海藻酸钙软骨材料的凝胶化过程研究

以软骨材料的研究和应用为背景,在分析了海藻酸钙作为软骨材料的研究现状和应用前景的基础上,制备了海藻酸钙凝胶微球软膏填充材料,考察了材料的粒径、含水量、凝胶速率、力学性能和溶胀性能,了解了材料组分、配比对材料性能的影响;通过对凝胶微球表面形貌的观察察,了解了凝胶微球表面的特点,通过红外光谱的分析,了解了凝胶反应对凝胶材料谱峰的影响.     

丙烯腈接枝改性海藻酸钙水凝胶中水杨酸的释放行为

将海藻酸钙水凝胶与丙烯腈单体进行不同程度的接枝共聚改性,再由FTIR加以分析,并测定包埋了水杨酸模拟药物的改性海藻酸钙水凝胶在不同介质中的药物释放量。实验表明,改性海藻酸钙水凝胶的药物释放量既与介质有关,也取决于接枝率的大小。     

紫薯花色苷果胶/海藻酸钙复合凝胶球的制备及性能研究

采用离子凝胶法制备了荷载紫薯花色苷的果胶/海藻酸钙凝胶球,以弹性、硬度、紫薯花色苷包封率为评价指标,探讨氯化钙浓度、果胶与海藻酸钠比例、胶凝时间对指标的影响。结果表明,随着氯化钙浓度、果胶添加量的增大及胶凝时间延长,凝胶球的硬度和包封率增大。当果胶/海藻酸钠比为7∶1,氯化钙浓度为9%,胶凝时间为5 min时,此时制备的凝胶球硬度最大,弹性适度,包封率最大。SEM扫描电镜显示,凝胶球具有明显的核壳结构。溶胀和模拟胃肠液实验显示,凝胶球在碱性和肠液中易溶胀,在结肠中释放最大,达到54.8%。     

固定化葡萄糖氧化酶的研究

用对苯二酚和甲醛在酸性条件下制得新一类凝胶，此凝胶可作为载体对多种酶及蛋白质给予固定。本文研究了对葡萄糖氧化酶的固定，在最佳条件下固定的固化酶，其酶活可达760U／g（干载体）；同时研究了固化酶的热稳定性，结果表明固定化葡萄糖氧化酶具有较好的稳定性及应用前景。     

纳米纤维/海藻酸钙抗菌复合水凝胶的制备与表征

海藻酸钙水凝胶敷料作为一种"湿疗法"产品广泛用于伤口护理领域,但其无抗菌性,且缺乏细胞黏附的位点。通过将海藻酸盐和纳米氧化细菌纤维素(TOBC)共混,使用浸渍富集法负载抗菌剂聚六亚甲基双胍(PHMB)制备出一种多功能复合水凝胶,并使用场发射扫描电镜、酶标仪、激光共聚焦显微镜对复合水凝胶的结构和性能进行表征。结果表明:复合水凝胶为透明状,表面存在大量的纳米纤维,生物活性得到提高。使用0.001%PHMB溶液处理后,复合水凝胶对于大肠埃希菌和金黄葡萄球菌均具有良好抗菌效果,同时兼具优异的生物相容性。     

海藻酸钙纤维非织造布的水凝胶化改性及机理

采用HCl水溶液和NaOH乙醇溶液,通过两步法对海藻酸钙纤维针刺非织造布进行水凝胶化改性,研究改性工艺对样品结构与性能的影响,并探究改性机理。结果表明,HCl水溶液的最佳浓度为0.05%～0.1%（质量）,NaOH乙醇溶液的最佳浓度为0.008%～0.016%（质量）,此时改性样品的遇水凝胶性能最佳,吸水量提高了1.45倍,但厚度、断裂强力等物理性能变化不大。HCl处理破坏了纤维的“egg-box”结构和结晶结构,降低了其结晶度和Ca²⁺含量,但在纤维分子间形成了酯键。NaOH处理使新形成的酯键水解,削弱纤维分子间的作用力,使得大量水分子扩散进入到纤维大分子之间,并通过氢键作用形成三维网络结构,从而转变成凝胶体。     

块状木质素磺酸钠/海藻酸钙复合气凝胶的制备、表征及性能

以木质素磺酸钠和海藻酸钠为原料,采用溶液共混法和真空冷冻干燥制备块状木质素磺酸钠/海藻酸钙复合气凝胶,通过扫描电子显微镜(SEM)、傅立叶变换红外光谱仪(FTIR)、X-射线衍射仪(XRD)、热重分析仪(TG)对其结构进行表征,并分析了其力学性能和吸附性能。结果表明,所制备的气凝胶表面呈层状包裹结构,存在尺寸不一的孔洞;木质素磺酸钠和海藻酸钠主要通过氢键和范德华力结合在一起;木质素磺酸钠的引入提高了海藻酸钙气凝胶的结晶度和热稳定性;气凝胶的压缩强度随木质素磺酸钠含量的增加逐渐减弱;气凝胶对亚甲基蓝和Pb~(2+)均表现出较强的吸附性能,其中气凝胶SA-75对亚甲基蓝的吸附率达到83.65%,气凝胶SA-50对Pb~(2+)的吸附率达到79.89%。     

海藻酸钙基杂化水凝胶膜的制备及性能

针对纯海藻酸钙水凝胶膜力学性能差、电解质溶液中易溶胀的问题,以羧化二氧化钛(Ti O2-COOH)为增强剂、海藻酸钠为成膜基材、钙离子为交联剂制备无机/有机杂化水凝胶过滤膜。通过红外光谱和扫描电镜表征羧化二氧化钛的化学结构和形貌,研究杂化膜的孔径分布、力学性能、溶胀性能以及染料截留性能。结果表明,羧化二氧化钛均匀分散在膜表面,添加羧化二氧化钛后,膜的力学性能和抗溶胀性显著提高,在0. 1 MPa压力下对直接黑38和维多利亚蓝b的截留率分别达96. 6%和95. 3%,通量在13. 9 L/(m2·h)以上。     

海藻酸钙微胶囊的制备

研究了海藻酸钙微胶囊的制备条件和影响因素。试验结果表明 :海藻酸钠浓度不宜超过 3.0 % ,Ca Cl2的浓度为 1.0 %～ 4 .0 % ,适宜转速为 30 0 r· min- 1 ,下滴速率可控制在 6 0～ 90滴· m in- 1 ,成型的微胶囊浸泡在蒸馏水中存放 30 d后变化不大     

甲壳素/海藻酸钙凝胶球的制备及其对Cu2+的吸附性能研究

采用机械活化法协同FeCl₃预处理甲壳素,然后将其溶解在NaOH/尿素溶液中,再与海藻酸钠溶液共混,逐滴加入到CaCl₂溶液中,制备出甲壳素/海藻酸钙凝胶球(CCAGB),作为吸附剂吸附Cu²⁺。利用FT-IR、XPS和SEM对凝胶球进行表征,探究溶液初始pH、质量浓度等对吸附性能的影响。结果表明,甲壳素和海藻酸钠最佳质量比为1∶5时,CCAGB的结构稳定且具有蜂窝状的孔结构;在温度为30℃、转速为150 r/min、pH为6.0和吸附平衡时间为10 h的条件下,CCAGB对Cu²⁺的最大吸附量为169.49 mg/g,其吸附过程符合准二级动力学模型和Langmuir吸附等温模型。     

含超细Au颗粒的乳酸氧化酶和葡萄糖氧化酶生物传感器

制备了小于10 nm的金颗粒，并利用其进行固定化葡萄糖氧化酶和乳酸氧化酶的研究. 实验发现，金纳米颗粒可以大幅度提高葡萄糖氧化酶电极和乳酸氧化酶电极的电流响应，响应电流从相应浓度的几十纳安增强到几千纳安. 探讨了金纳米颗粒在固定化酶中所起的作用.     

葡糖氧化酶修饰碳纤维电极

研究了碳纤维电极经预处理后与葡糖酶的偶联行为，电化学氧化处理碳纤维的最佳时间是２ｍｉｎ，此法制得的碳纤维葡糖酶修饰电极活性期可达２个月以上。     

用氨基化硅胶和甲醛固定脂肪酶的研究

以甲醛为偶联剂,将脂肪酶固定在3-氨基丙基硅胶上。以差热分析法测试了自然酶和固定化酶的热稳定性,并研究了反应介质的温度和pH值对自然酶和固定化酶活性的影响。自然酶和固定化酶的最适pH值都在7.5附近,但固定化酶的最适温度较自然酶低。另外,还测试了固定化酶在37℃的磷酸盐缓冲溶液中贮存的稳定性,与自然酶相比其贮存的稳定性有显著的提高,同时发现固定化酶在37℃的磷酸盐缓冲溶液中有一个恢复活力的过程。     

Immobilization of polyphenol oxidase on alginate–SiO2 hybrid gel: stability and preliminary applications in the removal of aqueous phenol

An organic/inorganic hybrid gel of alginate–SiO₂ (ALG–SiO₂) was used to immobilize the partially purified potato polyphenol oxidase (PPO) for the treatment of phenolic wastewater. The influences of alginate concentration, quantity of both enzyme and tetramethoxysilane (TMOS) on immobilization were investigated. The Michaelis constant for immobilized PPO was determined as 14.7 mmol L⁻¹ at 25 °C, and the highest activity of immobilized PPO was achieved at pH 7.0. The ALG–SiO₂ immobilized PPO was more stable than the free PPO or ALG(alone) immobilized PPO. This study suggests that ALG–SiO₂ immobilized PPO might be a potential tool for the removal of phenolic compounds from industrial wastewater. Copyright © 2008 Society of Chemical Industry     

Mass transfer properties of bubble columns suspending immobilized glucose oxidase gel beads for gluconic acid production

The volumetric gas-liquid oxygen transfer coefficient, k_L a, and the liquid–solid coefficient, k_S, were measured in a 6.7 L external loop airlift bubble column (ELBC), a 2.5 L internal loop airlift (ILBC) and a 2.5 L normal bubble column (NBC) by the steady state method proposed previously using the oxidation of glucose with air catalyzed by glucose oxidase, GO. For an improved and simultaneous determination of k_L a and k_S, GO was entrapped in calcium alginate gel beads together with fine palladium particles instead of catalase to decompose the hydrogen peroxide produced. The gas holdup, ?_G, in each type of bubble column and the liquid circulation velocity, u_L, governing ?_G in the ELBC were also measured to correlate the data on k_La according to the previous correlations proposed for a larger scale of the ELBC, ILBC and NBC. The data on k_L a, k_S, ?_G and u_L (only for the ELBC) in the reaction system were compared to each other for the three types of bubble columns. The results are well predicted by the previous correlations.     

Optimization of L-Asparaginase Immobilization onto Calcium Alginate Beads

In this study, anti-leukemic enzyme L-asparaginase (E.C.3.5.1.1) from Escherichia coli ATCC 11303 was modified by the microencapsulation technique onto calcium alginate beads. Using response surface methodology (RSM), a three-level full factorial design, the values of concentration of sodium alginate, concentration of calcium chloride, and enzyme loading were investigated to obtain the highest residual L-asparaginase (L-ASNase) activity % (immobilized enzyme activity/free enzyme activity). The effects of the studied factors on immobilization were evaluated The predicted values by the model were close to the experimental values, indicating suitability of the model. The results presented that an increase in sodium alginate concentration increased the percent of residual activity of L-ASNase at any given calcium chloride concentration and the moderate amount of enzyme loading increased the percent residual activity. The optimal immobilization conditions were as follows: sodium alginate 1.98% (w/v), calcium chloride concentration 3.70% (w/v), and enzyme load 46.91% (v/v). The highest residual L-ASNase activity % obtained was 34.49%.     

钙离子对正渗透中海藻酸钠溶液污染特性的影响

研究钙离子对海藻酸钠溶液在正渗透过程中过滤行为的影响及其潜在机理.结果 发现,过滤含有低浓度Ca2+(1 mmol/L)的海藻酸钠溶液导致最大的水通量下降.增大Ca2+浓度(5、10、15 mmol/L)使得水通量下降减小.Ca2+浓度对海藻酸钠污染层的官能团组成没有显著影响,但污染层的微观结构受到Ca2+浓度的显著影...     

海澡酸钙胶囊化重组E.coli BL21(DE3)生产靛蓝(英文)

The ability of catalyzing indole into indigo of gene engineering strain expressing P450 BM3 immobi- lized by entrapment in calcium-alginate gel capsules was examined,and various characteristics of immobilized cells were assessed.Optimum conditions for cells activity were not affected after immobilization,and pH and tempera- ture for both free and immobilized cells were found to be pH 7.5 and 35℃,respectively.The immobilized cells ex- hibited a markedly improved thermal stability than free cells.After five repeated experiments,the yield of indigo with the immobilized cells retained over 94%of their original activity,which indicated that the operational stability for recycling in batch processes was improved.     

Continuous Production of Uniform Calcium Alginate Beads by Sound Wave Induced Vibration

A new process for the immobilization of sodium alginate, which employs a vibration of membrane induced by sound waves from a horn-type speaker, is developed to produce uniformly-sized beads of predictable diameter. Frequency of sound wave and production rate are varied to find the optimal control ranges for the bead production. The controllable bead size range is 1·50–3·50 mm and the experimental production rates are 0–12 dm³ h^-1 by a single nozzle. This method of bead production is a practical alternative to conventional continuous bead production methods with low apparatus cost and easier and better control of bead size and shape.