N,N-双十二烷基化壳聚糖的制备

以十二烷基磺酸钠为相转移催化剂,通过月桂醛与壳聚糖反应形成Schiff碱,再用NaBH4还原合成N,N—双十二烷基化壳聚糖初产物。利用不同烷基化取代度的壳聚糖在氯仿溶剂中溶解度的差别,对初产物进行提纯,可溶于氯仿的产物的结构经红外光谱、核磁共振和元素分析等方法证明接近为完全N,N-双十二烷基化壳聚糖。     

N,N-双十二烷基壳聚糖自组装纳米药用泡囊的制备

采用逆相蒸发法首次制备N,N-双十二烷基壳聚糖自组装纳米药用泡囊。实验表明该自组装泡囊同时具有多层结构和多腔室结构,平均粒径在150m左右。N,N-双十二烷基壳聚糖自组装药用泡囊的维生素B12药物包封率为13．42％;载药量分别为0．06mg／mg。载药泡囊的体外药物释放可持续24h左右。     

O-季铵盐-N,N-双长链烷基壳聚糖的制备及其性能

在合成O-季铵化壳聚糖的基础上,再进行N,N-双烷基化改性,得到O-季铵盐-N,N-双烷基壳聚糖.用FTIR、1H NMR、EA等手段对产物的结构进行表征,并对其溶解性能和表面性能进行研究.实验结果表明:这种新型双亲性壳聚糖季铵盐与N,N-双烷基壳聚糖相比,水的表面接触角降低,亲水性能明显提高;产物除可溶于氯仿与四氢呋喃外,还可溶于N,N-二甲基甲酰胺和冰乙酸中,表现出更明显的双亲性.     

O-二酸单酯-N,N双长链烷基壳寡糖的制备及表征

壳寡糖与月桂醛反应生成Schiff碱,再用NaBH4还原合成N,N-双十二烷基化壳寡糖,然后在均相条件下与酸酐反应制备了含有不同亲水基团的新型双亲性壳寡糖衍生物:O-丁烯二酸单酯-N,N-双十二烷基壳寡糖(OBDCS)、O-丁二酸单酯-N,N-双十二烷基壳寡糖(OSDCS)和O-邻苯二甲酸单酯-N,N-双十二烷基壳寡糖(OPDCS)。用红外光谱、核磁共振和元素分析等方法对产物的结构进行了表征,并试验了其溶解性能。结果表明,改性产物的溶解性能明显优于未改性的N,N-双十二烷基壳寡糖,拓宽了壳寡糖的应用范围。     

N,N-双十二烷基壳聚糖/聚(L-乳酸)复合膜的氢键及相容性研究

以氯仿为共溶剂,通过溶液共混,制备了不同组成的N,N-双十二烷基化壳聚糖/聚(L–乳酸)(NCS/PLLA)复合膜。利用红外光谱、热分析、WAXD及SEM探讨了复合膜的氢键作用和相容性。红外分析表明,NCS随PLLA的加入,NCS的缔合羟基伸缩振动由3430cm-1红移至3 380 cm-1、谱带变宽、吸收增强;随NCS的加入,PLLA的羰基伸缩振动由1 760 cm-1红移到1 753 cm-1。热重及热重微分分析表明,复合膜的热稳定性高于纯NCS;DSC分析表明,NCS的加入使PLLA的Tm降低,结晶度下降。WAXD分析表明,NCS的加入使PLLA在2θ=16.7°和2θ=19.1°的结晶衍射峰往低角度偏移、峰变宽、峰强逐渐减弱,当NCS为50%和75%时,PLLA的结晶衍射峰消失。SEM观察表明NCS/PLLA复合膜无相分离。实验结果表明NCS与PLLA存在较强的氢键作用,复合膜具有良好的相容性。     

N,N-双烷基壳聚糖结构对其自组装泡囊性质的影响

合成了不同主链相对分子质量的N,N-双辛烷基壳聚糖,N,N-双癸烷基壳聚糖及N,N-双十二烷基壳聚糖,并制备了相应的自组装泡囊,比较研究了侧链长度和主链相对分子质量对载药泡囊药物释放行为的影响。结果表明这类N,N-双长链烷基壳聚糖可形成粒径为100～150 nm的泡囊。原子力显微镜表明,侧链长度对N,N-双烷基壳聚糖泡囊的曲率有较明显影响,主链相对分子质量对泡囊的粒径影响较大。药物释放行为表明,侧链长度或主链相对分子质量的增大会导致药物释放速率的降低,达到平衡时的药物释放率也较低,而其相应自组装泡囊的载药量和包埋率却有所提高。     

N,N-双十二烷基乙二胺的合成及摩擦学性能

以溴代十二烷和乙二胺为原料,通过亲核取代反应制备了N,N-双十二烷基乙二胺（C26H56N2）,通过实验考察了合成条件变化对N,N-双十二烷基乙二胺合成的影响。结果表明：在n(溴代十二烷)∶n(乙二胺)=2.4∶1、回流温度下反应8 h得到目标产物,收率为45.5%;利用FTIR、1H NMR、元素分析等手段对其结构进行了表征。探索了N,N-双十二烷基乙二胺作为润滑油添加剂的新应用。采用四球摩擦磨损试验考察了其在聚乙二醇400中的摩擦学性能。结果显示,当N,N-双十二烷基乙二胺添加量为2%时,聚乙二醇400的PB值可由696 N提高至862 N。     

N-十二烷基-N,N,N-三羟乙基氯化铵的物化性能研究

通过用滴体积法对合成纯化所得 N-烷基 - N,N,N-三羟乙基氯化铵 ( AEEC)表面张力测定发现 ,AEEC的表面过剩浓度随疏水基碳链数的增加而有所减小 ,表面分子面积受碳链长度影响 ;疏水基碳链的增加使 AEEC降低表面张力的效能和效率都提高 ;随着疏水基碳链的增加 ,AEEC的 CMC降低。并且在所测定的温度范围内 ,log CMC与疏水基碳链长度成线性关系。在 2 5°C时 ,TΔSomic对 ΔGomic的贡献比 ΔHomic大 ,并且碳链愈长 TΔSomic的贡献愈大 ,AEEC胶束化的主要驱动力是熵变。     

N-甲基-N,N-双十二烷基壳聚糖盐酸盐的合成及自组装囊泡性能

以壳聚糖为原料制备N-甲基-N,N-双十二烷基壳聚糖盐酸盐(TMC),用FT-IR、EA对产物进行表征,溶解性实验表明TMC溶于乙醇等有机溶剂。采用乙醇注射法制备TMC囊泡,研究不同pH值介质中制得的载亲/疏水药物TMC囊泡的Zeta电位、粒径大小及分布、储存稳定性、载药及释放性能。结果表明,制得的TMC自组装囊泡Zeta电位为39.5~46 mV,粒径为50~100 nm,多分散系数为0.17~0.26,静置30天后仍保持稳定。Langmuir膜行为表明在较低pH值下TMC更易自组装,制备介质pH值不同对囊泡的粒径、药物释放行为影响较大,而释药环境pH值对囊泡的药物释放行为影响较小。     

N,N-二(3-氨基丙基)十二烷基胺的合成工艺研究

以十二胺和丙烯腈为原料、在催化剂CR-1作用下制备了3-十二烷基胺基-二丙腈(十二Y型腈),并经加氢制备了N,N-二(3-氨基丙基)十二烷基胺(十二Y型胺)。考察了催化剂、反应时间、溶剂等因素对制腈工艺的影响。比较了不同抑制剂的对十二Y型腈加氢的影响,确定了合成十二Y型胺的工艺条件,并通过GC和GCMS对产品进行了表征。     

pH值响应聚乙二醇化壳聚糖基隐形纳米胶束的制备及其载药性能

聚乙二醇单甲醚(mPEG)先经过氯乙酸羧化后,再通过酰化反应接枝到双烷基壳聚糖上,制备高接枝度的N,N-双十二烷基-3,6-O-mPEG-壳聚糖(PEDLCS)双亲性衍生物,用¹H NMR、FTIR、EA等对产物进行表征,并用透析法制得PEDLCS载酮洛芬(KP)胶束。结果表明,PEDLCS在水溶液中能自组装形成胶束,CMC值为0.1170mg/mL;载药胶束的最优投料比为KP/PEDLCS=0.8:1,载药量34.48%,包封率65.78%,粒径155.1nm,Zeta电位-31.6mV。载药胶束在不同pH值条件下的响应性实验表明,随着pH值的减小,胶束的稳定性降低,胶束粒径变大,具有可逆性。pH值响应范围符合肿瘤细胞微环境(pH值为7.2～6.0),有望成为具有pH值响应主动靶向的隐形纳米胶束。     

黏膜粘附性缺氧响应型壳聚糖胶束的制备与性能

以2-硝基咪唑和6-溴己酸乙酯为原料，合成了缺氧响应型6-(2-硝基咪唑)己酸（NIHA），将其接枝改性壳聚糖合成了取代度分别为3.9%、6.3%和8.9%的两亲性壳聚糖-g-6-(2-硝基咪唑)己酰胺衍生物（CS-NID）。利用1HNMR、UV和FTIR表征了CS-NID的化学结构。CS-NID在水中能自组装形成纳米胶束，并采用DLS、Zeta电位和UV对胶束进行了表征。结果表明，CS-NID胶束的平均粒径为165~190 nm，粒径随NIHA取代度增加而减小。胶束具有优良的储存稳定性、黏膜粘附性、pH响应性和缺氧响应性。阿霉素（DOX）通过疏水相互作用被装载进胶束内，最大载药率（DLC）可达13.3%，最大包封率（DLE）可达44.3%。体外药物释放研究表明，CS-NID胶束具有明显的缺氧响应的药物释放行为，在正常生理环境（常氧，pH 7.4）中24h最大药物释放量仅为42%，而在缺氧的酸性（pH 5.4）条件下，2h内药物释放量高达65%，24h内药物释放量超过92%。     

Solubilization,micellar transition and biocidal assay of loaded antioxidants in Tetronic® 1304 micelles

The current study scrutinizes the solubilization behaviour of pharmaceutically active antioxidants, namely hydrocinnamic acid (HCA), cinnamic acid (CA) and phenyl propiolic acid (PPA), in the micelles of polyethylene oxide‐polypropylene oxide (PEO‐PPO) based star‐block copolymer: Tetronic® 1304 (T1304). A correlation between the molecular orbital energy levels of PEO‐PPO units of T1304 and the active parts of the antioxidants are well explained using a simulation study. The antioxidants modulate core–shell micelles of T1304 with enhanced solubilization dependent on their unsaturation and hydrophobicity, as depicted from UV–visible spectroscopy. Antioxidants as an additive induce micellization in 5% w/v T1304 thereby modulating the phase behaviour, as indicated by the decrease in the cloud point. The cloud point results are well complemented by steady state fluorescence spectroscopy findings, depicting a decrease in critical micelle temperature due to the solubilization of antioxidants into the T1304 micelles. A significant difference between the hydrodynamic diameter (D_h) of unloaded and loaded polymer micelles with antioxidants is observed from dynamic light scattering, ensuring the solubilization of the antioxidants in T1304 micelles. These results can apparently be attributed to the interaction and the charge induced by the antioxidants on non‐ionic T1304 micelles which increase the micellar size. Furthermore, the role of unsaturation and hydrophobicity of the employed antioxidants in 5% T1304 demonstrates the solution viscosity (η) change as a function of temperature. In addition, small‐angle neutron scattering depicts the shape transition (spherical to ellipsoidal to polymersomes) with temperature. The antioxidant loaded 5% T1304 micellar systems exhibit brilliant biocidal activity against the tested microbes, suggesting their antimicrobial application. © 2019 Society of Chemical Industry     

壳聚糖控制聚合氯化铝混凝残余铝的实验研究

为有效控制聚合氯化铝混凝残余铝对饮用水水质的影响,通过静态实验研究了壳聚糖对铝离子的吸附性能。针对磨盘山水库的低温低浊水,探讨了壳聚糖对聚合氯化铝混凝残余铝的去除作用,并与粉末活性炭的去除效果进行了比较。结果表明,壳聚糖对水中的铝离子具有较强吸附性能,符合Freundlich等温吸附模型;在聚合氯化铝混凝过程中投加0.2~0.4 mg/L壳聚糖能够有效降低残余铝,而达到相同效果时粉末活性炭的投加量为10~30 mg/L。     

跨尺度方法研究聚合物载药胶束的定量构性关系

以两亲性聚合物自组装载药胶束为案例, 基于宏观到微观的跨尺度方法研究化学产品的定量构性关系(QSPR), 提出嵌段单元自相关方法计算表征两亲性聚合物结构的描述符, 结合遗传函数算法和多元线性回归建立了不同药物/聚合物配比下聚合物胶束载药量的QSPR预测模型, 经内部验证(R²>0.854, Q_loo-cv²>0.651, RMSE<0.089)、Y-随机化检验和外部验证(Q_ext²>0.629), 以及应用域定义分析评估了模型的可靠性、稳定性和预测能力。通过对描述符的分析和载药机制解释, 很好地阐释了聚合物嵌段单元和聚合物拓扑结构对胶束载药量的影响。QSPR模型的建立将指导新聚合物及其载药胶束体系的设计, 并预测其载药能力, 这种跨尺度研究方法有望促进复杂结构化产品的设计和开发。     

Encapsulation of curcumin by methoxy poly(ethylene glycol‐b‐aromatic anhydride) micelles

Suitable carrier systems for sustained release of curcumin were studied by using the self‐assembled polymeric micelles. Poly(ethylene glycol) methyl ether and poly(aromatic anhydride) were used as the hydrophilic and hydrophobic blocks, respectively, in forming amphiphilic diblock copolymers. Four different types of polymers methoxy poly(ethylene glycol‐ b‐1,3‐bis(p‐carboxyphenoxy)propane) (mPEG₅₀₀₀CPP, mPEG₂₀₀₀CPP), methoxy poly(ethylene glycol‐b‐1,6‐bis(p‐carboxyphenoxy)hexane) (mPEG₅₀₀₀CPH, mPEG₂₀₀₀CPH) were synthesized via melt condensation approach. Micelles were formed at very low polymer concentration with stable hydrophobic cores. The particle sizes of micelles remained stable during degradation period. All four different polymeric micelles showed low cytotoxicity toward human fibroblasts cells and can kill cancer cells in very low concentrations. High loading efficiency and drug content were observed in curcumin‐loaded micelles. Curcumin showed mild initial burst (30% of drug loading in the first 24 h) when released from the micelles and its release was sustained for at least 18 days. These micelles, especially those of mPEG₅₀₀₀CPP, show potential to serve as the delivery vehicles for sustained release of curcumin. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

亲水基团性质对双亲性壳聚糖衍生物单分子膜性能的影响

制备了双亲性O-磺化-N,N-双十二烷基壳聚糖(HSDLCS)、O-季铵化-N,N-双十二烷基壳聚糖(QADLCS)和O-羟丙基-N,N-双十二烷基壳聚糖(HPDLCS),研究了不同亲水基团对产物单分子膜性能的影响。结果表明,与N,N-双十二烷基壳聚糖(DLCS)相比,引入亲水基团后的产物其单分子膜具有较高的崩溃压(π_c)和最大压缩模量(C_s^-1,_max),凝聚性更好。与非离子型产物HPDLCS相比,离子型产物具有较大的π_c和C_s^-1,_max,其中阴离子型产物HSDLCS单分子膜的π_c(44.64mN/m)和C_s^-1,_max(84.27mN/m)最大,阳离子型产物QADLCS(π_c,42.01mN/m;C_s^-1,_max,82.99mN/m)次之,HSDLCS单分子膜具有较强的凝聚性和抗形变能力。     

Homogeneous synthesis of linoleic acid‐grafted chitosan oligosaccharide in ionic liquid and its self‐assembly performance in aqueous solution

A water‐soluble amphiphilic derivative of chitosan oligosaccharide (COS) modified with linoleic acid (LA)‐grafted COS (LCOS) has been synthesized in the ionic liquid 1‐butyl‐3‐methylimidazolium acetate ([BMIM]Ac). The effects of the ionic liquid on the degree of substitution (DS), surface activity, and self‐assembly behavior of LCOS have been investigated. The results showed that the ionic liquid homogeneous system led to a relatively higher DS compared with the product synthesized in a traditional organic solvent. Furthermore, the LCOS synthesized in the ionic liquid had better surface activity (cmc = 1.1 × 10^?4 g·mL^?1), and could also self‐assemble into nanomicelles with better‐defined spherical shape and a narrower particle size distribution (30–40 nm) in aqueous solution. These results suggest that an effective and environmentally friendly synthesis method for COS derivatives has been established and, moreover, the obtained LCOS micelles meet the basic requirements for use as an improved drug transduction vector. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41727.     

Solubilization of octafluoronaphthalene by mixed micelles of fluorocarbon and hydrocarbon surfactants in aqueous solutions

Solubilization of octafluoronaphthalene (OFN) by fluorocarbon and hydrocarbon surfactants in aqueous solutions has been examined to investigate the effects of mixing surfactants and added salt. Diethylammonium perfluoronanoate (DEAPFN) micelles have the most solubilization power toward OFN. The difference in micellar solubilization power will be caused by the hydrophobicity of ionic groups and micellar size. Large positive synergistic effects on solubilization behavior were observed in the DEAPFN-diethylammonium tetradecyl sulfate mixed micellar systems. Solubilization of OFN depended on the concentrations of added salt and the aggregation number, that is, the micellar size.