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.     

Adsorption behavior of cross-linked chitosan modified by graphene oxide for Cu（Ⅱ） removal

Cross-linked chitosan（CS）,cross-linked chitosan/graphene（CS/RGO10） and cross-linked chitosan/graphene oxide（CS/GO10） were prepared as adsorbents for Cu（Ⅱ）.The effects of pH,contact time,adsorbent dosage and initial concentration of Cu（Ⅱ） on the adsorbing abilities of CS,CS/RGO10 and CS/GO10 to Cu（Ⅱ） were investigated.The results demonstrate that the adsorption capacities of CS/GO10 and CS/RGO10 are greater than that of CS,especially at pH 5.0 and the adsorption capacities are 202.5,150 and 137.5 mg/g,respectively.Their behaviors obey the Freundlich isotherm model very well.Additionally,CS/GO10 has the shortest time to achieve adsorption equilibrium among them and can be used as a perspective adsorbent for Cu（Ⅱ）.     

β-环糊精改性壳聚糖微球的制备及其性能研究

采用反相悬浮法,通过环氧氯丙烷交联制备β-环糊精改性交联壳聚糖微球(CDS),用FTIR和SEM进行表征,研究其对甲基橙(MO)的吸附和缓释性能。考察吸附时间、溶液p H值、MO浓度、温度等因素对CDS微球吸附的影响,并与交联壳聚糖(CTS)微球进行比较。结果表明,在p H 4.0、交联CTS微球1h可达吸附平衡,而CDS 2 h达到平衡;吸附数据均符合Freundlich等温方程和二级动力学方程。     

铜离子印迹改性壳聚糖海绵的制备及应用研究

以醋酸铜为模板,甲醇、氯仿为溶剂,2-乙烯吡啶、丙烯酰胺为功能单体,乙二醇二甲基丙烯酸酯为交联剂,采用本体聚合法制备铜离子印迹聚合物;然后掺入到壳聚糖海绵的制备中,使壳聚糖海绵对铜离子的吸附率由27．1％提高到72．3％。制备的铜离子印迹改性壳聚糖海绵需要2d达到吸附平衡,吸附-解吸5次后,性能稳定。     

优质壳聚糖/壳寡糖的制备工艺及水溶性壳寡糖Fe(Ⅲ)配合物的合成

以皮皮虾壳作基本原料,分别采用稀盐酸、稀碱溶液浸泡,除去虾壳中的钙质等无机质和蛋白等有机成分,以浓碱脱除甲壳素上的乙酰基,制得壳聚糖.再以其为原料,采用H2O2氧化降解法得到水溶性壳寡糖.将所制水溶性壳寡糖加入到氯化铁溶液中,设定各项条件,使二者进行配位反应.经系列实验证实,得出制备高脱乙酰度壳聚糖最适宜条件为:温度85℃,时间9 h,NaOH质量分数45%,料液比1∶300.所得产品脱乙酰度为89.6%,收率(壳聚糖/甲壳素)为73.1%,其他各项指标也均为优良级.制备水溶性壳寡糖最适宜条件为:温度65℃,时间6 h,醋酸质量分数4.0%,H2O2质量分数4.0%,产品平均粘均分子质量为2.9 ku,外观为淡黄色粉末,溶解性能优良.通过对FT-IR和UV谱图的分析,证实了水溶性壳寡糖Fe(Ⅲ)配合物的生成.     

水力空化联合H2O2降解壳聚糖的研究

利用水力空化装置对壳聚糖溶液进行了降解实验。分析了壳聚糖浓度、入口压力、p H值、温度、H2O2浓度等不同因素对壳聚糖溶液降解的影响。结果表明:水力空化对壳聚糖的降解程度随壳聚糖浓度的增加而减小,随着入口压力及水温的增加而增大;在一定条件下,水力空化对壳聚糖的降解存在着一个最佳的p H值;水力空化联合H2O2强化处理大大增强了降解的效果。该方法既能减少氧化剂的投放,也能提高降解的效率。     

马铃薯涂膜-微波复合膨化工艺的研究

在玉米微波膨化原理的基础上,建立了涂膜-微波复合膨化工艺,并以马铃薯块为原料,制备了类似于玉米爆米花、可用微波炉进行膨化的食品.理论上,将阻水性好、可食用的壳聚糖膜涂覆于马铃薯块表面,利用微波加热后,马铃薯块内部的水分会蒸发成水蒸气.而水蒸气受到壳聚糖膜的阻隔,无法散失.当水蒸气的压力越积越大,马铃薯块会爆开,得到微波膨化食品.研究结果表明,用2%的壳聚糖溶液涂布于马铃薯块(体积为2 cm×2 cm×2 cm)表面,于80℃干燥13.5 h,然后微波膨化60 s后,产品的膨化效果最佳,膨化率为270%±41%.     

天然高聚物基手术缝合线的研究现状北大核心CSCD

医用手术缝合线种类丰富,其制备原料可分为天然材料、合成材料及金属材料等,其中天然高聚物基手术缝合线以其优异的生物相容性、低免疫原性等特性在市场上占据主体地位,但仍存在机械性能较差、降解速率难以调控等问题。为了改善天然高聚物基缝合线的性能,促进新型缝合线的研究发展,并使其进一步满足医用领域的应用需求,本文综述了蚕丝基、胶原基、甲壳素基三类天然高聚物基缝合线的研究现状,比较了三者在实际应用中的优缺点,并分析了三者存在的性能缺陷及改进方向,以期为天然高聚物基手术缝合线的研究发展提供参考。     

Nano-Au/复合壳聚糖@纳米碳修饰金电极检测亚硝酸盐

该文介绍了以复合壳聚糖@纳米碳为基底固定纳米金,利用具有催化性的纳米碳及纳米金作为识别元素检测亚硝酸盐,从而制备了无生物物质标记且无电子媒介体的亚硝酸盐传感器。该修饰电极在亚硝酸盐浓度为8.0×10-6~2.0×10-4mol/L范围内有线性响应,线性相关系数r=0.9956。实验结果表明,该传感器具有制备简单、灵敏度高、稳定性好、线性范围宽等优点。     

壳聚糖膜在重金属处理中的应用研究

以壳聚糖为原料,制备了壳聚糖(CS)超滤膜、邻苯二甲酸二丁酯(DBP-C)壳聚糖多孔膜、壳聚糖/聚乙烯醇(CS/PVA)共混膜三种膜.通过综合运用原子吸收和红外光谱等技术研究交联剂的种类、剂量,对交联壳聚糖膜的物理化学性质与结构的关系及其对重金属离子Cd~(2+)、Pb~(2+)的吸附的影响,添加戊二醛、环氧氯丙烷交联剂对交联壳聚糖微球的影响及其对重金属离子Cd~(2+)、Pb~(2+)的吸附效果.结果表明,交联剂剂量和种类对有效去除重金属离子十分关键,红外光谱研究显示壳聚糖分子中带有的大量活性基团(-NH_2/-OH)与重金属离子配位形成金属螯合物去除了重金属离子;扫描电子显微镜结果表明交联壳聚糖膜在吸附重金属离子前后发生了显著变化,由光滑转变成粗糙.