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1.
海藻酸钠和壳聚糖聚电解质微胶囊及其生物医学应用   总被引:10,自引:0,他引:10  
本文综述了天然多糖聚电解质海藻酸钠和壳聚糖的结构与化学性能(包括凝胶性能、生物相容性、生物可降解性及温和反应性);微胶囊制备技术及其强度性能和膜渗透性评价方法;微胶囊作为细胞载体在体内分泌治疗性物质(如:胰岛素、多巴胺)或分解代谢毒性物质(如:尿素),作为三维药物筛选系统、干细胞增殖分化研究工具,以及药物释放载体等生物医学领域的研究进展;最后讨论了天然多糖微胶囊研究与应用中需要解决的问题。  相似文献   

2.
壳聚糖溶液pH对载细胞海藻酸钠-壳聚糖微胶囊性能的影响   总被引:8,自引:0,他引:8  
以激光共聚焦扫描显微镜为研究手段, 原位直观地考察了在不同pH条件下聚电解质膜的络合程度和蛋白扩散情况. 通过分析pH值对微胶囊膜性能的影响规律, 并结合不同种类细胞对环境pH的敏感特性, 确定了制备细胞培养用海藻酸钠-壳聚糖微胶囊的最佳pH值. 结果表明, 当壳聚糖溶液的pH值由3.50增加到6.50, 微胶囊膜的络合深度呈现高-低-高的趋势, 而微胶囊膜的膨胀性能呈现低-高-低的趋势, 模型蛋白通过微囊膜的扩散呈现低-高-低的趋势, 拐点均出现在pH=4.00和5.50处. 结合动物细胞及微生物细胞对环境pH耐受能力的考察, 确定制备微囊化动物细胞时, 微胶囊成膜反应溶液的最佳pH值为5.50; 制备微囊化大肠杆菌时, 反应溶液的最佳pH值为5.00; 制备微囊化酵母菌时, 反应溶液的最佳pH值为4.50.  相似文献   

3.
采用响应面法优化了海藻酸钠-壳聚糖-粉末活性炭生物微胶囊(SA-CA-PAC)的制备工艺.在单因素实验的基础上.应用PIackett-Burman实验设计筛选影响微胶囊机械强度的重要参数,采用最陡爬坡实验逼近最大区域后,利用Box-Behnken设计确定重要参数的最佳水平.结果表明,影响微胶囊机械强度的重要参数为壳聚糖...  相似文献   

4.
磁性微胶囊的制备及其药物缓控释性能   总被引:2,自引:0,他引:2  
用乳液-凝胶法制备了磁性壳聚糖/海藻酸钠微胶囊. 在壳聚糖/海藻酸钠微胶囊中掺入Fe3O4磁性中空球, 使微胶囊具有磁靶向性能. 以头孢拉定作为模型药物研究了载药磁性微胶囊的载药量、包封率及药物缓控释性能等. 结果表明, 提高头孢拉定的初始浓度可以提高载药量, 却不利于提高药物的包封率. 所制备的微胶囊在各种缓冲溶液中长时间内具有显著的缓释效果, 并具有pH 刺激响应释放的性能, 即在模拟胃液中的药物释放率大大降低, 而在模拟体液和肠液中的释放时间大大延长, 可达50 h以上. 另外, 在外加磁场作用下, 微胶囊表现出良好的磁定向运动性能, 为磁靶向药物输送提供基础.  相似文献   

5.
壳聚糖/生发药物缓释膜的制备及性能   总被引:6,自引:0,他引:6  
孟平蕊  李良波  张建群  王玲 《化学通报》2002,65(12):836-839
报道了壳聚糖生发药物缓释膜的制备、性能。确定了壳聚糖溶液成膜的最佳条件 ,用 3 5× 1 0 -5mol L壳聚糖溶液、0 2mol L的乙醇和少量甘油 ,制备的壳聚糖膜抗拉强度为 5 3 5 0 8N m。用UV分光光度法测定了生发药物缓释膜在水中的释放速率 ,对膜的缓释机理进行了初步探讨  相似文献   

6.
微胶囊膜表面化学组成的XPS分析   总被引:1,自引:0,他引:1  
采用XPS表面表征技术对生物微胶囊膜表面化学组成进行了分析。结果表明,海藻酸钠_壳聚糖_海藻酸钠(ACA)微胶囊表面带负电荷的含C基团与带正电荷的含N基团的相对百分含量分别为30·6%与60·4%,而海藻酸钠_聚赖氨酸_海藻酸钠(APA)微胶囊分别为42·3%与30·0%,因此ACA微胶囊表面比APA微胶囊带更多的正电荷,更有利于蛋白质吸附与细胞粘附。为深入了解生物微胶囊表面引起的机体反应过程、改进微胶囊性能,提供了理论依据。  相似文献   

7.
海藻酸钙-壳聚糖微胶囊组成对BSA通透性能影响的研究   总被引:1,自引:0,他引:1  
邢楠  田丰  刘圣军  杨健  陈世谦  赵永亮 《化学学报》2007,65(24):2952-2958
对海藻酸钙-壳聚糖微胶囊的牛血清白蛋白(BSA)双向通透性能进行了定量和定性的初步研究, 并初步考察了微胶囊的组成成分及海藻酸钠、壳聚糖的溶液浓度对BSA通透性能的影响. 结果表明海藻酸钙-壳聚糖微胶囊在pH 1.5~2.0时通透性减弱, pH 6.8时通透性增强, 且海藻酸钙微胶囊通透性大于海藻酸钙-壳聚糖微胶囊; 海藻酸钙-壳聚糖微胶囊中壳聚糖浓度越小, 通透性越好; 海藻酸钠浓度的影响不显著.  相似文献   

8.
李朝霞 《化学通报》2007,70(3):228-232
测定不同分子量的聚乙二醇(PEG)溶液透过海藻酸钠-壳聚糖-粉末活性炭(SA-CA-PAC)生物微胶囊的性能,确定了SA-CA-PAC膜的截留分子量在PEG4000以下。研究了葡萄糖、乳糖、氨基酸等小分子的物质在SA-CA-PAC微胶囊中的扩散性能,用数学模型计算出了这些物质在微胶囊的混合扩散系数Dm以及相应的微胶囊膜层中扩散系数D1,结果表明小分子量的物质具有较好的扩散性能,且Dl<相似文献   

9.
壳聚糖—海藻酸钠微囊对蛋白质控制释放的研究   总被引:18,自引:2,他引:16  
采用乳化法制备了可注射用壳聚糖-海藻酸钠微囊,其粒径小于200μm,且具有相对较窄的近似高斯分布。牛血清白蛋白作为模型药物在微囊中的包埋率可超过50%。通过壳聚糖在海藻酸钠微囊表面的复合,牛血清白蛋白从微囊中的持续释放时间从几个小时延长到半个月以上。  相似文献   

10.
载细胞海藻酸钠/壳聚糖微胶囊的化学破囊方法研究   总被引:19,自引:0,他引:19  
以海藻酸钠-壳聚糖-海藻酸钠微胶囊(简称ACA微胶囊)为研究体系,建立了一种生理条件下ACA微胶囊的化学破囊方法,破囊过程充分考虑了对囊内生物物质活性的保持.以微生物细胞PichiapastorisGS115和动物细胞L929为模型,以NaHCO3和Na3C6H5O7·2H2O为破囊液基本组分,考察了破囊液对ACA微胶囊的破囊效果及破囊过程对囊内细胞活性的影响.结果表明,破囊操作可在30s内完成,破囊率为100%,微胶囊膜完全溶解,破囊后细胞存活率在85%以上.  相似文献   

11.
臭氧降解法制备壳低聚糖及其结构表征   总被引:3,自引:0,他引:3  
以85%脱乙酰度、相对分子质量为25×10^4的壳聚糖为原料,在20℃、pH为3、氧气流量0.7m^3/h的条件下降解6h,降解液用氨水调至pH为9,无沉淀,分别用截留相对分子质量为2k、3k、5k、10k的中空纤维膜超滤,获得所需聚合度的壳低聚糖。降解产物的结构用红外光谱、核磁共振碳谱表征,结果说明降解前后的结构基本没有变化。降解产物的聚合度用飞行时间质谱表征,其中经过2k中空纤维膜超滤后的壳低聚糖聚合度主要为4~10。  相似文献   

12.
The degradation behavior of porous scaffolds plays an important role in the synthesis of new tissue. In this study, three-dimensional hybrid porous scaffolds of chitosan (CS) comprised of nanostructured carbon (graphene oxide (GO) and single-walled carbon nanohorns (SWCNH)) were prepared by freeze-drying method. In-vitro degradation behavior of scaffolds was investigated up to 8 weeks in phosphate buffer saline (PBS) solution at 37 °C. The characteristics of scaffolds explored as a function of degradation time include crystalline structure, pore morphology, molecular weight, and wet/dry weight. The pH value of the PBS solution during degradation was also monitored. The study demonstrates for the first time that hybrid chitosan scaffolds with nanostructured carbon (GO and SWCNH) are potentially more stable than pure chitosan scaffolds during the time period required for tissue regeneration. The stability of hybrid scaffolds is attributed to nanostructured carbon that was processed with the objective that it is present in a robust manner via a highly cross-linked dense network structure. The chemical structure of chitosan was disrupted within a short period of two weeks, while disruption occurred in hybrid scaffolds after eight weeks. This was accompanied by a weight loss of ∼28% in pure chitosan and ∼20% in hybrid scaffolds. Furthermore, the degraded products were of low molecular weight in pure chitosan and high molecular weight in hybrid chitosan scaffolds. This led to significant decrease in the pH of solution to ∼6.2 in pure chitosan and to ∼7.2 in hybrid scaffolds. The observations clearly underscore that the introduction of GO and SWCNH via cross-link mechanism in CS is a potentially viable approach to tune the degradation rate of hybrid scaffolds in tissue engineering.  相似文献   

13.
丙烯酸交联壳聚糖渗透汽化膜研究(Ⅱ)──乙醇/水混合液的渗透汽化分离性能钟伟,李文俊,葛昌杰,陈新(复旦大学高分子科学系,上海,200433)关键词交联壳聚糖,渗透汽化,丙烯酸,乙醇/水混合液混合液体的渗透汽化(简称PV)膜分离自80年代实现工业化以...  相似文献   

14.
基片在两种带有相反电荷的聚电解质溶液中交替吸附 ,其表面形成致密有序的超薄膜的自组装 (ESA electrostaticself assembly)技术是由Decher及其合作者在 1 991年提出[1] ,由于简单易行 ,从一出现就受到了广大研究者的极大兴趣[2~ 4 ] .对生物材料来说 ,这无疑是一项非常重要且方便的表面改性手段 .因为生物材料在生物体内种植时 ,是否会被机体视为异物 ,关键在于机体与材料表面的相互作用 ,而与材料的本体性质基本无关[5] .因此利用这种技术 ,可对生物材料 ,特别是对那些生物相容性不好的材料表面进行…  相似文献   

15.
In this study, a simple method was developed to crosslink chitosan using poly(ethylene glycol) (PEG) with different molecular weights. Crosslinking of chitosan was confirmed by various spectral analyses. The differential scanning calorimetric (DSC) study indicated that the rigid crystalline structure of chitosan was decreased after crosslinking with PEG. The PEG-crosslinked chitosan (PEG-Ch) showed a pH-independent swelling behavior: swelled in both the simulated stomach (pH 1.1) and intestinal (pH 7.4) solutions. The swelling ratio of PEG-Ch increased significantly with a higher molecular weight of PEG used. In contrast, chitosan dissolved completely in a simulated stomach solution and showed a comparatively less swelling in a simulated intestinal solution. Thus, the prepared PEG-Ch could be a better biomaterial than chitosan in the development of orally sustained drug-delivery devices.  相似文献   

16.
Jiang H  Wang Y  Huang Q  Li Y  Xu C  Zhu K  Chen W 《Macromolecular bioscience》2005,5(12):1226-1233
An ampholytic N-carboxyethyl chitosan (CEC), with various isoelectric points (IPs), was synthesized by grafting acrylic acid on chitosan utilizing Michael's reaction. Compared to native chitosan, CEC has enhanced water solubility and dramatically accelerated enzymatic degradation; the rate of degradation is proportional to the degree of substitution (DS). The results from turbidimetric titration and fluorescence studies revealed that CEC formed complexes with either hyaluronic acid (HA) or bovine serum albumin (BSA) within a certain pH range. The HA/CEC/BSA ternary complexes could be prepared by colloid titration with quantitative yield and BSA entrapment. The rate of BSA release from the complexes was affected by pH, ionic strength, DS of CEC, and the molecular weight (MW) of HA. The endurance of BSA release from the complexes could be extended up to 20 d by formulating them with high-MW HA and CEC with low DS.BSA release profiles from HA/CEC-2/BSA complexes.  相似文献   

17.
To investigate the formation of positively charged nanoparticles (NP) stabilized with chitosan, positively charged poly(butyl cyanoacrylate) (PBCA) NP were prepared by emulsion polymerization in the presence of chitosan as a polymeric stabilizer at low pH. The effect of physicochemical factors such as the pH, the concentration and the volume of the chitosan solution, the chitosan molecular weight and the temperature on the mean particle size and the turbidity of PBCA-NP was investigated. Particle size was determined using a transmission electron microscope. The chemical interaction between chitosan and PBCA was identified by Fourier transform infrared (FT-IR) spectroscopy and the grafting percentage at various pH values was determined. The zeta potential of PBCA-NP coated with chitosan was determined from the electrophoretic mobility in 10 mM NaCl. The pH, the concentration and the volume of the chitosan solution and the molecular weight of chitosan were shown to be important factors in controlling the mean particle size of NP in the range 10–100 nm. FT-IR spectra indicated that chitosan was covalently linked to PBCA and the maximum grafting percentage reached about 120% w/w at pH 2.0. Nimodipine as a model drug was successfully incorporated into chitosan-stabilized PBCA-NP with a mean particle diameter of 31.6 nm. PBCA-NP coated with chitosan carried a positive charge. The results indicate that positively charged NP may be produced in the presence of cationic polysaccharide chitosan and might increase their potential use as a targeting drug delivery system. Received: 17 March 1999/Accepted in revised form: 4 October 1999  相似文献   

18.
壳聚糖在水溶液中的辐射降解反应   总被引:1,自引:0,他引:1  
研究了壳聚糖在CH3COOH/NaCl缓冲溶液均相体系下的辐射降解反应,给出了H2O2、异丙醇、pH、样品初始分子量等因素对壳聚糖降解的影响,探讨了实验条件下溶液中不同自由基对壳聚糖降解的作用,并对辐照前后壳聚糖的结构进行了表征.结果表明,酸性条件下,壳聚糖的降解主要由.H和.OH自由基共同作用引起,加入H2O2或者通入N2O都能够略微提高.OH自由基浓度,对壳聚糖的降解有促进作用.加入异丙醇后,由于同时降低了.H和.OH自由基浓度,导致壳聚糖降解缓慢.当溶液的pH接近中性后,对壳聚糖的降解起主要作用的为.OH自由基,加入H2O2或者通入N2O都会增加.OH自由基的浓度,从而明显提高壳聚糖的降解速率.此外,研究发现低分子量的壳聚糖具有较快的降解速率.样品的UV、FTIR分析表明,辐照后除在壳聚糖分子链端生成羰基外,壳聚糖主链结构未见变化,脱乙酰度也没有显著改变,显示出辐射降解是一种有效的控制壳聚糖分子量方法.  相似文献   

19.
壳聚糖对Zn2+的吸附性能研究   总被引:17,自引:1,他引:16  
本文用壳聚糖对Zn^2+的吸附条件进行了研究,探讨了脱乙酰度,分子量,粒度大小,溶液的pH值,温度,Zn^2+起始浓度和不同锌盐等方面对壳聚糖吸附性能的影响。结果表明:壳聚糖对Zn^2+的吸附具有Langmuir吸附特征,其吸附最佳条件是壳聚糖脱乙酰度为100%,锌盐为硫酸锌,Zn^2+溶液pH值为6.0,起始浓度4-5mg/ml。  相似文献   

20.
羧甲基壳聚糖对铅离子的吸附性能研究   总被引:23,自引:0,他引:23  
本文研究羧甲基壳聚糖对Pb^2 的吸附作用,探讨反应时间,离子强度,溶液的PH值、羧甲基取代度,温度等因素对吸附性能的影响,结果表明羧基是吸附Pb^2 的主要活性基团,羧甲基壳聚糖对Pb^2 的饱和吸附量为3.1083mmol/g,吸附Pb^2 的能力比壳聚糖,水溶性低聚壳聚糖强。  相似文献   

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