温度/pH双敏型羧甲基壳聚糖/海藻酸钠凝胶微球的制备

以羧甲基壳聚糖和海藻酸钠为基材,氯化钙和戊二醛混合液为交联剂,制备温度/p H双敏型凝胶微球。以溶胀度为主要考察指标,采用单次单因子法得到了较适宜的制备条件:2%的羧甲基壳聚糖/海藻酸钠混合溶液和5%的氯化钙/戊二醛混合交联剂的配比均为1∶1(质量比),交联剂的p H为6.8⁷.4,交联温度为40℃。在此条件下制得的凝胶微球,溶胀度随p H和温度的升高均表现出先升高后降低的趋势,当p H和温度分别为7.4和45℃时溶胀度最大,具有明显的p H和温度敏感性,适用于作为药物控释载体材料。     

羧甲基壳聚糖/海藻酸钠复合止血微球制备工艺研究

采用羧甲基壳聚糖和海藻酸钠为基质原料,以戊二醛与氯化钙为复合交联剂,采用乳化交联法制备复合止血微球。以其溶胀率为指标,通过单因素实验研究复合止血微球制备的影响因素;基于单因素实验结果,采用BoxBehnken响应面法(RSM)优化制备工艺。结果表明,复合微球的最佳工艺条件为:羧甲基壳聚糖/海藻酸钠质量比为1∶1,5%氯化钙8 mL,乳化剂Span-80浓度2%。在此条件下,复合微球的溶胀率为302.62%,具有显著的体外促凝血活性。     

羧甲基壳聚糖/海藻酸钠复合止血微球制备工艺研究

采用羧甲基壳聚糖和海藻酸钠为基质原料,以戊二醛与氯化钙为复合交联剂,采用乳化交联法制备复合止血微球。以其溶胀率为指标,通过单因素实验研究复合止血微球制备的影响因素;基于单因素实验结果,采用BoxBehnken响应面法(RSM)优化制备工艺。结果表明,复合微球的最佳工艺条件为:羧甲基壳聚糖/海藻酸钠质量比为1∶1,5%氯化钙8 mL,乳化剂Span-80浓度2%。在此条件下,复合微球的溶胀率为302.62%,具有显著的体外促凝血活性。     

高效氯氰菊酯/海藻酸钠/壳聚糖凝胶微球的制备

采用复凝聚相法以海藻酸钠和壳聚糖为材料制备了高效氯氰菊酯微球,以微球粒径和机械强度为主要性能指标,确定了较适宜制备条件:海藻酸钠质量分数为3%,乳化剂吐温-20为3%,OP-10-P为1%,氯化钙质量分数为2%,壳聚糖质量分数为0.6%,制得的复合微球载药率为22.33%,包埋率为76.17%,粒径为1.5 mm左右,具有良好的强度和稳定性。     

高效氯氰菊酯/海藻酸钠/壳聚糖凝胶微球的制备

采用复凝聚相法以海藻酸钠和壳聚糖为材料制备了高效氯氰菊酯微球,以微球粒径和机械强度为主要性能指标,确定了较适宜制备条件:海藻酸钠质量分数为3%,乳化剂吐温-20为3%,OP-10-P为1%,氯化钙质量分数为2%,壳聚糖质量分数为0.6%,制得的复合微球载药率为22.33%,包埋率为76.17%,粒径为1.5 mm左右,具有良好的强度和稳定性。     

羧甲基壳聚糖离子配位微球的制备及性能研究

以羧甲基壳聚糖(CMCHS)为主要原料,采用静电脉冲液滴发生器制备羧甲基壳聚糖离子配位微球。光学显微镜观察微球具备规整形貌,扫描电镜分析显示干球粒径约为100μm且表面呈多孔结构;红外光谱证明其内部具有由CMCHS上的羧酸根与Ca^2 配位形成的羧酸盐结构。溶胀实验表明,CMCHS溶液浓度、金属离子种类及其浓度等制备条件均影响微球的溶胀性能．且其溶胀行为对pH值较敏感。药物体外释放初步研究表明,CaCl2浓度和释放介质pH值均对微球的释放性能产生影响。研究对其进一步应用于药物释放等领域具有重要意义。     

吡虫啉/羧甲基壳聚糖凝胶球的制备及释放性能

以羧甲基壳聚糖为载体材料,吡虫啉为模型药物,采用双组分交联剂的悬浮交联法制备了吡虫啉/羧甲基壳聚糖凝胶球,采用扫描电镜和红外光谱对凝胶球进行了表征,探讨了制备工艺条件对凝胶球性能影响,利用体外释放实验测定了交联羧甲基壳聚糖凝胶球的释放特性。研究表明,采用氯化钙-戊二醛双组分交联剂可获得外形规整而表面带有皱褶的载药凝胶球;交联凝胶球中吡虫啉与羧甲基壳聚糖间无化学键合;交联凝胶球的载药量和包封率随交联时间和氯化钙浓度的增加呈先升后降趋势,随戊二醛体积分数的增加呈显著下降趋势;吡虫啉释放速度,随交联剂中氯化钙浓度和戊二醛体积分数的增加呈先降后增趋势;随交联时间变化不显著。在较佳条件下可制备载药量为25.71%的吡虫啉/羧甲基壳聚糖凝胶球,控释时间可达6 d;释放机理初步确定为Super CaseⅡ型传递机理。     

单宁酸对海藻酸钠/壳聚糖微球性能的影响

研究了单宁酸的引入对海藻酸钠/壳聚糖水凝胶在微球化和微胶囊化应用性能方面的影响.首先制备了单宁酸交联改性的海藻酸钠/壳聚糖水凝胶微球.利用傅里叶变换红外光谱分析了共混物分子结构间的相互作用,采用热重分析仪考察了微球热稳定性,并研究了单宁酸的加入对微球粒径、含水量和溶胀性的影响.结果表明由于单宁酸与海藻酸钠/壳聚糖之间的...     

膨润土对海藻酸钠/壳聚糖凝胶微球性能的影响

为了得到一种对啶虫脒具有高负载率和良好的缓释性能的农药载体,以膨润土作为吸附剂,利用壳聚糖的成膜性,采用挤出外源凝胶法制备了啶虫脒凝胶微球。并通过FTIR、SEM、TG、溶胀实验和释药实验对其结构、形貌和性能进行表征。结果表明,所制得的凝胶微球的粒径为1.42～1.71 mm,膨润土可提高微球粒径与球形度,使啶虫脒的载药率和包封率分别由原来的4.16%和36.36%提升为4.91%和63.01%。壳聚糖与海藻酸钠通过静电作用形成了聚电解质复合物,辅助了钙离子交联,使啶虫脒的载药率和包封率分别由原来的4.16%和36.36%提升为5.23%和54.29%。膨润土表面含有大量的羟基,与海藻酸钠和壳聚糖形成氢键作用,可有效抑制海藻酸钙的大量溶胀,提高其缓释性能。     

温度/pH敏感型壳聚糖水凝胶的制备及其性能

以天然可降解高分子壳聚糖为载体,选择温度敏感单体N-异丙基丙烯酰胺以及pH敏感单体2-丙烯酰胺基-2-甲基丙磺酸,以偶氮二异丁腈为引发剂,N,N-亚甲基双丙烯酰胺为交联剂,通过自由基接枝共聚反应制备壳聚糖水凝胶。通过红外(IR)、扫描电镜(SEM)对其结构及形貌进行了表征,并探讨了影响水凝胶溶胀率的因素。结果表明,当单体配比NIPAM∶AMPS为6∶4、引发剂用量为单体总质量4%、交联剂用量为单体总质量的4%、反应温度为45℃形成的水凝胶在水中溶胀率可达95%左右。该水凝胶具有一定的温度和pH敏感性,预计在药物控释、组织工程、抗凝血材料等领域拥有广阔的应用前景。     

pH-sensitive hydrogel based on carboxymethyl chitosan/sodium alginate and its application for drug delivery

Carboxymethyl chitosan sodium salt (CMCS)/sodium alginate (SA), a pH-sensitive hydrogel composed of CMCS and SA crosslinked by 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide, has been evaluated in vitro as a potential carrier for protein drug delivery of bovine serum albumin (BSA). The crosslinked structures, pore morphologies, and mechanical properties of the composite CMCS/SA hydrogel at different pH have been characterized by Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and dynamic mechanical analysis (DMA). The swelling behavior of the prepared hydrogel was assessed at different pH values, 1.2, 4.0, 6.86, 7.4, and 9.0. The in vitro slow release ability of the CMCS/SA hydrogel was assessed at 37°C and pH 1.2 or pH 7.4 to simulate gastrointestinal and mouth environments in vivo. The efficiency was found to be greater than 90% at pH 7.4. The composite CMCS/SA hydrogel showed no cytotoxic effect toward L-929 cells according to the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test. These findings demonstrate that the composite hydrogel has promising potential for drug delivery. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 46911.     

疏水改性羧甲基纤维素及其pH敏感水凝胶的研究

通过羧甲基纤维素钠( CMC -Na)与脂肪酰氯在正庚烷介质中酯化反应制备疏水改性羧甲基纤维素(Ln-CMC -Na),讨论了物料比、温度和时间对反应的影响,确定了适宜的反应条件.根据Ln-CMC -Na的水溶性,确定在脂肪酰氯与CMC -Na摩尔比为0.08时,分别用十、十二、十四、十六和十八酰氯制备出系列改性产品,并测定了其HLB值、表面张力和临界胶束浓度.以三氯化铝为交联剂,Ln-CMC -Na作配体制得pH敏感水凝胶.     

Preparation and swelling kinetics of pH-sensitive photocrosslinked hydrogel based on carboxymethyl chitosan

A series of photocrosslinkable carboxymethyl chitosans were synthesized by mixing azidobenzaldehyde and an aqueous solution of carboxymethyl chitosan. Aqueous solutions of the product were photocrosslinked via UV irradiation to afford hydrogels. The morphologies and the mechanical properties of the hydrogels were characterized. Their swelling kinetics were studied. The hydrogels displayed good pH sensitivity in pH 2.2–8.0 buffer solutions and an overshooting effect during swelling in pH <5 buffer solutions. The following three factors may contribute to this overshooting effect: firstly, because of the protonation of amide groups in the network in acidic solution, the formation of ionic bonds between amine ions and partial carboxylic ions causes the release of solvent from the swollen network; secondly, ionized carboxylic groups in the network become protonated and convert into nonionized carboxylic groups, and so the concentration of free counterions within the network gradually decreases in acidic solution, leading to solvent release; finally, hydrogen bonds gradually form between nonionized carboxylic groups on the network, which also leads to solvent release from the swollen network. In pH ≥ 5 buffer solutions, the overshooting effect disappeared and the swelling kinetics followed Schott’s second-order swelling kinetics.     

海藻酸钠/羧甲基壳聚糖纺丝溶液的流变性能

采用RT-2000毛细管流变仪,研究了海藻酸钠(SAL)/羧甲基壳聚糖(CMCS)纺丝溶液的流变性能。结果表明:SAL/CMCS纺丝溶液是切力变稀型流体,随着剪切速率(γ)的增加,纺丝溶液的表观粘度(η_a)下降;随着纺丝液中CMCS含量的增加,SAL/CMCS纺丝溶液的η_a和结构粘度指数(△η)下降,非牛顿指数(n)增大;随着纺丝液温度的升高,SAL/CMCS纺丝溶液的η_a和△η下降,n增大。纺丝过程中应控制SAL/CMCS纺丝溶液的温度为35℃,纺丝溶液中CMCS质量分数为15%较适宜。     

MWCNTs reinforced conductive,self-healing polyvinyl alcohol/carboxymethyl chitosan/oxidized sodium alginate hydrogel as the strain sensor

The preparation and application of hydrogel has been a hot research field in recent years. Here in, a composite hydrogel based on poly(vinyl alcohol) (PVA), carboxymethyl chitosan (CMCS), oxidized sodium alginate (OSA), and oxidized multiwall carbon nanotubes (OMWCNTs) was successfully prepared. Hydrogen and imine bonds of the hydrogel endowed the composite hydrogel with self-healing property and pH sensitivity. The fracture strength of the hydrogel was enhanced to about 0.8 MPa with the help of OMWCNTs, which was about 2.5 times compared with the one without OMWCNTs. Meanwhile, a new conductive network inside the hydrogel was constructed by OMWCNTs, which improved the conductivity of the hydrogel from 1.75 × 10⁻⁴ to 7.02 × 10⁻⁴ S/cm. The sensing test of the hydrogel showed that it could produce profound feedback signals for the deformation caused by external force and response to human body movements, such as finger bending, swallowing, and speaking.     

海藻酸钠/壳聚糖微载体的制备及生物活性评价

以壳聚糖为基质,通过共混法引入海藻酸钠,采用乳液冷冻干燥法,并结合正戊醇和醋酸铵作致孔剂,制备海藻酸钠/壳聚糖多孔微载体,并在该微载体上培养人肝细胞L-02。通过扫描电子显微镜来观察微载体的微观结构形貌,并通过红外光谱、溶胀性、吸水率、体外降解率、MTT比色法等手段来综合评价海藻酸钠/壳聚糖微载体的性能及生物活性。结果表明,致孔剂不同,则得到的微载体的表观形貌也不同。以正戊醇为致孔剂进行冻干得到的微载体孔径为3～50μm,孔隙率为93%;以正戊醇和醋酸铵2种致孔剂来制孔得到的微载体孔径为15～55μm,孔隙率为94%。且2种方法得到的微载体硬度高,溶胀性良好,吸水率高,空白海藻酸钠/壳聚糖微载体在体外可完全降解。红外光谱显示,海藻酸钠/壳聚糖微载体中,壳聚糖分子链上的氨基和乙酰胺基都与海藻酸钠分子链上的羧酸盐官能团存在很强的静电相互作用。光学显微镜观察L-02人肝细胞在海藻酸钠/壳聚糖微载体上生长良好。