From vesicle size distributions to bilayer elasticity via cryo-transmission and freeze-fracture electron microscopy

被引:82
作者
Coldren, B
van Zanten, R
Mackel, MJ
Zasadzinski, JA [1 ]
Jung, HT
机构
[1] Univ Calif Santa Barbara, Dept Chem Engn, Santa Barbara, CA 93106 USA
[2] Univ Calif Santa Barbara, Mat Res Lab, Santa Barbara, CA 93106 USA
[3] Korea Adv Inst Sci & Technol, Dept Chem & Biochem Engn, Taejon 305701, South Korea
关键词
D O I
10.1021/la034311+
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
Three methods of evaluating vesicle mean radii and polydispersity, quasi-elastic light scattering (QLS), freeze-fracture electron microscopy (FF-TEM), and cryo-transmission electron microscopy (cryo-TEM), were used to determine the size distributions of spontaneous vesicles made from mixtures of cetyltrimethylammonium tosylate (CTAT) and sodium dodecylbenzene sulfonate (SDBS). While QLS is probably the most commonly used method to size vesicles, it is limited to measures of the mean hydrodynamic radius and an estimate of the polydispersity, both of which are heavily weighted toward the largest structures in the solution. Cryo-TEM can provide the entire size distribution of the outer diameters of spherical vesicles, from which the sum of the Helfrich bilayer elastic parameters, K = kappa + (kappa) over bar /2 and the spontaneous curvature radius, R-0, can be determined. FF-TEM can provide the number-average mean diameter and polydispersity once the influence of the fracture plane has been factored into the distribution, thereby confirming the cryo-TEM size distribution. For 7:3 wt CTAT/SDBS at 1% total surfactant in water, K = kappa + (kappa) over bar /2 = 0.15 +/- 0.03 k(B)T and R-0 = 55 nm +/- 10 nm. For CTAT/SDBS, w/w, at 2% total surfactant, K = 0.54 kT +/- 0.05 k(B)T and R-0 = 36 nm +/- 1 nm. We find that surfactant mixing is likely the origin of the low bilayer elasticity in catanionic vesicles. However, the lower value of K in the CTAT-rich sample is likely due to the hydrophobic tosylate counterion increasing the area per headgroup.
引用
收藏
页码:5632 / 5639
页数:8
相关论文
共 41 条
[32]  
MCKELVEY CA, UNPUB LANGMUIR
[33]   Statistical mechanics of closed fluid membranes [J].
Morse, DC ;
Milner, ST .
PHYSICAL REVIEW E, 1995, 52 (06) :5918-5945
[34]  
Safran S. A., 2018, Statistical Thermodynamics of Surfaces, Interfaces, and Membranes
[35]   STABILITY AND PHASE-BEHAVIOR OF MIXED SURFACTANT VESICLES [J].
SAFRAN, SA ;
PINCUS, PA ;
ANDELMAN, D ;
MACKINTOSH, FC .
PHYSICAL REVIEW A, 1991, 43 (02) :1071-1078
[36]   THEORY OF SPONTANEOUS VESICLE FORMATION IN SURFACTANT MIXTURES [J].
SAFRAN, SA ;
PINCUS, P ;
ANDELMAN, D .
SCIENCE, 1990, 248 (4953) :354-356
[37]  
SIMONS BD, 1992, J PHYS II, V2, P1439
[38]   CHAIN PACKING STATISTICS AND THERMODYNAMICS OF AMPHIPHILE MONOLAYERS [J].
SZLEIFER, I ;
BENSHAUL, A ;
GELBART, WM .
JOURNAL OF PHYSICAL CHEMISTRY, 1990, 94 (12) :5081-5089
[39]  
SZLEIFER I, 1990, J CHEM PHYS, V92, P5081
[40]   Phase behavior of aqueous mixtures of cetyltrimethylammonium bromide (CTAB) and sodium octyl sulfate (SOS) [J].
Yatcilla, MT ;
Herrington, KL ;
Brasher, LL ;
Kaler, EW ;
Chiruvolu, S ;
Zasadzinski, JA .
JOURNAL OF PHYSICAL CHEMISTRY, 1996, 100 (14) :5874-5879