Castle J D, Hubbell W L
Biochemistry. 1976 Nov 2;15(22):4818-31. doi: 10.1021/bi00667a011.
The distribution of a paramagnetic amphiphile, N,N-dimethyl-N-nonyl-N-tempoylammonium ion, between the membranes of charged phospholipid vesicles and the surrounding aqueous medium was studied by electron paramagnetic resonance spectroscopy. By systematically varying the surface charge of the vesicles and the aqueous electrolyte concentration, the distribution was shown to indicate vesicle surface potential. At each fixed phospholipid composition, the surface potential exhibited a dependence on aqueous NaCl concentration very similar to that predicted by the Gouy equation. The ability to sense and quantitate surface potentials makes this facile and sensitive technique of value in the study of cell and organelle surfaces.
通过电子顺磁共振光谱研究了顺磁性两亲物N,N-二甲基-N-壬基-N-特戊酰铵离子在带电磷脂囊泡膜与周围水相介质之间的分布。通过系统地改变囊泡的表面电荷和水相电解质浓度，发现该分布表明了囊泡表面电位。在每种固定的磷脂组成下，表面电位对NaCl水相浓度的依赖性与古依方程预测的非常相似。这种感知和定量表面电位的能力使得这种简便而灵敏的技术在细胞和细胞器表面研究中具有价值。
