Passive transport of C60 fullerenes through a lipid membrane:: A molecular dynamics simulation study
Passive transport of C60 fullerenes through a lipid membrane:: A molecular dynamics simulation study
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DOI：
10.1021/jp075149c
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发表时间：
2008-02-21
影响因子：
3.3
通讯作者：
Li, Liwei
中科院分区：
文献类型：
--
作者：
Bedrov, Dmitry;Smith, Grant D.;Li, Liwei
为了研究富勒烯的独特性质对其与脂质膜相互作用和被动转运的影响，我们对C-60富勒烯在完全水合的二肉豆肉酰基磷脂酰胆碱脂质膜中的原子分子动力学进行了模拟。在这些模拟中，得到了富勒烯的自由能和扩散率作为其在膜内位置的函数。这些性质被用来计算富勒烯通过脂质膜的通透性。模拟结果表明，当富勒烯从水相穿过头基层并进入疏水核心时，自由能降低。这种自由能的减少不是由于疏水相互作用，而是由于富勒烯和膜之间比富勒烯和（散装）水之间更强的范德华（分散）相互作用。研究发现，富勒烯从水相转运到膜的脂质核心没有自由能屏障。再加上富勒烯在膜的脂质核心上的强分配，这种“无障碍”渗透导致富勒烯通过脂质膜的渗透性惊人地大，比任何其他已知的渗透剂都要大。在模拟中，当富勒烯与其周围环境之间的分散相互作用强度降低，从而模拟纳米级疏水粒子时，出现了一个大的穿透头基层的自由能垒，这表明富勒烯通过脂质膜的大通透性是它们与周围介质独特相互作用的结果。
To investigate the implications of the unique properties of fullerenes on their interaction with and passive transport into lipid membranes, atomistic molecular dynamics simulations of a C-60 fullerene in a fully hydrated di-myristoyl-phoshatidylcholine lipid membrane have been carried out. In these simulations the free energy and the diffusivity of the fullerene were obtained as a function of its position within the membrane. These properties were utilized to calculate the permeability of fullerenes through the lipid membrane. Simulations reveal that the free energy decreases as the fullerene passes from the aqueous phase, through the head group layer and into the hydrophobic core of the membrane. This decrease in free energy is not due to hydrophobic interactions but rather to stronger van der Waals (dispersion) interactions between the fullerene and the membrane compared to those between the fullerene and (bulk) water. It was found that there is no free energy barrier for transport of a fullerene from the aqueous phase into the lipid core of the membrane. In combination with strong partitioning of the fullerenes into the lipidic core of the membrane, this "barrierless" penetration results in an astonishingly large permeability of fullerenes through the lipid membrane, greater than observed for any other known penetrant. When the strength of the dispersion interactions between the fullerene and its surroundings is reduced in the simulations, thereby emulating a nanometer sized hydrophobic particle, a large free energy barrier for penetration of the head group layer emerges, indicating that the large permeability of fullerenes through lipid membranes is a result of their unique interaction with their surrounding medium.