Photos Peter J, Bermudez Harry, Aranda-Espinoza Helim, Shillcock Julian, Discher Dennis E
Laboratory for Research on the Structure of Matter, University of Pennsylvania, Philadelphia, Pennsylvania 19104.
Soft Matter. 2007 Feb 14;3(3):364-371. doi: 10.1039/b611412c.
The lumen of the nuclear pore complex is increasingly understood to be lined by a polymer brush that entropically regulates transport in and out of the nucleus-and it seems likely that similar effects probably arise with glycocalyx-lined holes in cell membranes. Here we mimic such pore-confined brushes with self-assembled polymer membranes imbued with nano-holes. Experiment and theory help elucidate the entropic origin and stabilization of the pores, which appear to have a similar basis as steric stabilization of colloids bearing polymer brushes. Free energies of interacting brushes reveal stable minima at pore sizes smaller than the classical metastable point, with little effect of the particular pore geometry. Such entropic forces have potential implications for lock and key mechanisms of nuclear pore assembly as well as transient poration of cells and synthetic nano-pores with regulatory mechanisms for transport.
人们越来越认识到，核孔复合体的内腔由聚合物刷排列，该聚合物刷通过熵调节进出细胞核的运输——并且细胞膜中由糖萼排列的孔可能也会产生类似的效应。在这里，我们用充满纳米孔的自组装聚合物膜模拟这种孔限制刷。实验和理论有助于阐明孔的熵起源和稳定性，其似乎与带有聚合物刷的胶体的空间稳定具有相似的基础。相互作用刷的自由能在小于经典亚稳点的孔径处显示出稳定的最小值，特定孔几何形状的影响很小。这种熵力对核孔组装的锁钥机制以及细胞和合成纳米孔的瞬时穿孔及其运输调节机制具有潜在影响。
