京尼平交联壳聚糖支架的制备及性能研究

采用京尼平交联壳聚糖溶液制备壳聚糖水凝胶,冷冻干燥后制备壳聚糖细胞支架。研究制备工艺对壳聚糖支架性能的影响,结果表明,在中性环境下,交联制备得到的壳聚糖支架微观呈现均匀的多孔结构,孔隙率在90%以上;有较高的吸水率与蛋白吸附率(36.1mg/g);在37℃PBS环境中,体积溶胀率最低(11.0%)。力学测试表明其具有良好的回弹性,压缩至20%时,撤去应力,仍可恢复原始形貌,且压缩模量最高(81kPa)。MTT实验与SEM观察表明,PC12细胞在此支架中增殖较快。     

明胶/海藻酸钠(京尼平交联)互穿网络膜的制备与性能

为了提高海藻酸钠与明胶各自的性能,首先,以海藻酸钠和明胶为原料,以京尼平、CaCl2为交联剂,采用分步交联法制备了明胶/海藻酸钠互穿网络膜。然后,利用FTIR对明胶/海藻酸钠互穿网络结构进行了表征与分析,根据FTIR结果推测了互穿网络结构形成的机制。最后,探讨了京尼平的加入量和明胶与京尼平的质量比对互穿网络膜力学性能和交联度的影响,及海藻酸钠与明胶的质量比对互穿网络膜力学性能、断面形貌、热稳定性和吸水保水性能的影响。结果表明:当明胶与京尼平的质量比为200∶1、海藻酸钠与明胶的质量比为2∶1时,互穿网络膜具有最佳的力学性能、吸水保水性能和相容性;此外,互穿网络膜的力学性能也优于纯海藻酸钠膜与纯明胶膜的。明胶的加入提高了互穿网络膜在低温区的热稳定性,但降低了高温区的热稳定性。海藻酸钠与明胶之间可能以分子间作用力、氢键及离子键等相互作用,提高了二者各自的初始分解温度与最大热分解温度。研究解决了海藻酸钠与明胶力学性能差的问题,为拓展海藻酸钠在医用领域的应用提供参考。     

Microencapsulation of isoniazid in genipin-crosslinked gelatin-A–κ-carrageenan polyelectrolyte complex

Background: Microspheres of gelatin-A and κ-carrageenan were prepared by using genipin, a naturally occurring crosslinker, and sunflower oil as reaction media. Method: The variations in the size of the microspheres formed by varying the amount of surfactant (0.33–1.0 g/g of polymer), polymer (1.5–3.0 g), and crosslinker (0.2–0.8 mmol) were studied by scanning electron microscopy. The encapsulation of isoniazid was carried out by absorption. The isoniazid content in the prepared microspheres was determined. The release characteristic of isoniazid was also studied at pH values 1.2 and 7.4 by using UV-spectrophotometer. Results: Characterization of the isoniazid-loaded microspheres was carried out by using Fourier transform infrared spectrophotometry, differential scanning calorimetry, and X-ray diffractometery.     

京尼平与栲胶和铝盐的结合鞣研究

在前期对京尼平(genipin)与皮胶原反应性研究的基础上,进一步考察了其与缩合类的荆树皮栲胶、水解类的栗木栲胶和铝盐的结合鞣时,各种鞣剂的用量和使用先后顺序对皮粉湿热稳定性的影响。结果表明:(1)用栲胶预鞣、genipin复鞣的效果,要优于genipin预鞣、栲胶复鞣的效果;缩合类栲胶与genipin结合鞣的效果,要优于水解类栲胶;用铝盐预鞣、genipin复鞣的效果,要优于genipin预鞣、铝盐复鞣的效果。本研究为全植鞣工艺和铝预鞣白湿皮工艺提供了新的选择。     

热稳定酸性β - 葡萄糖苷酶的分离纯化及其酶学性质

耐酸性黑曲霉菌株Aspergillus niger L.的菌丝体破碎液依次经过乙醇沉淀、离子交换层析和凝胶过滤等步骤处理,获得电泳纯的β-葡萄糖苷酶,SDS-PAGE显示其分子质量为125.7kD。β-葡萄糖苷酶水解对硝基苯-β-D-吡喃葡萄糖苷的最适pH值为3.0～4.0,最适温度为70℃,表观米氏常数(Km)值为2.35mmol/L,表观kcat/Km值为2.99×104L/(mol ·s);水解京尼平苷、水杨苷的表观kcat/Km值分别是1.26×104、1.37×104L/(mol ·s);水解活性受Mn2+的显著激活和Fe2+、Zn2+、Cu2+等离子的微弱抑制。该酶活性在pH2.0～8.3保持稳定;酶在65℃时保温60min,残余酶活达到了85%,是一种热稳定酸性β-葡萄糖苷酶。     

Genipin交联明胶/溶菌酶缓释抗菌膜材料的微结构与性能研究

针对亲水明胶膜材料对抗菌剂缓释能力较差的问题,采用生物交联剂(genipin)调节膜材料微结构,制备出新型控释明胶/溶菌酶复合膜材料。系统研究了复合膜材料的力学性能、水汽阻隔性能、膨胀性和热性质等物理性能,并用AFM研究了膜材料的表面微结构,探讨了其结构-性能之间的关系。结果表明:genipin交联显著改善复合膜材料的力学性能,TS值从9.72 MPa逐渐增加至18.80 MPa;复合膜材料的膨胀度(swelling)随genipin浓度增加急剧下降,从1316%降至~200%;genipin交联提升复合膜材料的热稳定性。复合膜材的表面粗糙度依赖于genipin浓度,在低浓度段(0~1.0%),膜材料呈现平整表面微结构;高浓度(2.0%)时,膜表面出现不规则的突起,变得粗糙。适度的genipin交联有助于形成有序的三维网络结构,改善复合膜材料的物理性能;高浓度的genipin过度交联明胶基质,形成团聚状聚集物,及弱化明胶分子间相互作用,进而弱化膜材料的水汽阻隔能力。     

Chitosan-Based Materials Featuring Multiscale Anisotropy for Wider Tissue Engineering Applications

We designed graphene oxide composites with increased morphological and structural variability using fatty acid-coupled polysaccharide co-polymer as the continuous phase. The matrix was synthesized by N, O-acylation of chitosan with palmitic and lauric acid. The obtained co-polymer was crosslinked with genipin and composited with graphene oxide. FTIR spectra highlighted the modification and multi-components interaction. DLS, SEM, and contact angle tests demonstrated that the conjugation of hydrophobic molecules to chitosan increased surface roughness and hydrophilicity, since it triggered a core-shell macromolecular structuration. Nanoindentation revealed a notable durotaxis gradient due to chitosan/fatty acid self-organization and graphene sheet embedment. The composited building blocks with graphene oxide were more stable during in vitro enzymatic degradation tests and swelled less. In vitro viability, cytotoxicity, and inflammatory response tests yielded promising results, and the protein adsorption test demonstrated potential antifouling efficacy. The robust and stable substrates with heterogeneous architecture we developed show promise in biomedical applications.     

中草药有效成分的氚标记研究

本文就中草药有效成分的氚标记进行了研究,其中用二种不同的标记方法标记了三个中草药的有效成分：栀子苷元、乙酰阿卡宁和绿原酸等。经放射性TLC或HPLC分析,放化纯度都达到95％以上,比活度分别为：1.35GBq/mM、1.07GBq/mM和166.5 GBq/mM。     

大豆蛋白基复合水凝胶的制备及其体外释放

利用天然无毒的京尼平交联大豆蛋白(SB)和壳聚糖(CS)制备复合水凝胶(HD)控释载体,以茶碱(TP)作为药物模型,结合扫描电镜和核磁共振研究了复合凝胶的表观形态和结构,并对其在模拟胃肠液中的控释特性进行研究。结果表明:复合水凝胶中大豆蛋白和壳聚糖通过京尼平发生了明显的交联作用,并呈现紧密的网络结构。在pH1.2模拟胃液中,复合水凝胶的溶胀度和茶碱释放率较低,但在pH6.8模拟肠液中,却呈现较高的溶胀度和释放率。复合水凝胶在模拟胃肠液中120h内可实现对茶碱的可控释放。复合凝胶的释放特性不仅与SB/CS比例相关,而且还取决于添加的京尼平的含量。本实验结果说明了这种京尼平交联的复合凝胶较为适合用作药物在胃肠道中的定向运送载体。     

京尼平的分离纯化及高效液相色谱法测定

研究了用β-葡萄糖苷酶水解栀子苷制备京尼平及京尼平的分离纯化方法,同时还建立了京尼平的高效液相色谱检测法。静态吸附实验表明,HPD700对京尼平的吸附率可达96.50%,动态吸附及洗脱实验结果表明,上样流速以1.5BV/h为宜,采用无水乙醇对京尼平的洗脱率最高,达到94.32%。高效液相色谱法对京尼平的分析结果为:京尼平进样量在0.2~2.0μg范围内,峰面积与进样量呈良好的线性关系,京尼平的回归方程为Y=3.81×106X-19261,相关系数R2为0.9994,方法精密度为1.06%,回收率为98.5%~102.2%。结论:本实验制备的京尼平纯度可达98%以上,为制备高端栀子蓝色素创造了条件。