Hydrophobic Gating in Membrane Nanopores: Water at the Nanoscale

水的性质在生物学中起着关键作用，是细胞结构和功能的所有方面的基础。所有细胞都被细胞膜所包围，细胞膜上存在孔样蛋白，这些蛋白允许细胞内外之间的交流和交换。这样的纳米级孔（“纳米孔”）在细胞生物物理学和作为新型生物传感器的潜在组分两者中都非常重要。纳米孔充满了水。然而，水在纳米尺度上的行为不同，在直径为人类头发直径的百万分之一的孔隙内。特别是，如果纳米孔的衬里足够疏水（即“油性”），则纳米孔可能会发生自发去湿。这提供了一种可能的方法，其中控制纳米孔的活性，如果我们可以控制它们的润湿/去湿。因此，我们需要理解并能够模拟润湿和去湿的物理化学基础，其准确度足以预测，以帮助设计新的纳米孔。这可以通过计算机模拟来实现-结合先进的算法和现代超级计算机的能力。通过这种方式，我们将确定纳米孔中的水的行为，了解它们如何通过润湿和去湿功能性地“打开和关闭”，以及在含纳米孔的膜上施加电压差如何导致纳米孔电润湿，从而将它们从非活性（关闭）状态切换到活性（打开）状态。这项基础研究将使我们能够设计用于生物传感器和其他医疗保健相关应用的新纳米孔的可控打开/关闭。

The properties of water play a key role in biology, underlying all aspects of cellular structure and function. All cells are surrounded by lipidic membranes, in which there exist pore-like proteins which allow communication and exchange between the inside and outside of cells. Such nanoscale pores ('nanopores') are of great importance both in cell biophysics and as potential components of novel biosensors. Nanopores are filled with water. However, water behaves differently on the nanoscale, inside pores whose diameter is 10 millionths of diameter that of a human hair. In particular, nanopores can undergo spontaneous de-wetting if their lining is sufficiently hydrophobic (i.e. 'oily'). This provides a possible way in which to control the activity of nanopores if we can control their wetting/de-wetting.We consequently need to understand and be able to model the physicochemical basis of wetting and de-wetting at a level of accuracy good enough for predictions to aid design of novel nanopores. This can be achieved by computer simulations - combining advanced algorithms and the power of modern supercomputers.In this way, we will determine the behaviour of water in nanopores, understanding how they can be functionally 'opened and closed' by wetting and de-wetting, and how the imposition of a voltage difference across a nanopore-containing membrane can cause the nanopores to electrowet, thereby switching them from an inactive (closed) to an active (open) state.This fundamental research will allow us to design controllable opening/closing of new nanopores for use in biosensors and other healthcare related applications.