Benet Jorge, Paillusson Fabien, Kusumaatmaja Halim
Department of Physics, Durham University, Durham, DH1 3LE, UK.
Phys Chem Chem Phys. 2017 Sep 13;19(35):24188-24196. doi: 10.1039/c7cp03874g.
Using a lattice model and a versatile thermodynamic integration scheme, we study the critical Casimir interactions between inclusions embedded in a two-dimensional critical binary mixtures. For single-domain inclusions we demonstrate that the interactions are very long range, and their magnitudes strongly depend on the affinity of the inclusions with the species in the binary mixtures, ranging from repulsive when two inclusions have opposing affinities to attractive when they have the same affinities. When one of the inclusions has no preference for either of the species, we find negligible critical Casimir interactions. For multiple-domain inclusions, mimicking the observations that membrane proteins often have several domains with varying affinities to the surrounding lipid species, the presence of domains with opposing affinities does not cancel the interactions altogether. Instead we can observe both attractive and repulsive interactions depending on their relative orientations. With increasing number of domains per inclusion, the range and magnitude of the effective interactions decrease in a similar fashion to those of electrostatic multipoles. Finally, clusters formed by multiple-domain inclusions can result in an effective affinity patterning due to the anisotropic character of the Casimir interactions between the building blocks.
使用晶格模型和通用的热力学积分方案，我们研究了嵌入二维临界二元混合物中的内含物之间的临界卡西米尔相互作用。对于单域内含物，我们证明相互作用具有很长的范围，并且它们的大小强烈依赖于内含物与二元混合物中物种的亲和力，范围从两个内含物具有相反亲和力时的排斥力到具有相同亲和力时的吸引力。当其中一个内含物对任何一种物种都没有偏好时，我们发现临界卡西米尔相互作用可以忽略不计。对于多域内含物，模仿膜蛋白通常具有几个对周围脂质物种具有不同亲和力的结构域的观察结果，具有相反亲和力的结构域的存在并不会完全消除相互作用。相反，根据它们的相对取向，我们可以观察到吸引力和排斥力相互作用。随着每个内含物结构域数量的增加，有效相互作用的范围和大小以与静电多极子类似的方式减小。最后，由于构建块之间卡西米尔相互作用的各向异性特征，由多域内含物形成的簇可以导致有效的亲和力图案化。
