静电纺丝聚膦腈/明胶复合纤维支架的生物矿化行为

背景：虽然静电纺丝高分子纤维的生物矿化研究文章已不少见,但国内外尚无关于静电纺丝聚膦腈及其与明胶复合纤维的生物矿化研究报道。目的：考察聚膦腈/明胶复合纤维支架作为骨组织工程支架的可行性。方法：静电纺丝法构建生物可降解聚膦腈/明胶复合纤维支架,采用5倍模拟体液,并结合扫描电镜、X射线能谱、X射线光电子能谱、傅里叶变换红外光谱等手段,观察其生物矿化行为。结果与结论：与纯明胶的纤维膜相比,聚（丙氨酸乙酯-甘氨酸乙酯）膦腈（PAGP）和明胶混合溶液静电纺丝得到的复合纤维膜,经交联处理后仍能够保持良好的纤维形貌和多孔结构。在采用CO2平衡的改进5倍模拟体液中,纯PAGP和PAGP/明胶纤维表面沉积的矿物质都经历了片状二水合磷酸一氢钙前驱体的生成及其向羟基磷灰石转化的过程,但后者由于明胶成分的存在,整个过程发生发展的速度要明显快于前者。而对于纯明胶纤维,其在改进5倍模拟体液中浸泡24h后,所生成矿物质仍主要为羟基磷灰石的前驱体二水合磷酸一氢钙。说明复合纤维中,疏水性PAGP的引入不仅有利于纤维形貌的保持,还能抑制明胶的溶出,使PAGP/明胶复合纤维的矿化性能明显改善。     

气电纺纳米羟基磷灰石/聚羟基丁酸酯复合纤维支架对大鼠骨髓基质细胞成骨分化的影响

背景:利用静电纺丝技术制备的纤维支架材料具有类似于细胞外间质的形态和结构,且其独特的生产工艺可以很便捷地将功能性纳米颗粒复合入高分子纤维内,在制备组织工程支架方面具有独特的优势.目的:创新性地将物理共混法与气流-高压静电纺丝技术相结合,仿生构建纳米羟基磷灰石/聚羟基丁酸酯复合纳米纤维支架材料,评价其作为骨组织工程支架在体外的生物活性.设计、时间及地点:细胞学体外实验,于2008-03/2009-04在四川大学口腔疾病研究国家重点实验室完成.材料:按照预定参数进行气流-高压静电纺丝,分别制备气电纺纯聚羟基丁酸酯纤维支架及含质量分数为10%纳米羟基磷灰石的纳米羟基磷灰石,聚羟基丁酸酯复合纤维支架.方法:将大鼠骨髓基质细胞接种于纳米羟基磷灰石/聚羟基丁酸酯纳米纤维支架后进行体外培养(实验组),以接种于气电纺纯聚羟基丁酸酯纳米纤维支架为对照组,接种于细胞培养板为空白对照组.主要观察指标:通过RT-PCR检测连续培养14 d后细胞成骨分化标志物碱性磷酸酶、I型胶原和骨钙素的mRNA表达.结果:各组均能检测到3种成骨标志物碱性磷酸酶、I型胶原和骨钙素的mRNA表达.通过Quantity One软件分析计算目的条带吸光度值与内参β-actin条带吸光度值的比值,可以发现3种目的基因在实验组具有最高表达水平,其次为对照组,空白对照组的表达明显最弱.结论:气电纺纳米羟基磷灰石,聚羟基丁酸酯复合纤维支架可促进大鼠骨髓基质细胞成骨分化,证实其在体外具有优良的生物活性.     

纳米羟基磷灰石/聚己内酯复合大鼠骨髓间充质干细胞的生物相容性

背景:纳米羟基磷灰石/聚己内酯是一种具有优良生物相容性和生物活性的典型生物复合材料.目的:分析纳米羟基磷灰石/聚己内酯电纺薄膜作为组织工程骨支架的可行性.方法:采用静电纺丝技术制备纳米羟基磷灰石/聚己内酯电纺薄膜,将其与第3代 SD 大鼠骨髓间充质干细胞复合培养,在地塞米松、β-磷酸甘油钠、维生素C成骨诱导剂诱导下,诱导骨髓间充质干细胞向成骨细胞转化.结果与结论:纳米羟基磷灰石/聚己内酯支架具有合适的微孔结构,且孔道相互贯通.①倒置显微镜观察:复合培养7 d后细胞大部分为梭形,细胞开始分裂;14 d后,细胞生长比较旺盛,数量明显增多,细胞分泌基质并黏附于支架上.②扫描电镜观察:复合培养7 d后大量细胞位于支架孔隙内生长,增殖良好,细胞大多呈梭形,双极突起,形态较佳,呈立体状生长,并分泌基质,有纤维连接蛋白生成.表明纳米羟基磷灰石/聚己内酯支架具有良好的生物相容性,是骨组织工程的良好载体.     

电纺纳米羟基磷灰石/聚酯酰胺复合支架材料的制备及其细胞相容性

背景:采用静电纺丝技术将功能性无机纳米微粒复合高分子超细纤维,形成类细胞外基质结构和功能的复合支架材料是骨组织工程支架领域一个新的研究方向。目的:通过静电纺丝法构建纳米羟基磷灰石/脂肪族聚酯酰胺复合纤维支架材料,并初步考察其细胞相容性。方法:以静电纺丝法制备纳米羟基磷灰石/脂肪族聚酯酰胺超细纤维支架材料,通过扫描电镜、原子能谱等表面形貌的物相分析,进行细胞在复合材料上的形态学观察。结果与结论:通过静电纺丝法成功制备出纳米羟基磷灰石/脂肪族聚酯酰胺超细纤维复合材料,成骨细胞直接培养于材料上呈现良好生长行为,初步证实了复合支架材料的细胞相容性。说明静电纺丝技术在构建类骨细胞外基质结构和功能的仿生复合材料方面具有独特优势,电纺超细纤维复合材料有望成为新型的骨组织工程支架。     

聚酰胺-胺接枝聚膦腈的合成与结构表征

背景:当前大多数研究采用将生长因子或帮助细胞黏附生长的功能蛋白(如细胞黏附蛋白)直接接枝在支架材料表面的方式,这样接枝的功能蛋白质在外界环境下常常显得不稳定,进而容易分解.目的:制备能负载基因并可调节生物相容性及其性能的聚膦腈类组织工程支架材料.设计、时间及地点:单一样本观察,于2007-04/06在北京化工大学化工资源有效利用国家重点实验室完成.材料:六氯环三膦腈为宁波博源化工材料有限公司产品;丙氨酸乙酯盐酸盐为天人生化科技有限公司产品;甲胺盐酸盐为北京石鹰化工厂产品;丙烯酸甲酯为天津市博迪化工有限公司产品.方法:采用两步分子设计方案:第1步先以聚膦腈为主链,制备出一种长链预聚物准备用于组织工程的超支化的支架材料,第2步在前一步的预聚物上接枝附有特定功能的基因片段,通过其原位表达的形式,编码所需的蛋白质和生长因子.首先制备生物相容性好、性能易于调控的丙氨基酸乙酯取代聚膦腈,随后采用分别与乙二胺和丙烯酸甲酯发生取代和加成的方法来制备超支化聚合物.主要观察指标:①丙氨酸乙酯取代聚膦腈(G0.5)的1H-NMR表征.②端氨基聚膦腈(G1.0)的13C-NMR表征.③端酯基聚膦腈(G1.5)的13C-NMR表征.结果:丙氨酸乙酯取代聚合物1H-NMR表征说明丙氨酸乙酯已经成功地接在聚膦腈上,此聚合物为所要得到的G0.5目标产物.超支化端氨基聚膦腈(G1.0)的13C-NMR谱图说明了氨基酯交换反应的发生及G1.0结构的形成.端酯基聚膦腈(G1.5)的13C-NMR表征说明加成反应的发生及G1.5结构的形成.结论:实验设计出用于组织工程的超支化聚膦腈支架材料,并合成了0.5,1.0,1.5代聚酰胺一胺型超支化聚膦腈聚合物,并进行了1H-NMR、13C-NMR结构表征,证实了合成聚酰胺一胺型超支化聚瞵腈的可行性.     

聚磷酸钙纤维/羟基磷灰石/明胶软骨组织工程支架材料的制备及性能★

背景:目前明胶基组织工程支架材料存在力学性能低、生物相容性差、降解速率难以控制等缺陷。目的:通过添加聚磷酸钙纤维和羟基磷灰石改善明胶支架材料的性能。方法:以自制聚磷酸钙纤维和羟基磷灰石为添加材料,明胶为基体材料,以戊二醛为交联剂,采用溶媒浇铸/粒子滤取技术制备配比为50/10/40的聚磷酸钙纤维/羟基磷灰石/明胶软骨组织工程支架复合材料。测试支架材料的物理力学性能,并观察其微观结构。结果与结论:采用溶胶凝胶法制得的羟基磷灰石粉末结晶程度较差,经900℃下煅烧0.5h后,可制得结晶程度较高的羟基磷灰石粉末。聚磷酸钙纤维/羟基磷灰石/明胶软骨组织工程支架材料具有三维、连通、微孔网状空间结构,孔隙率在65%-90%之间,满足软骨组织工程对其支架材料孔隙的要求。戊二醛的交联作用和聚磷酸钙纤维的增强作用,克服了明胶在制备多孔支架时容易收缩的缺点,制得高孔隙率三维连通的支架材料。     

新型纳米纤维支架的细胞生物相容性

背景:高孔隙率聚己内酯纳米纤维支架具有适合血管平滑肌细胞黏附、增殖的多级孔径结构,具有良好的细胞生物相容性.目的:探讨高孔隙率聚己内酯静电纺丝纳米纤维支架的细胞相容性.方法:根据支架的制作工艺不同分为传统支架组、新型纳米纤维支架组两组,另设单纯细胞组为对照组.采用组织块贴壁法体外原代培养兔主动脉平滑肌细胞并进行传代,用3～6代细胞作为实验用种子细胞.应用WST-1法测定平滑肌细胞黏附率、增殖力,光镜及扫描电镜观察细胞形态,评估支架的细胞生物相容性.结果与结论:高孔隙率聚己内酯纳米纤维支架对细胞形态无明显影响,新型支架上的种子细胞黏附、增殖及代谢活性情况较传统支架好.提示,高孔隙率聚己内酯静电纺丝纳米纤维支架具有较高的细胞相容性.     

电纺丝技术制备生物活性复合纤维支架及其体外降解性

背景：聚乳酸/羟基磷灰石类复合材料支架常用的制备方法主要有冷压法、粒子沥滤法、热致相分离法等,但是在增强材料界面的结合、调节材料的降解速率、改善材料的强度等方面仍不能满足要求。目的：制备左旋聚乳酸/羟基磷灰石复合纳米纤维支架。方法：采用静电纺丝法制备聚乳酸/羟基磷灰石复合纳米纤维支架。以扫面电镜对纤维的结构形态进行分析,并观察其在PBS中浸泡不同时间的体外降解过程。结果与结论：羟基磷灰石纳米粒子与聚乳酸/基体间存在化学键合,纳米粒子使纤维直径增大且表面粗糙程度增加,这种结构将有利于细胞在纤维膜上的伸展和和繁殖。羟基磷灰石的引入,抑制了聚乳酸降解过程中的自催化作用,减缓了聚乳酸的降解速度。说明电纺丝技术制备的聚乳酸/羟基磷灰石复合支架在组织工程支架材料方面具有潜在的应用前景。     

电纺丝技术制备生物活性复合纤维支架及其体外降解性

背景:聚乳酸/羟基磷灰石类复合材料支架常用的制备方法主要有冷压法、粒子沥滤法、热致相分离法等,但是在增强材料界面的结合、调节材料的降解速率、改善材料的强度等方面仍不能满足要求。目的:制备左旋聚乳酸/羟基磷灰石复合纳米纤维支架。方法:采用静电纺丝法制备聚乳酸/羟基磷灰石复合纳米纤维支架。以扫面电镜对纤维的结构形态进行分析,并观察其在PBS中浸泡不同时间的体外降解过程。结果与结论:羟基磷灰石纳米粒子与聚乳酸/基体间存在化学键合,纳米粒子使纤维直径增大且表面粗糙程度增加,这种结构将有利于细胞在纤维膜上的伸展和和繁殖。羟基磷灰石的引入,抑制了聚乳酸降解过程中的自催化作用,减缓了聚乳酸的降解速度。说明电纺丝技术制备的聚乳酸/羟基磷灰石复合支架在组织工程支架材料方面具有潜在的应用前景。     

静电纺丝聚乳酸复合物纳米纤维材料与小鼠神经干细胞的生物相容性

背景：聚乳酸聚乙醇酸支架材料广泛应用于组织工程学领域,但其细胞黏附性较差、缺乏活性功能基团以及疏水性较强等缺点限制了其进一步的发展和应用。目的：观察小鼠神经干细胞与静电纺丝聚乳酸聚乙醇酸/聚乙二醇共聚物纳米纤维支架材料的体外相容性。方法：自孕15 d CD-1小鼠胚胎大脑皮质分离培养小鼠神经干细胞。静电纺丝法制备聚乳酸聚乙醇酸和聚乳酸聚乙醇酸/聚乙二醇纳米纤维支架材料,扫描电镜观察材料结构;取第5代神经干细胞分别接种于聚乳酸聚乙醇酸和静电纺丝聚乳酸聚乙醇酸/聚乙二醇纳米纤维支架材料上,进行体外培养。结果与结论：扫描电镜检测显示,两种支架材料呈现相互交联的多孔网状结构。聚乳酸聚乙醇酸组和静电纺丝聚乳酸聚乙醇酸/聚乙二醇组纤维直径和孔隙率差异无显著性意义（P 〉0.05）。CCK-8检测显示,两种材料无明显细胞毒性。神经干细胞在支架材料中生长良好,两组吸光度值均随培养时间延长而增大,两组在培养1,3,5,7,9,11 d吸光度值差异均有显著性意义（P 〈0.05）。两组材料培养3,6,9 h,静电纺丝聚乳酸聚乙醇酸/聚乙二醇组的细胞黏附率明显高于聚乳酸聚乙醇酸组（P 〈0.05）。Hoechst染色显示两组细胞核质均染,形态正常,静电纺丝聚乳酸聚乙醇酸/聚乙二醇组细胞数量明显多于聚乳酸聚乙醇酸组（P 〈0.05）。扫描电镜观察显示,与聚乳酸聚乙醇酸组相比,静电纺丝聚乳酸聚乙醇酸/聚乙二醇组神经干细胞在支架上的生长情况和基质分泌更好。结果说明,静电纺丝法制备的静电纺丝聚乳酸聚乙醇酸/聚乙二醇纳米纤维支架细胞生物相容性良好,安全无毒,具备合适的孔径和孔隙率,适宜神经干细胞生长,是一种适用于组织工程优质的支架载体。     

A biocompatible polypyrrole membrane for biomedical applications

Polypyrrole (PPy) is the most widely investigated electrically conductive biomaterial. However, because of its intrinsic rigidity, PPy has only been used either in the form of a composite or a thin coating. This work presents a pure and soft PPy membrane that is synergically reinforced with the electrospun polyurethane (PU) and poly-l-lactic acid (PLLA) fibers. This particular reinforcement not only renders the originally rather fragile PPy membrane easy to manipulate, it also prevents the membrane from deformation in an aqueous environment. Peel and mechanical tests confirmed the strong adhesion of the fibers and the significantly increased tensile strength of the reinforced membrane. Surface electrical conductivity and long-term electrical stability were tested, showing that these properties were not affected by the reinforcement. Surface morphology and chemistry were analyzed with scanning electron spectroscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR). Material thermal stability was investigated with thermogravimetric analysis (TGA). Finally, the adhesion and proliferation of human skin keratinocytes on the membrane were assessed by Hoechst staining and the methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay. In conclusion, this membrane proves to be the first PPy-based soft conductive biomaterial that can be practically used. Its electrical conductivity and cytocompatibility promise a wide range of biomedical applications.

A reinforced soft polypyrrole membrane.     

Humidity sensor based on poly(lactic acid)/PANI–ZnO composite electrospun fibers

The electrospinning technique has been successfully used to prepared micro-fibers of the poly(lactic acid)/polyaniline–zinc oxide (PLA/PANI–ZnO) composite. The polyaniline–zinc oxide (PANI–ZnO) nanocomposites are synthesized by hydrothermal and in situ polymerization methods. X-ray diffraction techniques are used to study the structural properties of the PLA/PANI–ZnO composite fibers and the PANI–ZnO nanocomposite. The average crystallite size of the PANI–ZnO nanocomposite is found to be 36 nm. The morphology and diameter of the composite fibers are analyzed by scanning electron microscopy (SEM). The average fiber diameter of the pure poly(lactic acid) (PLA) fiber is around 2.5 μm and that of the PLA/PANI–ZnO composite fiber is around 1.4 μm. Differential scanning calorimetry (DSC) provides the thermal properties of the PLA/PANI–ZnO composite fibers. The melting temperature (T_m) for the pure PLA is observed at 149.3 °C, and it is shifted to 153.0 °C for the PLA/PANI–ZnO composite fibers. The enhanced thermal properties of the composite fibers are due to the interaction between the polymer and the nanoparticles. The water contact angle measurements probe the surface hydrophilicity of the PLA/PANI–ZnO composite fibers. The role of the PANI–ZnO nanocomposite on the sensing behavior of PLA fibers has also been investigated. The humidity sensing properties of the composite fiber based sensor are studied in the relative humidity (RH) range of 20–90% RH. The experimental results show that the composite fiber exhibited good response (85 s) and recovery (120 s) times. These results indicate that the one-dimensional (1D) fiber structure enhances the humidity sensing properties.

The electrospinning technique has been successfully used to prepared micro-fibers of the poly(lactic acid)/polyaniline–zinc oxide (PLA/PANI–ZnO) composite for humidity sensor application.     

明胶联合壳聚糖纤维对磷酸钙骨水泥力学性能的影响

背景：已有多种纤维被用于提高磷酸钙骨水泥的强度及抗断裂性能。目的：了解明胶联合壳聚糖纤维对磷酸钙骨水泥力学性能的影响,寻找较为合适的配比。方法：采用2×4析因设计,将质量比为0（蒸馏水）,5%的明胶,体积比为0,10%,30%和50%的壳聚糖纤维分别混入磷酸钙骨水泥,检测复合物的抗弯曲强度,扫描电子显微镜观察各组试样断口形态并进行电子能谱分析。结果与结论：各明胶组间抗弯强度差异有非常显著性意义（P〈0.001）;各体积比纤维间抗弯强度差异有非常显著性意义（P〈0.001）,其中5%明胶和30%壳聚糖纤维构成的复合物抗弯曲强度最大,达12.31MPa。以蒸馏水为液相的磷酸钙骨水泥固化后,表面可见不规则颗粒,平均微孔直径小于5μm,添加明胶后颗粒似乎黏在一起,微孔直径与前者相似,但是数目少于前者。磷酸钙骨水泥-5%明胶-30%纤维复合物的断口扫描可见拔出纤维的表面黏附有大量颗粒,磷酸钙骨水泥-蒸馏水-30%纤维复合物拔出纤维表面的颗粒明显减少。表明明胶与壳聚糖纤维可提高磷酸钙骨水泥的抗弯曲强度,5%明胶和30%壳聚糖纤维为这种增强模式较为合适的比例。     

Preparation, characterization and in vitro release of gentamicin from PHBV/wollastonite composite microspheres.

Composite microspheres have been prepared from bioactive wollastonite (W) and biodegradable poly (hydroxybutyrate-polyhydroxyvalerate) (PHBV) in the present study. Gentamicin was encapsulated into the microspheres by the absorption method and the in vitro release of the gentamicin from the microspheres was performed in distilled water, modified simulated body fluid (SBF) and phosphate buffered saline (PBS) at 37 degrees C for 22 days, respectively. The results showed that the release behavior of gentamicin from PHBV/W composite microspheres was similar to that from the pure PHBV microspheres when the experiment was performed in distilled water. However, in the PBS and SBF solutions, gentamicin released from the PHBV/W composite microspheres at a relatively lower rate as compared to that of the pure PHBV microspheres and 90% of the total amount of gentamicin released from the composite microspheres after soaking for 22 days, which was much longer than that for the release of the same amount gentamicin from the pure PHBV microspheres (8 days). Scanning electron microscopy (SEM) and energy-dispersive spectrometer (EDS) analysis on the microspheres after release in SBF and PBS revealed that a microporous apatite layer was formed on the composite microspheres surface, which resulted in a controlled release behavior of the gentamicin from the PHBV/W composite microspheres. All of these results provided the possibility that the PHBV/W composite microspheres could be applied as alternative drug controlled release systems, especially as bone fillings for bone repair due to their advantages of controlled releasing antibiotics and apatite-formation ability, through which the implanted microspheres could chemically bond to the surrounding tissue in vivo.     

Physicochemical properties and performance of graphene oxide/polyacrylonitrile composite fibers as supercapacitor electrode materials

Graphene oxide derived from palm kernel shells (rGOPKS) and polyacrylonitrile (PAN) were electrospun into composite fiber mats and evaluated as supercapacitor electrode materials. Their morphologies and crystalline properties were examined, and chemical interactions between rGOPKS and PAN were investigated. The diameters of individual fibers in the rGOPKS/PAN composite mats ranged from 1.351 to 1506 μm and increased with increasing rGOPKS content. A broad peak centered near 23° in the X-ray diffraction (XRD) pattern of rGOPKS corresponded to the (002) planes in graphitic carbon. Characteristic rGOPKS and PAN peaks were observed in the XRD patterns of all the composite fibers, and their Fourier-transform infrared (FTIR) spectra indicated hydrogen bond formation between rGOPKS and PAN. The composite fiber mats had smooth and homogeneous surfaces, and they exhibited excellent flexibility and durability. Their electrochemical performance as electrodes was assessed, and a maximum specific capacitance of 203 F g⁻¹ was achieved. The cycling stability of this electrode was excellent, and it retained over 90% of its capacitance after 5000 cycles. The electrode had an energy density of 17 W h kg⁻¹ at a power density of 3000 W kg⁻¹. Dielectric results showed a nanofiber composite dielectric constant of 72.3 with minor leakage current (tan δ) i.e., 0.33 at 51 Hz. These results indicate that the rGOPKS/PAN composite fibers have great promise as supercapacitor electrode materials.

Graphene oxide derived from palm kernel shells (rGOPKS) and polyacrylonitrile (PAN) were electrospun into composite fiber mats and evaluated as supercapacitor electrode materials.     

Hybrid composite of Nafion with surface-modified electrospun polybenzoxazine (PBz) fibers via ozonation as fillers for proton conducting membranes of fuel cells

Nafion was investigated for its compatibility in the preparation of hybrid composites with electrospun Polybenzoxazine (PBz) surface-modified fibers by evaluating the effects on the surface and structure of the composite. A PBz fiber mat was first crosslinked by thermal treatment after electrospinning to enhance the mechanical integrity of the fibers prior to modification. Further surface modification via free radical ozonation was carried out by potentiating oxygen-based functional groups of hydroxyl radicals (–OH) onto fibers'' exposed surfaces. The sequential modifications by crosslinking and ozone treatment were evaluated by analyzing surface properties using XPS, ATR-FTIR and water contact angle which determined the enhanced properties of the fibers that were beneficial to the target functionality. Electron spectroscopy confirmed that fibers'' surfaces were changed with the new surface chemistry without altering the chemical structure of PBz. The presence of higher oxygen-based functional groups on fibers'' surfaces based on the resulting atomic compositions was correlated with the change in surface wettability by becoming hydrophilic with contact angle ranging from 21.27° to 59.83° compared to hydrophobic pristine PBz fibers. This is due to electrophilic aromatic substitution with hydroxyl groups present on the surfaces of the fibers endowed by ozonation. The resulting surface-modified fiber mat was used for the preparation of composites by varying two process parameters, the amount of Nafion dispersion and its homogenization and curing time, which was evaluated for compatibility and interaction as fillers to form hybrid composites. The analyses of SEM images revealed the effects of shorter homogenization and curing time on composites with rougher and wrinkled surfaces shown on the final hybrid composite''s structure while decreasing the amount of Nafion at the same homogenization time but longer curing time showed its influence on improvement of compatibility and surface morphology.

Nafion compatibility in the preparation of hybrid composites with electrospun Polybenzoxazine (PBz) surface-modified fibers via ozonation by evaluating the effects on the surface and structure of the composite.     

Effect on thermal stability of microstructure and morphology of thermally-modified electrospun fibers of polybenzoxazines (PBz) blended with sulfur copolymers (SDIB)

Simple modification by thermal treatment is the commonly used approach to enhance the performance of electrospun fibers. This was investigated in the thermal treatment of polybenzoxazine (PBz) fibers blended with sulfur copolymers (SDIB) to determine the effect of varying treatment conditions on the microstructure and morphology of PBz fibers with the effect of incorporating sulfur functional groups on resulting properties. Mechanical properties of PBz are greatly improved by thermally-induced ring-opening polymerization (ROP) of the oxazine ring. Blending with sulfur copolymers (SDIB) could have beneficial effects on endowed features on fibers but could also affect the resulting properties of SDIB-blended PBz fibers during crosslinking reactions. Fiber mats were fabricated by electrospinning of PBz (10 wt%) blended with SDIB (10 wt%). Physical modification with varying conditions of sequential thermal treatment were evaluated and compared to the conditions applied on pristine PBz fibers. Changes in morphology and microstructure of fibers after modification were analyzed through scanning electron microscopy (SEM) while elemental compositions were identified after varying the conditions of thermal treatment. Adjustment of treatment conditions using two-step temperature sequential thermal treatment with higher temperatures of 160 °C and 240 °C showed significant changes in microstructure and morphology of fibers. Lower temperatures of 120 °C and 160 °C exhibited microstructure and morphology of fibers which affected the fiber diameter and fiber networks. Cross-sectional SEM images also confirmed the adversed effect of high-temperature treatment conditions on fibrous structures while low-temperature treatment retained the fibrous structures with more compact and stiff fiber networks. SDIB-blended PBz fibers were also evaluated by TGA and DSC to correlate the changes in structure and morphology with the thermal stability and integrity of blended SDIB/PBz fibers as compared to pristine PBz with the effect of change in treatment conditions. Fiber strength indicated slower weight loss for blended fibers and higher onset temperature of degradation which resulted in more thermally stable fibers.

Microstucture and morphology of thermally-modified electrospun fiber of PBz blended with SDIB that enhanced structural satbility and integrity.     

钛合金种植体表面制备的生物活性膜

背景:传统的仿生方法通常采用常规模拟体液和1.5倍模拟体液,其缺点就在于涂层生长过于缓慢,生长周期长达数周甚至几个月.目的:探讨3倍模拟体液诱导Ti-6Al-4V合金表面快速形成类羟基磷灰石涂层的能力.设计、时间及地点:体外生物学分析.实验于2008-11/2009-03在中国科学院金属研究所完成.材料:Ti-6Al-4V合金片由陕西省宝鸡市博达金属材料有限公司提供.方法:将经过预处理的Ti-6Al-4V合金浸泡在37℃的3倍模拟体液中,为保持浸泡液成分的恒定,溶液每24 h更换1次,共浸泡3 d.主要观察指标:用扫描电镜、X射线衍射仪和红外光谱仪分析涂层的形貌、相及元素组成.结果:扫描电镜观察样品浸泡1 d时,表面被沉积膜覆盖,局部区域有较大颗粒状的晶体出现.浸泡3 d时,表面完全被沉积膜覆盖,且有大量颗粒状或鳞片状晶体出现,晶体沉积以某一区域为核心,持续生长.生成物主要由Ca,P,O,C等元素组成,但是没有检测到Al,V等元素的存在.X射线衍射仪和红外光谱仪分析浸泡3 d时Ti-6Al-4V合金表面制备的生物活性膜主要成分为羟基磷灰石.结论:使用3倍模拟体液可以快速诱导Ti-6Al-4V合金表面类羟基磷灰石的沉积,显著缩短涂层形成的时间.