化、X线拍片、普通切片、扫描电镜检查.结果表明,该材料生物相容性好,无异物及毒性反应,且材料周围骨细胞增生活跃,并向陶瓷孔隙中生长.故认为,MPTCP是一种很值得探讨的骨移植替代材料.     

磷酸单酯改性β-磷酸三钙的研究

以磷酸单酯(PL)为表面改性剂，对β-磷酸三钙(β-TCP)粉末进行表面改性研究，通过测试β-TCP粉末改性后的水性接触角，观察SEM颗粒形貌及分析XPS表面元素和基团，表明：PL改性后的β-TCP微粒具有良好的疏水性和分散性，且颗粒粒径在0．2～1．2μm之间。     

不饱和聚磷酸酯/β-磷酸三钙复合材料修复骨缺损的实验研究

目的 观察以不饱和聚磷酸酯（UPPE）／β-磷酸三钙（β—TCP）制备的复合材料对骨缺损的修复效果。方法利用溶液浇铸法技术制备UPPE／β-TCP复合材料。将36只新西兰大白兔随机等分为两组,手术造成右股骨髁部腔洞状直径8mm骨缺损,实验组植入直径8mm复合材料,对照组作空白对照。通过影像学、组织学、图像分析技术观察骨缺损的修复效果及材料的降解情况。结果影像学结果表明,实验组术后8周新生骨痂将缺损修复,术后16周骨痂塑形良好;对照组术后16周内均无骨痂形成,缺损未修复。组织学显示,实验组术后8周复合材料降解成较大的数块,有新骨形成;术后16周正常骨与材料之间形成贯通的髓腔;对照组为少量纤维组织连接。术后8周和16周材料降解率分别是30．3％和52．2％。结论以不饱和聚磷酸酯／β-磷酸三钙制备的骨修复材料对骨缺损具有良好的修复作用。     

低强度脉冲超声波对β－磷酸三钙与兔骨髓基质干细胞相容性的影响

目的研究低强度脉冲超声波(LIPUS)对-磷酸三钙(-TCP)与兔骨髓基质干细胞(BMSCs)相容性的影响。方法抽取新西兰白兔的骨髓,分离纯化获取BMSCs,加入条件培养基和-TCP体外混合培养并随机分为两组,一组应用LIPUS对BMSCs每天作用20分钟,另一组作为对照未予作用。通过倒置相差显微镜观察细胞增殖分化情况,分别于1周、2周、3周后停止LIPUS作用,在扫描电镜下观察细胞生长情况,评估TCP与BMSCs的相容性。结果BMSCs在两组-TCP表面生长繁殖良好。混合培养1周、2周时,实验组TCP表面BMSCs数目较对照组明显增多,并具有统计学意义(<0.05)。混合培养3周时,实验组TCP表面BMSCs数目与对照组相比无统计学差异(﹥0.05)。结论LIPUS可以提高培养早期-TCP和BMSCs的生物相容性,而对于培养晚期TCP和BMSCs的生物相容性无明显影响。     

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。     

β-磷酸三钙陶瓷多孔结构厚度对释药过程影响的体外研究

目的探讨β-磷酸三钙(β-TCP)陶瓷多孔结构厚度对释药过程的影响。方法制备贮药腔直径3 mm和8mm多孔β-TCP载体,通过扫描电镜、力学强度检测等表征载体结构,采用填充法构建药物缓释系统,以磷酸盐缓冲液(PBS)和小牛血清(CS)为洗脱介质,分析体外利福平释放特性。结果在体外PBS中缓释40周后,β-TCP载体多孔结构平均孔径为(614.6±214.4)μm,较缓释前增大40.10%±48.87%(P0.05);平均孔内连接径为(128.3±38.5)μm,较缓释前增大84.33%±55.32(P0.05)。贮药腔直径3mm和8mm多孔β-TCP浸泡40周后,纵向压缩强度分别为(0.62±0.07)MPa、(0.41±0.05)MPa(P0.05),较缓释前同比下降75.81%±8.06%、73.17%±9.76%(P0.05)。贮药腔直径3mm和8 mm多孔β-TCP在体外PBS中40周累积释药量分别为(234.87±31.75)mg、(289.02±38.18)mg(P0.05),累积释药率分别为78.29%±10.58%、96.34%±12.73%(P0.05)。利福平在CS中累计释放量高于PBS。结论β-TCP多孔结构厚度能够控制药物释放,多孔β-TCP载体负载利福平后在体外能够缓释长达40周以上,有望用于脊柱结核术后椎体缺损的治疗。     

可注射性UPPE/β-TCP复合材料的制备及其细胞相容性实验研究

目的：探讨可注射性UPPE／β-TCP（不饱和聚磷酸酯邝一磷酸钙）复合材料的制备及其细胞生物相容性。方法：制备UPPE／β-TCP复合材料并测量其理化性质；原代培养小鼠骨髓基质细胞（MSCs），采用浸提法制备UPPE／β-TCP培养基浸提液，用MTr法测定细胞增值率并进行细胞毒性分级；将MSCs与复合材料混合培养并用扫描电镜观察。结果：UPPE／β-TCP复合材料的最大压缩强度和压缩模量分别为94．36±6．96MPa、2096．93±92．86MPa，水接触角为27°；培养的细胞大量增殖，细胞形态良好，UPPE／β—TCP复合材料的毒性分级为0级或者1级，通过扫描电镜观察MSCs与复合材料混合培养的情况，发现MSCs可以黏附生长。结论：制备的可注射性UPPE／β-TCP复合材料有良好的理化性质；体外生物相容性良好。     

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％。     

生物活性玻璃/胶原蛋白/磷酸丝氨酸复合支架材料的制备及其细胞相容性探讨

通过冷冻干燥方法制备出仿生型多孔结构的溶胶-凝胶生物活性玻璃(BG)/胶原蛋白(COL)/磷酸丝氨酸(PS)支架材料,并评价了小鼠胚胎成骨细胞系细胞在BG、BG-COL、BG-COL-PS支架材料上的生长、黏附、增殖情况。MTT法测结果显示,细胞在材料表面贴附、增殖良好,且细胞在BG-COL-PS支架材料生长增殖要明显好于BG-COL、BG支架材料。BG-COL-PS支架材料有可能成为一种新型的骨组织工程支架材料。     

静电纺胶原/丝素复合微纳米纤维的制备及细胞相容性研究

采用静电纺丝技术制备胶原/丝素复合微纳米纤维,对其理化性能进行表征并观察其细胞相容性。以六氟异丙醇(HFIP)为溶剂,将胶原和丝素以 100:0.70:30.50:50.30:70.0:100的质量比共混进行电纺。制备的五种材料经戊二醛蒸汽交联12 h。采用扫描电镜、红外光谱、X射线衍射、热重分析和拉伸力学性能测试等方法对其理化性能进行表征。材料种植成纤维细胞后,通过扫描电镜和噻唑兰(MTT)比色法观察其细胞相容性。结果显示制备的纤维平均直径在550~1 100 nm之间,随着丝素含量的增加纤维平均直径增加。交联后纤维的β化程度、结晶度和热稳定性均有一定提高,且随着丝素含量的增加提高越明显;交联后材料的力学性能优于交联前;当丝素含量为70%时,纤维膜的平均断裂强度为(8.70±1.05) MPa,高于其它配比的纤维膜。细胞在材料表面生长状态良好;丝素含量为70%组的细胞粘附和增殖高于其它组,与细胞培养板相比无显著性差异,表明其细胞相容性良好,可望成为一种新型的组织工程支架材料。     

蛛丝蛋白/聚己内酯/壳聚糖复合纳米纤维支架与内皮细胞的相容性

将RGD-重组蛛丝蛋白(pNSR32)、聚己内酯(PCL)和壳聚糖(CS)共混,应用静电纺丝技术制备复合纳米纤维支架(pNSR32/PCL/CS),进行细胞相容性的初步研究.选择体外细胞培养法,以内皮细胞为种子细胞,应用MTT比色法评价材料浸提液细胞毒性及材料对内皮细胞粘附、生长及增殖的影响,细胞免疫荧光法检测与支架复...     

人工气管组分材料胶原蛋白/羟基磷灰石体外细胞毒理学研究

细胞毒性和细胞相容性是生物材料应用于临床所遇到的首要问题。将胶原蛋白作为载体与羟基磷灰石混合制成人工气管的组分材料，通过体外实验研究其细咆毒性和细胞相容性，为临床应用作前期准备。采用体外细胞培养法、MTT比色法评价胶原蛋白和羟基磷灰石复合材料对培养细胞L-929的细胞形态、生长和增殖的影响，同时采用溶血试验评价该复合材料是否对红细咆的功能和代谢产生不良反应。结果显示，胶原蛋白和羟基磷灰石复合材料对体外培养的细胞形态不构成损害，对其生长和增殖无明显抑制作用，细胞毒性为0级；溶血率为1．85％，低于5％的国家标准，在体外不引起溶血反应。实验表明，胶原蛋白和羟基磷灰石复合材料具有良好的细胞相容性，属无毒级生物材料，其作为人工气管组分材料应用于临床具有可行性和安全性。     

Properties of Antibacterial Polypropylene/Nanometal Composite Fibers

Melt spinning of polypropylene fibers containing silver and zinc nanoparticles was investigated. The nanometals were generally uniformly dispersed in polypropylene, but aggregation of these materials was observed on fiber surface and in fiber cross-sections. The mechanical properties of the resulted composite fibers with low concentration of nanometal were comparable to those for the control PP yarns. Extruded composite fibers that contained 0.72% silver and 0.60% zinc nanoparticles had outstanding antibacterial efficacy as documented by the percentage count reduction growth of Escherichia coli and Staphylococcus aureus. Fibers containing silver particles had improved antistatic properties.     

草鱼鱼皮胶原蛋白与NIH3T3成纤维细胞的相容性

体外检测草鱼鱼皮酸溶性胶原蛋白(FASC)的细胞相容性。采用MTT实验,检测不同浓度的FASC溶液或FASC涂层胶对NIH3T3成纤维细胞增殖能力的影响(n=6);利用transwell趋化实验,检测不同浓度的FASC溶液对成纤维细胞的趋化作用(n=3);利用transwell侵袭实验,检测不同浓度FASC涂层胶的细胞通透性(n=3)。结果表明,FASC溶液浓度依赖性地促进NIH3T3成纤维细胞增殖,16 μg/mL的FASC溶液在48和96 h的增殖率分别为63.7%±7.9%和87.3%±8.7%,较对照组有显著性差异(P<0.001)。NIH3T3细胞能够在FASC涂层胶上生长,各实验组与对照组相比,增殖率均无显著性差异(P > 0.05)。趋化实验显示,FASC溶液各浓度梯度组与阴性对照组的趋化指数均有显著性差异(P < 0.05),提示FASC对成纤维细胞具有趋化作用。侵袭实验结果显示,成纤维细胞可以通过FASC涂层胶。实验证实,FASC与NIH3T3细胞具有良好的相容性。     

Tensile Tests of Collagen Fibers Obtained from the Rabbit Patellar Tendon

Tensile properties of collagen fibers of approximately 1 m in diameter were determined using a newly developed micro tensile test system for cells and fine fibrous biological tissues. The test system consists of a thermostatic test chamber, an inverted microscope, micromanipulators, a direct drive linear actuator, a cantilever-type load cell, and a video dimension analyzer (VDA). The fibers were isolated with a mechanical method from collagen fascicles (approximately 300 m in diameter) cut out from the rabbit patellar tendon. The ends of each fiber were attached to the tips of a pair of glass microtubes (15 to 20 m in outer diameter) using a cyanoacrylate adhesive. One of the microtubes was attached to the load cell; the other one was connected to the linear actuator which was utilized to stretch the fiber. Load applied to the fiber was measured with the load cell, while its elongation was determined with the VDA using the images of the edges of the adhesive as markers. Tangent modulus, tensile strength, and strain at failure of the tested fibers were 54.3± 25.1 MPa, 8.5± 2.6 MPa, and 21.6± 3.0%, respectively. These values were much different from those of collagen fascicles (300 m in diameter) cut out from the rabbit patellar tendon and also from those of the bulk patellar tendon (Trans. ASME, J. Biomech. Eng. 121, 124–294, 1999); for example, tensile strength and strain at failure of the fibers were approximately 50 and 200% of those of the fascicles, respectively. These results suggest that the mechanical interactions between fibers and between fibers and ground substances contribute much to the mechanical properties of collagen fascicles and bulk tendons.     

Activation of NLRP3 Inflammasome Complexes by Beta-Tricalcium Phosphate Particles and Stimulation of Immune Cell Migration in vivo

Beta-tricalcium phosphate (β-TCP) serves as a bone substitute in clinical practice because it is resorbable, biocompatible, osteointegrative, and osteoconductive. Particles of β-TCP are also inflammatory mediators although the mechanism of this function has not been fully elucidated. Regardless, the ability of β-TCP to stimulate the immune system might be useful for immunomodulation. The present study aimed to determine the effects of β-TCP particles on NLR family pyrin domain containing 3 (NLRP3) inflammasome complexes. We found that β-TCP activates NLRP3 inflammasomes, and increases interleukin (IL)-1β production in primary cultured mouse dendritic cells (DCs) and macrophages, and human THP-1 cells in caspase-1 dependent manner. In THP-1 cells, β-TCP increased also IL-18 production, and NLRP3 inflammasome activation by β-TCP depended on phagocytosis, potassium efflux, and reactive oxygen species (ROS) generation. We also investigated the effects of β-TCP in wild-type and NLRP3-deficient mice in vivo. Immune cell migration around subcutaneously injected β-TCP particles was reduced in NLRP3-deficient mice. These findings suggest that the effects of β-TCP particles in vivo are at least partly mediated by NLRP3 inflammasome complexes.     

Reinforcement of a Porous Collagen Scaffold with Surface-Activated PLA Fibers

A hybrid porous collagen scaffold mechanically reinforced with surface-activated poly(lactic acid) (PLA) fiber was prepared. PLA fibers, 20 μm in diameter and 1 mm in length, were aminolyzed with hexanediamine to introduce free amino groups on the surfaces. After the amino groups were transferred to aldehyde groups by treatment with glutaraldehyde, different amounts (1.5, 3, 5 and 8 mg) of surface-activated PLA fibers were homogeneously mixed with 2 ml type-I collagen solution (pH 2.8, 0.6 wt%). This mixture solution was then freeze-dried and cross-linked to obtain collagen sponges with surface-activated PLA fiber. Scanning electron microscopy observation indicated that the collagen sponges had a highly interconnected porous structure with an average pore size of 170 μm, irrespective of PLA fiber incorporation. The dispersion of surface-activated PLA fibers was homogeneous in collagen sponge, in contrast to unactivated PLA fibers. The compression modulus test results showed that, compared with unactivated PLA fibers, the surface-activated PLA fibers enhanced the resistance of collagen sponge to compression more significantly. Cytotoxicity assay by MTT test showed no cytotoxicity of these collagen sponges. L929 mouse fibroblast cell-culture studies in vitro revealed that the number of L929 cells attached to the collagen sponge with surface-activated PLA fibers, both 6 h and 24 h after seeding, was higher than that in pure collagen sponge and sponge with unactivated PLA fibers. In addition, a better distribution of cells infiltrated in collagen sponge with surface-activated PLA fibers was observed by histological staining. These results indicated that the collagen sponge reinforced with surface-activated PLA fibers is a promising biocompatible scaffold for tissue engineering.     

The Effects of Prestrain and Collagen Fibril Alignment on In Vitro Mineralization of Self-Assembled Collagen Fibers

Collagen fibers are under tension in most extracellular matrices both prior to and during normal loading. This tension not only provides mechanical advantages, but also appears to establish a loading basis for the stimulation of mechanochemical transduction processes. The presence of tensile loads applied to collagen fibers also results in physical alignment of the collagen fibrils along the tensile axis. This alignment may influence biological processes such as mineralization.

In this study we report a comparison between elastic and viscous stress-strain curves and mineral contents of self-assembled collagen fibers that were strained to 30% of their original lengths and then mineralized, and self-assembled collagen fibers that were not strained before being mineralized. We concluded that the application of strain changes the organization of the collagenous matrix and alters the calcium phosphate nucleation and/or growth in the matrix. In addition, when the mechanical behavior of collagen fibers is compared with mechanical data from mineralized turkey tendon, the results indicate that collagen fibril-to-fibril interactions present in turkey tendon appear to be more organized compared with self-assembled aligned collagen fibers. We concluded that organized collagen-collagen interactions appear to be an important characteristic required for elastic energy storage in tendon.