Elevated levels of the essential trace metals cobalt and nickel are associated with a variety of toxic effects, which are not well-understood, and may involve interactions with the lipid membrane. Fluidity changes of biomimetic lipid membranes upon exposure to CoCl₂ and NiCl₂ were studied using the fluorescent probe Laurdan, which senses changes in environment polarity. Liposomes were prepared by extrusion in 20 mM HEPES + 100 mM NaCl at pH 7.4. Additionally, dynamic light scattering was used to monitor metal induced size changes of liposomes composed of: phosphatidic acid (PA), cardiolipin (CL), phosphatidylglycerol (PG), phosphatidylserine (PS), and phosphatidylcholine (PC), with saturated and unsaturated acyl chains. Micromolar concentrations of both metals significantly rigidify negatively-charged liposomes and generally increase the melting temperature. Saturated acyl chains showed stronger metal effects in PS and PG, while no clear acyl chain preference was observed in CL and PA systems. The strength of the effect appears to be influenced greatly by both the head group and acyl chain. The rigidifying effects of cobalt were almost always much larger than those of nickel. In addition, size changes and aggregation by both metals was detected in PS or PA liposomes at molar metal/lipid ratios as low as 1/10.

必需的痕量金属钴和镍的含量升高与多种毒性作用有关，这些作用尚未得到很好的理解，并且可能涉及与脂质膜的相互作用。暴露于CoCl ₂和NiCl ₂的仿生脂质膜的流动性变化我们使用感应环境极性变化的荧光探针Laurdan进行了研究。通过在pH 7.4的20 mM HEPES + 100 mM NaCl中挤出制备脂质体。此外，动态光散射用于监测脂质体的金属诱导的尺寸变化，该脂质体由以下组成：磷脂酸（PA），心磷脂（CL），磷脂酰甘油（PG），磷脂酰丝氨酸（PS）和磷脂酰胆碱（PC），以及饱和和不饱和酰基链。两种金属的微摩尔浓度可显着使带负电的脂质体刚性化，并通常会提高解链温度。饱和的酰基链在PS和PG中表现出较强的金属效应，而在CL和PA系统中未观察到明显的酰基链偏好。效果的强度似乎受头基和酰基链的影响很大。钴的刚性作用几乎总是比镍大得多。此外，在PS或PA脂质体中，金属/脂质的摩尔比低至1/10，检测到两种金属的尺寸变化和聚集。