Charge- and size-based separation of macromolecules using ultrathin silicon membranes
Charge- and size-based separation of macromolecules using ultrathin silicon membranes
复制标题
DOI：
10.1038/nature05532
复制
发表时间：
2007-02-15
期刊：
影响因子：
64.8
通讯作者：
Fauchet, Philippe M.
中科院分区：
文献类型：
--
作者：
Striemer, Christopher C.;Gaborski, Thomas R.;Fauchet, Philippe M.
商业超滤和透析膜具有宽的孔径分布，并且比它们被设计用于分离的分子厚1，000倍以上，导致差的尺寸截止特性、膜内的滤液损失和低的传输速率（1，2）。纳米制造的膜通过提供更精确的结构控制（3，4）在分子分离应用中具有巨大的潜力，但传输也受到微米级厚度的限制（5）。这种限制可以通过一类新的纳米结构膜来解决，其中膜的厚度与被分离的分子大致相同（类似于10 nm），但膜的脆弱性和复杂的制造阻止了纳米结构膜用于分子分离（1）。在这里，我们报告的开发的多孔纳米晶硅（pnc-Si）膜使用简单的硅制造技术，提供控制平均孔径从约5 nm至25 nm。我们的pnc-Si膜可以保留蛋白质，同时允许以比现有材料快一个数量级的速率运输小分子，在生理条件下分离不同大小的蛋白质，并分离携带不同电荷的类似大小的分子。尽管只有15 nm厚，但自立式超过40，000 μ m（2）的pnc-Si膜可以支持全大气压的压差，而不会发生塑性变形或断裂。通过提供高效、低损失的大分子分离，pnc-Si膜有望实现各种新设备，包括基于膜的色谱系统以及需要高效分离的分析和制备微流体系统。
Commercial ultrafiltration and dialysis membranes have broad pore size distributions and are over 1,000 times thicker than the molecules they are designed to separate, leading to poor size cutoff properties, filtrate loss within the membranes, and low transport rates(1,2). Nanofabricated membranes have great potential in molecular separation applications by offering more precise structural control(3,4), yet transport is also limited by micrometre-scale thicknesses(5). This limitation can be addressed by a new class of ultrathin nanostructured membranes where the membrane is roughly as thick (similar to 10 nm) as the molecules being separated, but membrane fragility and complex fabrication have prevented the use of ultrathin membranes for molecular separations(1). Here we report the development of an ultrathin porous nanocrystalline silicon (pnc-Si) membrane using straightforward silicon fabrication techniques that provide control over average pore sizes from approximately 5 nm to 25 nm. Our pnc-Si membranes can retain proteins while permitting the transport of small molecules at rates an order of magnitude faster than existing materials, separate differently sized proteins under physiological conditions, and separate similarly sized molecules carrying different charges. Despite being only 15 nm thick, pnc-Si membranes that are free-standing over 40,000 mu m(2) can support a full atmosphere of differential pressure without plastic deformation or fracture. By providing efficient, low-loss macromolecule separations, pnc-Si membranes are expected to enable a variety of new devices, including membrane-based chromatography systems and both analytical and preparative microfluidic systems that require highly efficient separations.