部分氧化海藻酸钠的制备与性能

部分氧化海藻酸钠的制备与性能;海藻酸钠;氧化;降解;水凝胶     

A Fast Made Disposable Glucose Biosensor Incorporating the Oxidase and a Ferrocene in an Alginate Gel

Abstract

A simple procedure is described for co-immobilization of glucose oxidase and dimethylaminomethylferrocene in a sodium alginate gel on the surface of pyrolytic graphite electrode. The film is electrochemically active and the peak current is a function of D-glucose concentration with the apparent Michaelis-Menten constant K_m = (1.2±0.3) × 10^?2 M. The optimal concentration range for biosensoric applications in 0.001–0.010 M.

     

海带多糖对铅中毒大鼠生殖系统的影响

通过建立大鼠铅中毒模型,研究海带多糖对铅中毒大鼠生殖系统的影响。大鼠48只,雌雄各半,随机分为正常对照组（正常饮食30d）、模型组（自由饮用0.3%醋酸铅水溶液30d）、青霉胺组（自由饮用0.3%醋酸铅水溶液30d＋按90mg.kg-1体重ip青霉胺21d）、海带多糖高、中、低剂量组（自由饮用0.3%醋酸铅水溶液30d＋200mg.kg-1、100mg.kg-1,50mg.kg-1ig海带多糖）。实验结束处死大鼠,取血测定血铅,取睾丸、附睾、卵巢、子宫等生殖器官,称重并计算脏器指数,观察雄鼠精子数、死亡精子数、畸形精子数,测定促卵泡成熟激素（FSH）、生殖激素睾酮（T）、促黄体生成激素（LH）的变化。结果表明,海带多糖能降低铅中毒后大鼠的血铅,附睾、睾丸指数降低情况得到改善（P〈0.05）,精子的畸形率、死亡率有所降低（P〈0.05）;精子活动率、密度有所增高（P〈0.05）;T、FSH水平的降低得到改善（P〈0.05）,而对LH的水平影响不大（P〉0.05）。这说明海带多糖对铅中毒大鼠的生殖系统有保护作用,有望开发成天然低毒的铅中毒保护药。     

Development and rheological investigation of novel alginate/N‐succinylchitosan hydrogels

In the present article alginate hydrogels and novel hydrogels based on blends of alginate/N‐succinylchitosan have been realized in water solution at neutral conditions. The gels have been obtained by crosslinking via the internal setting method using calcium carbonate (CaCO₃) as calcium ions source. A rheological investigation of both the plain alginate and the alginate/N‐succinylchitosan blend hydrogels has been performed by means of oscillatory dynamic measurements. The effect of the inclusion of different amounts of CaCO₃ on the critical deformation (γ_c) characterizing the limit of the linear viscoelastic regime has been studied for the plain alginate gels. The frequency response in small amplitude oscillatory experiments of the plain alginate gels has been investigated in terms of the storage (G′) and loss (G″) modulus behavior. The dynamic data have been interpreted in terms of the Friedrich and Heymann model. The inclusion of the N‐succinylchitosan, in the range 10–50% w/w, had no effect on the γ_c values. On the contrary, when the 10% w/w of the N‐succinylchitosan is added to the plain alginate gels, a significant increase in the storage modulus values is recorded for all the systems analyzed. The gelation kinetics has been investigated and the results indicate that the kinetics process can be accelerated increasing the percentage of Ca⁺² ions and/or including the N‐succinylchitosan in the plain alginate systems. Finally, the morphological analysis of scaffolds obtained from the hydrogels through freeze‐drying revealed an interconnected porous structure. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1167–1182, 2008     

氧化还原蛋白质在海藻酸钠溶液中的直接电子转移

将血红蛋白（Hb）、葡萄糖氧化酶（GOD）溶解在海藻酸钠（SA）溶液中，GOD和Hb均能在裸的玻碳电极（GCE）上发生有效和稳定的直接电子转移反应。实验结果表明，在海藻酸钠溶液中，GOD（pH=5．0）和Hb（pH=7．0）分别在裸的GCE上有一对很好的几乎对称的氧化还原峰；其式量电位（E°′）分别为一0．406V和～0．413（vs．Ag／AgCl），且不随扫速而变。GOD和Hb分别在裸的GCE表面直接电子转移的表观速率常数ks分别是（1．46±0．62）s^-1和（1．36±0．50）s^-1，在298K，其吉布斯自由能（△G）分别是79．35kJ·mol^-1和37．49kJ·mol^-1对葡萄糖和H2O2的电催化实验表明，海藻酸钠溶液形成了GCE与GOD或Hb之间实现“软接触”的生物环境，保持了Hb和GOD的生物和电化学活性。     

Controlled Release of an Antihypertensive Drug through Interpenetrating Polymer Network Hydrogel Tablets of Tamarind Seed Polysaccharide and Sodium Alginate

The application of interpenetrating polymer network (IPN) hydrogel tablets of tamarind seed polysaccharide and sodium alginate for controlled release of a water-soluble antihypertensive drug, propranolol HCl (PPL), was investigated. The IPN tablets loaded with PPL or PPL–resin complex (resinate) were prepared by a wet granulation/covalent cross-linking method. Fourier Transform Infrared Spectroscopic confirmed the cross-linking reaction and IPN formation, while X-ray Diffraction and Scanning Electron Microscopy studies confirmed the amorphous dispersion of the drug within the IPN tablets. The plain drug PPL showed complete release within 1 h, while drug release from the resinate was prolonged for 2.5 h and the IPN matrices showed drug release up to 24 h. The drug release rate from the IPN matrices was affected by polymer concentration and cross-linking time; the higher the cross-linking time, the slower was the drug release. The drug release mechanism was found to be of a non-Fickian type.     

海藻酸钠溶液-Co~(2+)体系溶胶-凝胶相转移的光谱学研究

以１３Ｃ－ＮＭＲ、ＩＲ、ＵＶ和Ｒａｍａｎ光谱学方法研究了海藻酸钠溶液－Ｃｏ２＋体系的溶胶—凝胶相转移过程，结合体系的光谱学分析对体系相转移过程中海藻酸分子链与Ｃｏ２＋的定位方式、分子链的结构与构型变化以及与之紧密相关的溶剂行为进行了定性的剖析．结果表明，体系内部Ｃｏ２＋对海藻酸分子链的交联作用主要发生在羧基官能团上，并存在着自由Ｃｏ２＋与交联Ｃｏ２＋间的迅速的化学交换过程，而溶质溶剂间存在的强烈的相互作用是体系凝胶化的重要条件．     

Disposable Immunosensor for Escherichia Coli O157:H7 Based on a Multi-Walled Carbon Nanotube-Sodium Alginate Nanocomposite Film Modified Screen-Printed Carbon Electrode

A disposable immunosensor for the detection of Escherichia coli O157:H7 based on a multiwalled carbon nanotube–sodium alginate nanocomposite film was constructed. The nanocomposite was placed on a screen-printed carbon electrode, and horseradish peroxidase-labeled antibodies were immobilized to E. coli O157:H7 on the modified electrode to construct the immunosensor. The modification procedure was characterized by atomic force microscopy and cyclic voltammetry. Under optimal conditions, the proposed immunosensor exhibited good electrochemical sensitivity to E. coli O157:H7 in a concentration range of 10³–10¹⁰ cfu/mL, with a relatively low detection limit of 2.94 × 10² cfu/mL (S/N = 3). This immunosensor exhibited satisfactory specificity, reproducibility, stability, and accuracy, making it a potential alternative tool for early assessment of E. coli O157:H7.     

假单胞交替菌BYS-2产褐藻胶裂解酶条件研究

以褐藻酸钠作为初筛培养基的唯一碳源,从鲍鱼养殖水样中分离获得一株产褐藻胶裂解酶的假单胞交替菌BYS-2。对该菌株进行产酶条件研究,获得最适产酶配方(w/v)为：褐藻酸钠0.1%,葡萄糖0.05%,酵母膏1%,黄豆饼粉0.3%,(NH4)2HPO4 0.3%,初始培养基pH8.0;最佳产酶条件为：接种量2%(v/v),装液量50mL/250mL,发酵温度20℃,摇床转速200 r/min,在此条件下发酵24h酶活力可达5.29U/mL,比优化前(1.57 U/mL)提高2.37倍。     

Transport selectivity of carbonate and chloride ions througha strongly alkaline anion-exchange membrane before and after its modification with sodium alginate

The transport selectivity of carbonate ions relative to chloride ions \(\left( {P_{Cl^ - }^{CO_3^{2 - } } } \right)\) through an anion-exchange membrane during electrodialysis is investigated before and after the membrane was modified by the electrolytic precipitation of sodium alginate on its surface, as well as by pretreating the membrane in a solution of sodium alginate. It is established that the experimental value of \(P_{Cl^ - }^{CO_3^{2 - } } \) is appreciably smaller than the calculated value for the unmodified membrane at low values of current density. At large currents the calculated value of \(P_{Cl^ - }^{CO_3^{2 - } } \) is 0.83, and the experimental value is 0.64. During electrodialysis of the working solution, which contains sodium alginate at a concentration of 1–2 g l^?1, \(P_{Cl^ - }^{CO_3^{2 - } } \) decreases by 2–3 times in the current-density range 0.25–1 A dm^?2. Pretreatment of the membrane in a solution of sodium alginate having a concentration of 10 g l^?1 for 72 h decreases \(P_{Cl^ - }^{CO_3^{2 - } } \) from 0.50 (unmodified membrane) to 0.35.