丝素膜上药物渗透量对溶液PH值的响应

蚕丝丝素蛋白膜是一种具有弱碱性和弱酸性的两性荷电膜。因此在丝素膜－水溶液体系中，水溶液ｐＨ值变化会影响丝素膜上溶质的渗透速度和渗透量。丝素膜的等电点ｐＨ≈４．５。丝素膜上药物渗透实验的结果表明：在ｐＨ＝３．０～９．０的范围内，当溶液的ｐＨ＜４．５时，丝素膜带正电，正离子苄三甲氯化铵的渗透系数下降；当溶液的ｐＨ＞４．５时，丝素膜带负电，负离子酚磺酸钠的渗透系数明显下降。中性分子间苯二酚在丝素膜上的透过不受外部溶液ｐＨ值变化的影响。当溶液的ｐＨ＞８或ｐＨ＞４．５时，离子化的药物５－氟尿嘧啶或维生素Ｃ的渗透系数明显变小，这是因为两者分别在ｐＨ＝８（ｐＫａ＝８．０）和ｐＨ＝４．５（ｐＫａ＝４．２５）以上变成带电离子。这表明离子化药物在蚕丝丝素膜上的渗透速度和渗透量对溶液ｐＨ值变化有较好的响应特性。     

醋酸纤维素膜及其混合膜渗透气化性能的研究——稀溶液粘度斜率系数的依赖性

研究了醋酸纤维素（CA），乙烯－醋酸乙烯共聚物（EVA），聚乙烯醇缩丁醛（PVB）和聚醋酸乙烯酯（PVAc) 4种高聚物在不同溶剂中的稀溶液粘性行为。同时，从各相应的溶剂中制备了CA均一膜，CA－PVB和CA－PVAc共混膜以及CA－EVA复合膜，并测定了各种膜对甲醇（MeOH），甲基叔丁基醚（MTBE）混合物的渗透气化性能。结果表明，各种膜的渗透通量（J）与其稀溶液粘度斜率系数（b)成反比，即呈现随b值增大J值下降现象。     

单链脱氧核糖核酸探针在羧基聚苯乙烯小珠表面的微阵列条件及固—液杂交特

优化在１－乙基－３－（３－二甲基氨丙基）－碳化二亚胺（ＥＤＣ）存在下,５′－ＮＨ２单末端和５′－ＴＲ／３′－ＮＨ２双末端修饰单链脱氧核糖核酸（ＤＮＡ）探针在１０μｍ羧基聚苯乙烯小珠表面进行微阵列的条件,研究５′－ＮＨ２单末端修饰ＤＮＡ探针与其碱基互补充阢进行的固－液杂交特性。结果表明,在ＰＨ４．６－５．６,ＥＤＣ浓度为０．５－０．７ｇ／Ｌ时,ＤＮＡ探针在小珠表面具有最大的微阵列能力。微阵列在小珠表面的５′－ＨＮ２单末端修饰ＤＮＡ探针,与期 碱基互补序列的杂交反应遵守二级反应动力学,杂交优化条件除取决于溶液介质的ＰＨ值,离子强度和碱基互补序列 溶液介质中的浓度外,还取决于环境温度和杂交时间。测定了２５℃下微阵列在小珠表面的２０－ｍｅｒＤＮＡ探针与其溶液中互补序列的杂交反应常数。     

SYNTHESIS AND ANTI－HUMAN IMMUNODEFICIENCY VIRUS－1（HIV－1） ACTIVITY OF 9－（2－PHOSPHONYLMETHOXYETHYL）ADENINE （1）AND ITS REGIOISOMER 3－（2－PHOSPHONYLMETHOXYETHYL）ADENINE（2）

ＳＹＮＴＨＥＳＩＳＡＮＤＡＮＴＩ－ＨＵＭＡＮＩＭＭＵＮＯＤＥＦＩＣＩＥＮＣＹＶＩＲＵＳ－１（ＨＩＶ－１）ＡＣＴＩＶＩＴＹＯＦ９－（２－ＰＨＯＳＰＨＯＮＹＬＭＥＴＨＯＸＹＥＴＨＹＬ）ＡＤＥＮＩＮＥ（１）ＡＮＤＩＴＳＲＥＧＩＯＩＳＯＭＥＲ３－（２－ＰＨＯ...     

SYNTHESTS OF 5-SUBSTITUTED PHENYLAMINO 6-PHENY-1. 2. 4-TRIAINE-3-ONES

ＳＹＮＴＨＥＳＴＳ　ＯＦ　５－ＳＵＢＳＴＩＴＵＴＥＤ　ＰＨＥＮＹＬＡＭＩＮＯ　６－ＰＨＥＮＹ－１．２．４－ＴＲＩＡＩＮＥ－３－ＯＮＥＳ￥ＺｈｏｎｇＥＬＵ；ＷｅｎＱｉｎＺＨＥＮＧ；ＲｕｎＳｈｅｎｇＺＥＮＧ；ＪｉａｎＰｉｎＺＨＯＵ；ＫｅＱｉａｎＣＨＥＮ（...     

SYNTHESIS OF DI－（2＇－DEOXY－2＇－FLUORO）PYRIMIDINENUCLEOSIDE PHOSPHATES AND PHOSPHOROTIOATES

ＳＹＮＴＨＥＳＩＳＯＦＤＩ－（２＇－ＤＥＯＸＹ－２＇－ＦＬＵＯＲＯ）ＰＹＲＩＭＩＤＩＮＥＮＵＣＬＥＯＳＩＤＥＰＨＯＳＰＨＡＴＥＳＡＮＤＰＨＯＳＰＨＯＲＯＴＩＯＡＴＥＳＺｈｅｎｇＦｕＷＡＮＧ；ＹｉＢｉｎｇＺＨＡＮＧ；ＹａｏＱｕａｎＣＨＥＮ（Ｌａｂｏｒａ...     

INTERMOLECULAR PHOSPHORYL GROUP TRANSFER FROM N－（O，O－DⅡSOPROPYL）PHOSPHORYL ASPARAGINE TO TRYPSIN

ＩＮＴＥＲＭＯＬＥＣＵＬＡＲＰＨＯＳＰＨＯＲＹＬＧＲＯＵＰＴＲＡＮＳＦＥＲＦＲＯＭＮ－（Ｏ，Ｏ－ＤⅡＳＯＰＲＯＰＹＬ）ＰＨＯＳＰＨＯＲＹＬＡＳＰＡＲＡＧＩＮＥＴＯＴＲＹＰＳＩＮ￥ＷｅｉＨｕａＺＨＯＵ；ＹｕＦｅｎＺＨＡＯ（Ｂｉｏｏｒｇａｎｉｃｐｈｏｓｐ...     

壳聚糖-聚乙烯基恶唑啉半互穿聚合物网络(semi-IPN)膜对pH的刺激响应性

研究了壳聚糖－聚乙烯基恶唑啉半互穿聚合物网络膜对ＰＨ值的敏感性,发现该膜在ＰＨ〈６时溶胀度迅速增加,在ＰＨ＝３．２时达到最大值;膜在不同ＰＨ值溶液中可交替溶胀收缩,且这种溶胀－收缩行为重复可逆。     

纳米TiO2/丝素复合膜的制备

探讨了纳米TiO2在丝素溶液中的分散条件,在此基础上制备了纳米TiO2/丝素复合膜,并用原子力显微镜(AFM)和扫描电子能谱(EDS)对复合膜进行了表征。实验结果表明,制膜方法较为合理。当以有机物A为分散剂,纳米TiO2含量为1/1000时,其以粒径50 nm左右均匀地分散于复合膜中。     

电沉积条件对非晶态Fe—Mo合金结构及表面性质的影响

利用ＸＲＤ、ＳＥＭ和ＸＰＳ等手段研究了电解液中ｘ（Ｍｏ）、（Ｍｏ在Ｍｏ＋Ｆｅ中的摩尔分数）、电流密度及温度变化对电沉积非晶态Ｆｅ－Ｍｏ合金的结构和表面性质的影响。溶液中主要含有ＦｅＳＯ４、Ｎａ２ＭｏＯ４、Ｈ３Ｃｉｔ，ＰＨ值３－５，当ｘ（Ｍｏ）大于５０％，电流密度高于２５ｍＡ／ｃｍ＾２，温度低于４０℃时有利于形成非晶态结构，合金沉积层的表面呈粒状且有微裂纹，表面的化学性质很活泼，容易形成含低价Ｍｏ的     

丝素膜修饰电极pH电荷选择效应的研究

研究了丝素膜的带电特性,其等电点在pH4.5附近,利用丝系膜在等电点前后的两性荷电特性和电荷之间的静电作用,研制了丝素膜修饰石墨电极,多巴胺在膜中的表观扩散系数为2.65×10^-7cm^2/s,其电极反应异相电子转移速率常数为8.9×10^-6cm/s,电极用于神经递质类化合物体系的测定中,验证了此修饰电极的pH电荷选择效应。     

用丝素膜制备的纳米CdS及其光催化活性研究

根据蚕丝丝素蛋白等电点约4.5的特性,以CdCl_2·2.5H_2O和CH_3CSNH_2为原料,将CdCl_2用明胶包覆后置于定制的丝素膜反应器中,在pH=6条件下制得纳米 CdS。经 UV、AFM表征,CdS的平均粒径为 5～10 nm,其对活性染料 KD-8B有较好的光催化降解活性。     

Entrapment of both glucose oxidase and peroxidase in regenerated silk fibroin membrane

Two enzmyes, glucose oxidase and peroxidase, were for the first time simultaneously immobilized in regenerated silk fibroin membrane. The structure and morphology of the regenerated silk fibroin membrane containing both glucose oxidase and peroxidase were investigated with IR spectra and SEM. The bienzymes do not change the structures of the regenerated silk fibroin in the membrane, which has an islands-sea structure. For the first time, an amperometric methylene green mediating sensor for glucose based on co-immobilization of both glucose oxidase and peroxidase in regenerated silk fibroin was constructed. Cyclic voltammetry and amperometry were used to test the suitability of methylene green shuttling electrons between peroxidase and the glassy carbon electrode. The bienzyme-based system offers fast response and high sensitivity of the sensor to glucose. The effects of pH, temperature, and the concentration of the mediator on the response current were evaluated, and the dependence of the Michaelis-Menten constant K(m)(app) on the concentration of the mediator was investigated.     

Entrapment of both glucose oxidase and peroxidase in regenerated silk fibroin membrane

Two enzmyes, glucose oxidase and peroxidase, were for the first time simultaneously immobilized in regenerated silk fibroin membrane. The structure and morphology of the regenerated silk fibroin membrane containing both glucose oxidase and peroxidase were investigated with IR spectra and SEM. The bienzymes do not change the structures of the regenerated silk fibroin in the membrane, which has an islands-sea structure. For the first time, an amperometric methylene green mediating sensor for glucose based on co-immobilization of both glucose oxidase and peroxidase in regenerated silk fibroin was constructed. Cyclic voltammetry and amperometry were used to test the suitability of methylene green shuttling electrons between peroxidase and the glassy carbon electrode. The bienzyme-based system offers fast response and high sensitivity of the sensor to glucose. The effects of pH, temperature, and the concentration of the mediator on the response current were evaluated, and the dependence of the Michaelis-Menten constant K_m^app on the concentration of the mediator was investigated.     

丝素纳米颗粒的制备及应用于L-天冬酰胺酶的固定化

丝素蛋白纤维溶于高浓度中性盐溴化锂溶液或氯化钙-乙醇-水三元溶剂中, 经过透析和纯化可以制成3种液态丝素. SDS-PAGE分析结果表明, 其分子量分布范围明显不同. 应用能与水混溶的有机溶剂如丙酮等可将这种丝素制成丝素纳米颗粒, 用SEM观察到丝素纳米颗粒粒径分布范围为50~120 nm. 以戊二醛为交联剂, 将治疗急性淋巴性白血病常用酶制剂L-天冬酰胺酶共价结合在丝素纳米颗粒上. 酶活性分析结果表明, 由肽链断裂较少的丝素制备的纳米颗粒更适合于酶的生物结合. 酶动力学研究结果表明, 这种固定化酶活性回收率为44%, 热稳定性较游离酶有明显提高, 最适pH值范围加宽为6.0~8.0, 最适反应温度提高10 ℃; 抗胰蛋白酶水解能力明显增强. 结果表明, 丝素纳米颗粒与丝素蛋白膜一样, 是一种酶固定化的良好载体, 在药物缓释系统方面具有潜在的研究和开发价值.     

Preparation and Characterization of Natural Silk Fibroin Hydrogel for Protein Drug Delivery

In recent years, hydrogels have been widely used as drug carriers, especially in the area of protein delivery. The natural silk fibroin produced from cocoons of the Bombyx mori silkworm possesses excellent biocompatibility, significant bioactivity, and biodegradability. Therefore, silk fibroin-based hydrogels are arousing widespread interest in biomedical research. In this study, a process for extracting natural silk fibroin from raw silk textile yarns was established, and three aqueous solutions of silk fibroin with different molecular weight distributions were successfully prepared by controlling the degumming time. Silk fibroin was dispersed in the aqueous solution as “spherical” aggregate particles, and the smaller particles continuously accumulated into large particles. Finally, a silk fibroin hydrogel network was formed. A rheological analysis showed that as the concentration of the silk fibroin hydrogel increased its storage modulus increased significantly. The degradation behavior of silk fibroin hydrogel in different media verified its excellent stability, and the prepared silk fibroin hydrogel had good biocompatibility and an excellent drug-loading capacity. After the protein model drug BSA was loaded, the cumulative drug release within 12 h reached 80%. We hope that these investigations will promote the potential utilities of silk fibroin hydrogels in clinical medicine.     

Determination of molecular weight of silk fibroin by non-gel sieving capillary electrophoresis

A simple non-gel sieving capillary electrophoresis (NGSCE) method was established to determine the MW of silk fibroin using CE. The background electrolyte with a pH of 8.8 was based on three components: polyethylene glycol, tris(hydroxymethyl)aminomethane, and sodium dodecyl sulfate (SDS). NGSCE showed a good linear relationship with satisfactory reproducibility between the migration time and the MW of standard proteins. It was found that the regenerated silk fibroin had an MW around 83 kDa with a wide MW distribution (MWD). This absolute value is lower than the result obtained from SDS-polyacrylamide gel electrophoresis due to the different principles of the methods, but their similar MWD shapes indicated that NGSCE could be a feasible, highly sensitive, rapid method for determination of the MW of silk fibroin.     

Silk fibroin solution properties related to assembly and structure

The impact of physiological factors on silk fibroin solution properties was studied. Specifically, the impact of fibroin concentration, protein purity, cation type and concentration, and pH on aqueous solution viscosity, shear behavior, and surface tension were assessed in the context of silk protein assembly. The results demonstrate that in vitro results could be correlated to in vivo processing events during silk spinning. Rheological properties with reference to the amphiphilic block structure of the protein are described, pH dependency of shear response was quantitatively correlated to the predicted pI values of the fibroin protein, and cooperativity among environmental factors such as pH and salts was identified. Stabilization of silk fibroin solution states by calcium was identified as a mode to control shear sensitivity of the fibroin solution. The cooperativities identified suggest tight control of fibroin aqueous solution rheological properties to gain a window of protection against premature crystallization of the fibroin during processing, assuring safe storage, transport, and finally successful fiber spinning.