Mitochondria-targeted ratiometric fluorescent probes for micropolarity and microviscosity and their applications

Two fluorescent "off-on" probes YYH1 and YYH2 were used for bioimaging mitochondrial polarity and viscosity.     

Mixed micelle behavior of poly(ethylene glycol) alkyl ethers with series of monomeric cationic, phosphonium cationic, and zwitterionic surfactant

The steady state fluorescence measurements have been carried out for the binary mixtures of poly(ethylene glycol) alkyl ethers (C _i E _j ) with series of monomeric cationic (MC), zwitterionic (ZI), and phosphonium cationic (PC) surfactants over the whole mole fraction range by using pyrene as fluorescence probe. The cmc values for all the binary mixtures, thus, determined have been further evaluated by using the regular solution theory. The various micellar parameters such as regular solution interaction parameter (β), micropolarity (I ₁/I ₃), and mean micelle aggregation number (N _agg) have been determined. A strong influence of hydrophobicity of both nonionic as well as cosurfactant (CS) components has been observed on the nature of mixed micelles. The presence of bulky head groups of PC surfactants significantly contributes towards the unfavorable mixing.     

Triton X-100/正癸醇/水层状液晶制备泡囊

利用层状结构在超声振荡下可以弯曲变形的特点 ,以TritonX 100/n C10H21OH/H2O体系生成的层状液晶为介质制备泡囊,所得泡囊分布比较均匀 ,囊径在0.2～0.5μm之间.研究了层状液晶组成、pH、超声振荡时间等因素对所制泡囊的 ζ电位及微极性的影响.     

十一烯酸钠与十一酸钠水溶液的表面化学

决定表面活性剂性能的首要因素是其分子结构．关于表面活性剂性能随极性头类型、疏水基化学组成、疏水链数目、长度及分支等因素的影响已有许多研究[1]．相比之下，疏水基中含有双键的影响研究较少．实际上，在由两亲分子组成的生物膜中，不饱和脂肪酸酯的存在有重要意义，它使     

十六烷基二苯醚二磺酸钠分子有序聚集体的研究

采用芘为荧光探针、二苯甲酮为猝灭剂，以分子荧光探针法首次测定了由刚性基团联接的特殊双亲水基型阴离子表面活性剂——十六烷基二苯醚二磺酸钠(C16-MADS)的胶束聚集数(Nm)，并考察了表面活性剂浓度、无机盐浓度和温度对Nm的影响。结果表明，表面活性剂的浓度必须高于临界胶束浓度(cmc)一个数量级时，才能测定出较为合适的Nm；随着C16-MADS浓度的增大，Nm增大，胶束内核的微极性变小；而温度对Nm的影响极小。与传统的单亲水基阴离子表面活性剂相比，C16-MADS的有序聚集体表现出许多不同之处，如Nm仅为传统的单亲水基阴离子表面活性剂胶束聚集数的一半，无机盐浓度对Nm的影响极小，胶束内核的微极性明显增大。     

Proteolytic activity in various water-in-oil microemulsions as related to the polarity of the reaction medium

The catalytic behaviors of α-chymotrypsin and of trypsin were studied in anionic AOT-isooctane-water and cationic CTAB-ROH-isooctane-water microemulsion systems. The effects of various parameters, such as the pH and the water content expressed in terms of the molar ratio w_o = [H₂O]/[Surfactant], on the enzyme activity, were examined. The kinetic constants were calculated and it was found that in the case of trypsin the enzyme exhibited a remarkable “superactivityrd, when studied in the CTAB microemulsion systems. The effect of the alcohol cosurfactant used in these cationic systems was investigated in relation to the polarity of the reaction medium. By using the hydrophilic probe 1-methyl-8-oxyquinolinium betaine the micropolarity of the water core was determined and related to the kinetic results.     

Interaction of pyrene-end-capped poly(ethylene oxide) with bovine serum albumin and human serum albumin in aqueous buffer medium: a fluorometric study

The photophysical behavior of a hydrophobically tailored water-soluble polymer, pyrene-end-capped poly(ethylene oxide) (PYPY), has been studied in aqueous buffered bovine serum albumin (BSA) and human serum albumin (HSA) media. In buffered aqueous solution the polymer shows dual emission corresponding to the monomer and the excimer of pyrene moiety. The relative intensity of the monomer to the excimer emission shows interesting variation with the addition of BSA and HSA and is indicative of significant interaction of these albumin proteins with the polymer. The binding interaction has been shown to have a prominent role on the steady state fluorescence anisotropy of the two emission bands. Attempt has been made to determine the micropolarities of the protein microenvironments from a comparison of the variation of the monomer to excimer relative fluorescence intensities of the probe in water–dioxane mixtures with varying composition.     

Estimation of polarity and fluidity of colloidal interfaces and biosurfaces using rhamnolipid B pyrenacylester as surface-active fluorescent probe

Fluorescent probes are useful to monitor the polarity and fluidity of microenvironments. Therefore, a new amphiphilic fluorescent probe, the pyrenacylester of Rhamnolipid B, was prepared from biosurfactant (Rhamnolipid B) and pyrene. As a result of its surface activity, this probe was expected to be able to penetrate into various kinds of microdomains such as the environments of organic solvents, emulsions, dispersions, surfaces of biomembranes and polymers.     

表面活性素与三种长链烷基苯磺酸盐之间的相互作用

利用表面张力和荧光方法研究了表面活性素(surfactin)与3种长链烷基苯磺酸盐C16ABS、C17ABS和C18ABS之间的相互作用。计算了混合体系吸附单层和混合胶束中分子间的相互作用参数(βσ和βm)以及热力学性质。负的相互作用参数表明,尽管表面活性剂均为负离子型,存在静电排斥,但是混合后两者之间的排斥作用减弱,从而产生增效作用。这可能是由于烷基苯磺酸盐与surfactin在混合吸附单层和胶束中形成了一种既能减弱头基间静电排斥又能增强疏水链之间相互作用的空间结构所致。荧光结果显示,混合表面活性剂能形成更紧密、体积更大的聚集体,并且在高烷基苯磺酸盐含量时可能存在大型的棒、层状胶束或囊泡。     

pH对2RNC2水溶液囊泡及泡沫性质的影响

前文[1]报导了合成双烃链表面活性剂──双（月桂酸）三乙醇胺酯在酸性溶液中形成囊泡及其稳定性的规律．结果表明，当PH值小于4．2时，囊泡才能形成，其稳定性在PH值2~3范围内达到最佳效果．本工作应用DSC、荧光探针技术及起泡性实验研究PH对囊泡相变和微环境性质及溶液起泡性