INQUIMAE-CONICET and DQIAQF-School of Sciences-University of Buenos Aires, Ciudad Universitaria, Pabellón 2, Ciudad Autónoma de Buenos Aires, C1428EHA, Argentina.
J Phys Condens Matter. 2018 Jul 11;30(27):274006. doi: 10.1088/1361-648X/aac90b. Epub 2018 May 31.
This work presents a theoretical study of the translocation routes of nanoparticles through polymer-brush modified nanopores. The calculations were performed with a molecular theory that explicitly accounts for the shape, size, conformations and interactions of all molecular species in the system. This work reports molecular-theory calculations allowing inhomogeneities in the three spatial dimensions, which allows us to study for the first time off-axis translocation routes, i.e. routes that do not coincide with the axis of the pore. Free-energy landscapes within the pore were obtained for particles of different sizes and affinity for the polymer brush. The minimum free-energy paths on these landscapes determine the translocation routes. Decreasing the size of the particle or increasing its affinity for the polymer, shifts the translocation route from the central axis of the pore towards its walls. Interestingly, for a given polymer-particle affinity, there exists an intermediate particle size that results in the most flat potential of mean force for translocation, therefore, that will optimize the rate of translocation.
这项工作提出了一个理论研究，纳米颗粒通过聚合物刷修饰的纳米孔的易位途径。计算是用一种分子理论进行的，该理论明确考虑了系统中所有分子种类的形状、大小、构象和相互作用。这项工作报告了分子理论计算，允许在三个空间维度上存在不均匀性，这使我们能够首次研究偏离轴的易位途径，即与孔轴不重合的途径。对于不同大小和对聚合物刷亲和力的颗粒，在孔内获得了自由能景观。这些景观上的最小自由能路径决定了易位途径。减小颗粒的尺寸或增加其对聚合物的亲和力，将易位途径从孔的中心轴移向其壁。有趣的是，对于给定的聚合物-颗粒亲和力，存在一个中间颗粒尺寸，导致易位的平均力势最平坦，因此，将优化易位的速率。
