Preparation and Characterization of PDLLA/ Chondroitin Sulfate/Chitosan Scaffold for Peripheral Nerve Regeneration

A novel bioactive and bioresorbable PDLLA/chondroitin sulfate/chitosan scaffold was prepared via layer-by-layer(LBL) electrostatic-self-assembly (ESA) and the thermally induced phase separation (TIPS) technique. Chondroitin sulfate and chitosan were alternately deposited on the activated PDLLA substrate.The deposition process was monitored by UV-Vis absorbance spectroscopy. After frozen and lyophilized, the scaffold was characterized by attenuated total reflection (ATR)-FT-IR, XPS, SEM and AFM. The results showed that the scaffold was modified uniformly with a dense inner layer with few detectable pores and a porous sponge outer layer with the pore size about 5 μm, there was an obvious across section and the average thickness of each layer was about 9.4 nm.     

Preparation and Characterization of a Novel PDLLA/ Chondroitin Sulfate/Chitosan Asymmetry Film

A novel bioactive and bioresorbable asymmetry film was prepared. The PDLLA membrane was activated by 1, 6-hexanediamine to obtain a stable positive charge surface. Chondroitin sulfate and chitosan were then deposited on activated PDLLA membrane via layer-by-layer （LBL） electro-static assembly （ESA） technique. The deposition process was monitored by UV-Vis absorbance spectroscopy. The composite membrane was frozen lyophilized to form the asymmetry film and characterized by attenuated total reflectic （ATR）-FT-IR, XPS and SEM. The experimental results show that a stable 1, 6-hexanediamine layer on PDLLA substrate based on the aminolysis of the polyester and the layer thickness increase linearly first with the increase of the deposited layers, and then increases slowly due to the layer interpenetration. The test results of ATR-FT- IR and SEM show the asymmetry film is modified uniformly with a dense inner layer and a porous sponge outer tayer.     

Preparation and Charactcrization of a Novel PDLLA/Chondroitin Sulfate/Chitosan Asymmetry Film

A novel bioactive and bioresorbable asymmetry film was prepared,The PDLLA membrane was activated by 1,6-hexanediamine to obtain a stable positive charge surface.Chondroitin sulfate and chitosan were then deposited on activated PDLLA membrane via layer-by-layer(LBL)electro-static assembly (ESA)technique.The deposition process was monitored by UV-Vis absorbance spectroscopy.The composite membrane was frozen lyophilized to form the asymmetry film and characterized by attenuated total reflectic (ATR)-FT-IR,XPS and SEM.The experimental results show that a stable 1,6-hexanediamme layer on PDLLA substrate based on the aminolysis of the polyester and the layer thickness increase linearly first with the increase of the deposited layers,and then increases slowly due to the layer interpenetration.The test results of ATR-FT- IR and SEM show the asymmetry film is modified uniformly with a dense inner layer and a porous sponge outer layer.     

壳聚糖/羧甲基壳聚糖止血膜的制备与表征

针对壳聚糖止血膜柔韧性差的问题,以丙三醇和酚磺乙胺作为改性剂,采用溶液浇膜的方法制备了不同组成配比的壳聚糖(CS)/羧甲基壳聚糖(CMCS)止血膜,并评价了CS/CMCS止血膜拉伸性能和止血效果.丙三醇的引入可使CS/CMCS止血膜的断裂伸长率提高4~7倍,尽管其拉伸强度也降低了70%.丙三醇改性的CS/CMCS=8/2载药止血膜具有较好的拉伸强度(10.4±0.9 MPa)和断裂伸长率(50.4±4.5%);与未加入酚磺乙胺的CS/CMCS止血膜相比,酚磺乙胺的离子交联作用使CS/CMCS载药止血膜的拉伸强度提高55%,而断裂伸长率仅降低24%.止血评价结果表明经丙三醇改性的CS/CMCS=8/2止血膜均能使血液发生分离的时间明显缩短,并具有促使血液凝结形成黑色血块的能力.     

离子交换法分离纯化猪硫酸软骨素的研究

研究离子交换法直接从猪鼻骨酶解液中分离纯化猪硫酸软骨素的工艺,并与传统酶解-氧化法进行比较.采用阳离子交换树脂对猪鼻骨酶解液进行分离纯化,以树脂对蛋白和硫酸软骨素的吸附率为指标,筛选得到一种能从酶解液中有效分离硫酸软骨素的树脂,并研究了温度、NaCl浓度和上样流速等因素对分离效果的影响.研究表明:HZ-016型阳离子交换树脂能从猪鼻骨酶解液中分离纯化硫酸软骨素,优化后的工艺条件:室温25℃,上样质量浓度20.5 mg/mL,上样流速1.0 mL/min,最大上样量1 BV(Bed Volume).与传统酶解-氧化法相比,收率提高6.5％,产品质量分数提高5.6％,杂蛋白含量降低28.6％,且工艺条件温和、乙醇耗量低和操作简单,具有良好的产业化应用前景.     

PDLLA/HA/FK506复合神经导管的制备及体外降解性能

以聚乳酸（PDLLA）为基材、纳米羟基磷灰石（HA）为添加剂、加入免疫抑制剂FK506，用溶剂挥发法制备PDLLA／HA/FK506复合神经导管。通过观察复合导管在磷酸缓冲溶液中降解时pH值变化、质量损耗及材料微观形貌，研究了该复合导管的体外降解性能。结果表明：加入适量纳米羟基磷灰石可以改善聚乳酸降解的酸性问题并提高其力学强度。免疫抑制剂FK506的加入对导管材料的降解性能有一定的影响。PDLLA/HA／FK506复合神经导管具有良好的降解性能。     

壳聚糖/明胶防术后黏连膜的制备和表征

采用溶液浇注法制备了壳聚糖/明胶防术后黏连共混膜.扫描电镜发现共混膜没有发生明显的相分离,随着明胶含量的增加,共混膜的断裂伸长率、吸水率和降解速率提高,而抗张强度略有下降.共混膜湿态下的最大抗张强度为17.3 MPa,最大断裂伸长率为99%,最大吸水率为123%.动物试验表明共混膜能抑制成纤细胞的生长,具有较好的防黏连作用.实验表明,通过壳聚糖与明胶共混达到了两者生理功能协同及理化性能改善的效果,能满足防术后黏连的实际应用需要.     

Evaluation of PLGA/chitosan/HA conduits for nerve tissue reconstruction

A micro-envioment for nerve cells and tissue growth were designed and constructed via surface modification of poly(L-lactide-co-glycolide)(PLGA) with chitosan and hydroxyapatite(HA). The poly(L-lactide-co-glycolide)/chitosan/hydroxyapatite (PLGA/chitosan/HA) conduits were manufactured by a combined solvent casting and particulate leaching technique. The conduits were highly porous with an interconnected pore structure and 76.5% porosity. Micropores with 50–100 micrometer diameter were formed in the conduits. In vivo application of PLGA/chitosan/HA conduits for reconstruction of 10 mm sciatic nerve defect was assessed by the walking track analysis, the quantifying of the wet weight of tibialis anterior muscle and the histological assessment. The conduits in host rats in vivo can not only be an effective in promoting regenerating of nerves but can also lead to favorable nerve functional recovery. Funded by the National Natural Science Foundation of China(No.50774096)     

壳聚糖为负载的纳米硒的制备

报道了以壳聚糖为负载,通过还原型谷胱甘肽和亚硒酸钠的反应制备纳米硒的方法.采用光谱法、扫描电镜和X射线衍射法对产物进行了表征,研究了反应时间、反应物浓度、洗涤溶剂等对产物颗粒大小、形貌的影响.     

Preparation and characterization of chitosan microsphere loading bovine serum albumin

To optimize the preparation process of chitosan microspheres and study its loading capacity, chitosan microsphere was prepared by crosslinking with glutaraldehyde, and bovine serum albumin (BSA) was absorbed onto chitosan microsphere. Scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FITR), TA instruments and zeta potentiometer analyzer were used to characterize the parameters with respect to size, thermal characters, morphology, and zeta potential of the microspheres. The loading capability and in vitro release tests were carried out. The results showed that chitosan microsphere with particle size less than 10 μm and positively charged (+25.97±0.56 mV) can be obtained under the aldehyde group to amino group ratio at 1:1. A loading capacity of BSA at 28.63±0.15 g/100 g with corresponding loading efficiency at 72.01±1.44% was obtained for chitosan microsphere. In vitro test revealed a burst release followed by sustained-release profile.     

Evaluation of apatite-coated chitosan microspheres for bone regeneration

The apatite-coated chitosan microspheres were fabricated by incubating chitosan in five times simulated body fluid. The apatite deposited on the microspheres was similar to natural bone mineral, as demonstrated by scanning electron microscopy, X-ray diffraction spectra and Fourier transformed-infrared spectroscopy analyses. Rat bone marrow-derived mesenchymal stem cells （BMSCs） were seeded on apatite- coated microspheres to investigate the effect of this scaffold on cell proliferation and differentiation. BMSCs seeded on uncoated microspheres were served as a control. In vivo experiment was evaluated by transplanting the microspheres loaded with or without BMSCs in 5-mm cranial defects of Wistar rats. Bone regeneration was investigated via micro-CT and histological analysis. It was found that apatite-coated chitosan microspheres could significantly promote the proliferation and alkaline phosphatase activity of BMSCs compared with uncoated microspheres. Histological slices and Micro-CT images at 8 weeks revealed much better regeneration of bone in the apatite-coated microspheres loaded with BMSCs than the control. In addition, the defect filled with pure microspheres induced little new bone formation. Our findings suggest that the apatite-coated chitosan microspheres scaffold is a promising carrier of stem cells for cranial bone tissue engineering.     

羧甲基壳聚糖的制备及应用

利用壳聚糖制备羧甲基壳聚糖,对羧甲基壳聚糖的制备条件进行优化,在最佳工艺路线下制备的羧甲基壳聚糖取代度在0.65以上.将制备的羧甲基壳聚糖用于处理工业废水,探讨改性后的壳聚糖与壳聚糖的性能差异.结果表明,羧甲基壳聚糖较壳聚糖有良好的脱色性能,脱色率达到43%,较壳聚糖效果较好,但化学需氧量(COD)去除率相比,相差不大.     

Preparation and self-assembly of chitosan/carbon microsphere composite

Carbon-based films were synthesized by self-assembly of chitosan-encapsulated carbon microsphere (CMS@CS) composite. First, carbon microspheres (CMSs) prepared by chemical vapor deposition were modified by HNO3 and H2O2. Second, oxidized CMSs were modified by chitosan (CS). Finally, CMS@CS was self-assembled by vertical deposition, in which suspension concentration and deposition temperature on the quality of self-assembling film were investigated. Field emission scanning electron microscopy, atomic force microscopy, X-ray diffraction, thermogravimetry, and Fourier transformation infrared spectrometry were employed to characterize the morphology and structure of the samples. The results show that CMSs modified by CS had uniform particle size and good dispersion, CMS@CS was self-assembled into a dense film, the film thickened with increasing suspension concentration at fixed temperature, and more ordered film was obtained at 1 wt% of suspension concentration and 50 ℃. The ultraviolet-visible absorption spectra show that the absorbance of CMS@CS film grew steadily with increasing suspension concentration and that the CMSs with oxygen-containing groups have a good assembling performance to form composite films with CS.     

医用SiO2气凝胶/壳聚糖复合材料的制备

用环境干燥法,通过静电作用制备了SiO2气凝胶/壳聚糖复合材料.SiO2气凝胶为基体,乙醇水溶液为分散介质,三聚磷酸钠为强电解质.采用扫描电镜、红外光谱仪分析其形貌和组成,并实验研究了此复合材料对药物庆大霉素（Gen）的担载能力.结果表明,这种SiO2气凝胶/壳聚糖复合材料对药物包覆率为17.32%.     

Chitosan—L- lactic acid scaffold for the regeneration of peripheral nerve and its NGF release properties

Chitosan—L-lactic acid composite scaffold for the regeneration of peripheral nerve is obtained by grafting L-lactic acid onto the amino groups in chitosan with combined vacuum freezer drier. The composite scaffold was characterized by ATR-FTIR and SEM. The scaffold has a better graft efficiency and has a dense inner layer and a loose outer layer with porous structure, and the pore size is about 100 μm. The NGF release properties of the scaffold were investigated. The experimental results showed that, at the 1st day, 15.2 ng of NGF on average was released from the scaffold. From day 2 to day 10, the release rate obviously slowed down and 1.64 ng of NGF was released on average every day. After 10 days, the release rate was slower and 10.3 ng of NGF was released on average every day. After 60 days, NGF could also maintained a certain concentration. These properties show that the scaffold is a better carrier for NGF which can be more advantageous to the regeneration of the damaged peripheral nerve. As a result, this composite scaffold would be an ideal candidate for the regeneration of damaged peripheral nerve.     

医用SiO_2气凝胶/壳聚糖复合材料的制备

用环境干燥法,通过静电作用制备了SiO2气凝胶/壳聚糖复合材料。SiO2气凝胶为基体,乙醇水溶液为分散介质,三聚磷酸钠为强电解质。采用扫描电镜、红外光谱仪分析其形貌和组成,并实验研究了此复合材料对药物庆大霉素(Gen)的担载能力。结果表明,这种SiO2气凝胶/壳聚糖复合材料对药物包覆率为17.32%。     

磁性壳聚糖微球的制备及其性能

用共沉淀法制备纳米级Fe3O4磁流体,并对其用油酸进行表面改性.采用化学交联法,在分散有磁流体的壳聚糖溶液中,加入适量的戊二醛交联剂,制得内核为磁性Fe304,外层包有壳聚糖的纳米级的磁性壳聚糖复合微球.考察了壳聚糖质量浓度、NaOH滴加量及搅拌速度等因素对磁性壳聚糖微球粒径、粒径分布以及形貌等对复合过程的影响,确定了...     

Preparation and Degradation Characteristics of Poly （d,l-lactide） Composite Films

PDLLA/CHI/β-TCP/NGF composite films were prepared by a solvent evaporation method. The degradation characteristics of the poly （d, l-lactide） composite films were studied in vitro and in vivo. The acidity produced by poly （d, l-lactide） materials was not obvious. Adding chitosan and β-TCP can relieve the acidity problem and improve strength performance of films. The NGF has influences on the degradation characteristics of films. It is verified that PDLLA/CHI/β-TCP/NGF composite films prepared by solvent evaporation method have excellent degradation characteristics. It can be used as a perfect biomaterial for repairing nerve injuries.     

壳聚糖膜的制备及其表面浸润性

采用流延法,通过调节壳聚糖溶液的质量分数制备表面结构不同的壳聚糖膜,并通过扫描电子显微镜和静态接触角测定仪对膜表面形貌及浸润性进行了研究。结果表明,壳聚糖溶液的质量分数是壳聚糖膜表面形貌的重要影响因素。在壳聚糖溶液的质量分数由2%增至8%条件下,所制备的壳聚糖膜的表面结构从有较强立体层次感的簇状凸起逐渐变得层次感降低,纹路密集,并出现很多紧密排列的小颗粒;膜表面的浸润性发生细微变化,在空气中均表现为既亲水又亲油的特性,而在水中油滴的表面接触角平均高达150°以上,即达到超疏油性。     

磁性壳聚糖微球的制备及其性能

用共沉淀法制备纳米级Fe3O4磁流体,并对其用油酸进行表面改性。采用化学交联法,在分散有磁流体的壳聚糖溶液中,加入适量的戊二醛交联剂,制得内核为磁性Fe3O4,外层包有壳聚糖的纳米级的磁性壳聚糖复合微球。考察了壳聚糖质量浓度、NaOH滴加量及搅拌速度等因素对磁性壳聚糖微球粒径、粒径分布以及形貌等对复合过程的影响,确定了制备磁性壳聚糖微球的最佳条件,并用电镜、红外光谱图、粒径分析仪等方法对磁性壳聚糖微球的形态和组成特性进行分析。最后得出平均粒径为348.5 nm,表面富含羟基、氨基和醇羟基等官能团,磁性明显、分散性良好的磁性壳聚糖微球。