1] School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA [2] Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, Massachusetts 02138, USA.
School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA.
Nature. 2015 Mar 5;519(7541):70-3. doi: 10.1038/nature14253.
Living organisms make extensive use of micro- and nanometre-sized pores as gatekeepers for controlling the movement of fluids, vapours and solids between complex environments. The ability of such pores to coordinate multiphase transport, in a highly selective and subtly triggered fashion and without clogging, has inspired interest in synthetic gated pores for applications ranging from fluid processing to 3D printing and lab-on-chip systems. But although specific gating and transport behaviours have been realized by precisely tailoring pore surface chemistries and pore geometries, a single system capable of controlling complex, selective multiphase transport has remained a distant prospect, and fouling is nearly inevitable. Here we introduce a gating mechanism that uses a capillary-stabilized liquid as a reversible, reconfigurable gate that fills and seals pores in the closed state, and creates a non-fouling, liquid-lined pore in the open state. Theoretical modelling and experiments demonstrate that for each transport substance, the gating threshold-the pressure needed to open the pores-can be rationally tuned over a wide pressure range. This enables us to realize in one system differential response profiles for a variety of liquids and gases, even letting liquids flow through the pore while preventing gas from escaping. These capabilities allow us to dynamically modulate gas-liquid sorting in a microfluidic flow and to separate a three-phase air-water-oil mixture, with the liquid lining ensuring sustained antifouling behaviour. Because the liquid gating strategy enables efficient long-term operation and can be applied to a variety of pore structures and membrane materials, and to micro- as well as macroscale fluid systems, we expect it to prove useful in a wide range of applications.
生物体广泛利用微纳尺寸的孔作为调控复杂环境中流体、蒸汽和固体传输的门控。这些孔能够以高度选择性和微妙触发的方式协调多相传输，而不会堵塞，这激发了人们对合成门控孔的兴趣，其应用范围从流体处理到 3D 打印和芯片实验室系统。但是，尽管通过精确调整孔表面化学和孔几何形状已经实现了特定的门控和传输行为，但仍然难以实现能够控制复杂、选择性多相传输的单一系统，而且堵塞几乎是不可避免的。在这里，我们引入了一种使用毛细稳定液体作为可逆、可重构门的门控机制，该门在关闭状态下填充和密封孔，在打开状态下形成无堵塞、液体衬里的孔。理论建模和实验表明，对于每种传输物质，门控阈值（打开孔所需的压力）可以在很宽的压力范围内进行合理调节。这使我们能够在一个系统中实现各种液体和气体的差分响应轮廓，甚至可以让液体流过孔而防止气体逸出。这些功能使我们能够在微流中动态调节气液分拣，并分离三相空气-水-油混合物，液体衬里确保了持续的防污性能。由于液体门控策略能够实现高效的长期运行，并且可以应用于各种孔结构和膜材料，以及微尺度和宏观尺度的流体系统，我们预计它将在广泛的应用中证明是有用的。
