JOURNAL OF CHEMICAL THERMODYNAMICS
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2016
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IF 2.196
Guangyue Bai,Jianhui Sheng,Yujie Wang,Hui Wu,Yang Zhao,Kelei Zhuo,Margarida Bastos
The thermodynamics of molecular self-assembling of an anionic biosurfactant, sodium cholate (NaCA) and its mixtures with sodium dodecyl sulfate (SDS) in aqueous solution have been investigated by isothermal titration calorimetry (ITC), along with fluorescence and conductivity measurements. Different critical concentrations were obtained by these three techniques – critical pre-micelle concentration (cmc pre ) and critical micelle concentration (cmc) for pure NaCA, and critical micelle concentrations (cmc mix ) for the mixed systems with differently initial SDS concentrations. Importantly, ITC allowed us to directly measure the enthalpy changes of pre-micelle formation (Δ H premic = (−0.28 ± 0.02) kJ·mol −1 ) and of micelle formation (Δ H mic = (−1.76 ± 0.05) kJ·mol −1 ) for pure NaCA as well as the enthalpies for micellization for the mixed systems NaCA/SDS. The non-ideality of the mixed surfactant solution was evaluated in terms of interaction parameters and excess enthalpies that were calculated in the light of Clint’s and Rubingh’s models. It was found that there is an obvious synergistic effect in the NaCA/SDS mixed system. From all these results we can ascribe the strong interaction between the same charge surfactants NaCA and SDS to the structural difference in their hydrophobic moieties. In fact, the flexible alkyl chains of SDS and the non-planar hydrophobic β -faces of NaCA tend to have a more compact packing than pure NaCA.
研究领域:
生物化学
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物理化学
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产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
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2014
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IF 2.423
Yujie Wang,Pengxiao Lou,Guangyue Bai,Caoying Fan,Margarida Bastos
The thermodynamics of the process of self-assembly of cationic gemini surfactants, [C 12 H 25 (CH 3 ) 2 N(CH 2 ) S N(CH 3 ) 2 C 12 H 25 ]Br 2 , (the spacer S being 2, 6 or 10, assigned as C 12 C S C 12 Br 2 ) and the system of oppositely charged mixture of surfactants formed by C 12 C S C 12 Br 2 and sodium cholate (NaCA) in aqueous solution has been investigated by isothermal titration calorimetry (ITC), conductivity and turbidity measurements. The critical micelle concentration values (cmc) for the gemini surfactants C 12 C S C 12 Br 2 obtained from calorimetry and conductivity were found to be consistent with values reported in the literature. The enthalpies of micellization (Δ H mic ) of C 12 C S C 12 Br 2 are all exothermic, presenting a strong negative minimum at S = 6, corresponding to the maximum in the cmc values. For the mixed system of oppositely charged surfactants (C 12 C S C 12 Br 2 ( S = 2, 6, 10)/NaCA), we did obtain from ITC the critical parameters for different events that take place as the concentration of gemini surfactant increases, such as the formation of NaCA-rich mixed micelles (cmc mix , Δ H mic-mix ), the formation of a precipitate (immiscible liquid crystalline (LC) phase) ( C P , Δ H P ) and its re-dissolution ( C R , Δ H R ), and finally the formation of positive charge-rich mixed micelles ( C M , Δ H M ). It should be stressed that the values of cmc mix (gemini) are much smaller than those for pure gemini and pure NaCA. These results also show that there is a stronger synergistic effect between the two surfactants in the NaCA-rich region. The turbidity measurements proved valuable to the determination of the region of immiscible LC phase. The ITC results are combined with those obtained by conductivity and turbidity leading to a thorough discussion of the effect of the gemini spacer length on the aggregation behavior of the mixed systems.
研究领域:
物理化学
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胶体与界面科学
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DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2022
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IF 5.518
Xu Xu,Chaonan Jiao,Hao Yang,Hao Chen,Jing Wang
Au NPs generated in situ by photochemical reduction method were used as catalysts for the oxidation of sodium cholate . The circular dichroism of the oxidation product of sodium cholate exhibits a positive Cotton effect at 335 nm and an intense negative Cotton effect at 281 nm. Electrospray ionization (ESI) mass spectra and nuclear magnetic resonance (NMR) spectra were performed to characterize the chemical composition of the oxidation product of sodium cholate, revealing that two of the hydroxyl groups were selectively oxidized to oxo groups and the oxidation product is 12-hydroxy-3,7-diketo-cholanic acid (3,7-DKCA). The chiral recognition abilities of the aggregates of 3,7-DKCA were investigated by using planar chiral molecules R- and S-binaphthyl compounds. Compared with sodium cholate, the aggregates of 3,7-DKCA displayed higher chiral selective host–guest binding to the model molecules and the chiral recognition mechanism was clarified.
研究领域:
生物化学
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纳米医学
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分析化学
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2016
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IF 5.31
Yilin Wu,Chen Wang,Juan Zhao,Jiuyun Cui,Yongsheng Yan,Chunxiang Li
Development of nanocomposites with environmentally response-type affinity sites, which can rapidly change the recognition rates in response to external, noninvasive stimuli, has broad technological applications for areas. In this work, inspired by a polydopamine (pDA) self-assembly strategy, a well-defined optically and thermally responsive silica/MIPs/gold nanocomposite (TO-MIPs) was successfully synthesized for the selective recognition and separation of sodium cholate hydrate (SCH). The design and engineering of these smart materials was achieved through the coupling of pDA-modified SiO 2 surfaces with poly(N-isopropyl acrylamide) (PNIPAm)-based SCH-imprinted layers that can change their physical conformation in response to heat. The TO-MIPs were finally synthesized by being coupled with Au nanoparticles (the sensitive light-heat converter) through an in situ reduction of metallic salts. Importantly, largely enhanced rebinding capacity (37.87 mg/g) and regeneration performance were both achieved. Moreover, with the opto-thermally responsive ‘specific recognition sites’, the as-prepared TO-MIPs not only exhibited rapid specific adsorption dynamics, but also possessed opto-thermally responsive separation performance of SCH. This biologically inspired methodology processed high durability and regeneration performance and was capable of reversibly controlling specific binding capacities of SCH from 11.76 to 35.79 mg/g in less than 5 min using the noninvasive stimulus of light. Additionally, the whole synthesis procedures were conducted in aqueous solution at low temperature, which are environmental friendly for scaling up without pollution.
研究领域:
材料科学
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生物医学工程
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纳米技术
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产品关联
DOI
高影响因子
CELLULOSE
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2020
·Vol. 27
·期 7
·4019-4028
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IF 4.21
Shen Junyan,Yang Xiaogang,Sun Xiaoqing,Gong Wenli,Ma Yanan,Liu Lin,Yao Juming
In this work, a novel and high-efficiency scavenger based on amino-functionalized cellulose was designed for sodium cholate sorption in vitro. To estimate the adsorption performance of the amino-functionalized cellulose for sodium cholate, various factors including sodium cholate concentration, contact time and electrolyte were investigated. The results suggested that amino-functionalization for cellulose regarding to hyperbranched polyethylenimine not only induce positive charge surface of cellulose but also provide abundant and special binding sites for sodium cholate sorption. The amino-functionalized cellulose displayed an excellent performance to sodium cholate sorption with a maximum adsorption capacity of 569.7 mg/g, higher than cholestyramine, a synthetic lipid-lowering drug in clinic. And the adsorption behavior was well fitted into the Langmuir isotherm model and pseudo-second-order kinetic model, suggesting a homogeneous monolayer chemisorption. Furthermore, the amino-functionalized cellulose presented the features of excellent anti-interferences, cytocompatibility and facile preparation process. All these results support amino-functionalized cellulose as a promising prospect for cholesterol elimination.
研究领域:
生物医学工程
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材料科学
✓ 已验证
DOI
高影响因子
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