Diatom nanopore membrane devices for molecular transport and biomembrane studies

智能优点：纳米孔膜已成为过滤不可或缺的工具。然而，这些膜具有若干缺点。为了实现分子分离，纳米孔必须具有与分子相同的尺寸。如果要保持机械稳定性，这种小的纳米孔将非常长，显著减慢分子运输。使用电子束或离子束光刻在二氧化硅或氮化硅膜中图案化的纳米孔具有具有良好控制的尺寸的益处，并且可以控制厚度，但是它们的制造成本高。生物矿化的结构，如二氧化硅硅藻壳，提供了一种替代的方法对纳米孔膜。一些物种表现出40 nm量级的纳米孔的窄尺寸分布，而它们的直径可以生长到200 µm。硅藻壳具有分级孔结构，稳定具有两组较大孔的纳米孔膜。由于它们由二氧化硅组成，因此它们是光学透明的，并且可以使用硅烷化学进行官能化。 在拟议的项目中，将探索使用二氧化硅硅藻壳作为微器件中的纳米膜的可能性。使用二氧化硅表面的化学预图案化，硅藻壳将在晶片级上与预定义的结构对准，从而允许联合收割机组合自下而上和自上而下的器件架构。通过化学官能化二氧化硅纳米孔表面，例如使用原子层沉积，可以定制通过纳米孔的分子传输性质，从而允许分子分离研究。此外，这些孔本身可以作为所谓的纳米双层脂质膜的支撑结构，这种膜显示出自上而下的氮化硅纳米孔的寿命增加了30倍。更广泛的影响：这项研究将在纳米流体设备领域产生巨大的影响，最终取代目前用于过滤的轨道蚀刻纳米孔膜。由于孔尺寸小且孔长度短而不损害机械稳定性，因此预期分子的更快扩散。纳米双层脂质膜的预期寿命改善将对场离子通道重建产生变革性影响。 跨学科计划的目标是招募和留住优秀学生以及代表性不足和少数民族学生。研究生将接受教育，通过让他们参与拟议的研究活动，为未来的挑战做好准备，成为未来的工程师。本科生将通过已在亚利桑那州立大学建立的本科生研究计划奖学金计划参与。在与脚踏实地的科学（DES），在亚利桑那州州立大学的一个NSF资助的GK-12轨道II项目的合作，拟议的项目将提供一个新的教育机会，教师和研究生分享他们的研究成果与K-12社区，提供了一个新的推力，通过在纳米技术的前沿研究整合到中学课程。 研究部分将与评估计划相联系，从而能够对教育影响的有效性进行反馈，从而能够改进最初的教学概念。

Intellectual Merit: Nanopore membranes have become indispensible tools for filtration. However, these membranes have several drawbacks. To accomplish molecular separation, the nanopores have to be of the same size as the molecules. If mechanical stability is to be maintained, such small nanopores will be very long, significantly slowing down molecular transport. Nanopores patterned using electron or ion beam lithography in silicon dioxide or silicon nitride membranes have the benefit of having a well-controlled size and can be controlled in thickness, however they are costly to manufacture. Biomineralized structures, such as silica diatom shells, offer an alternative approach towards nanopore membranes. Some species exhibit a narrow size distribution of nanopores on the order of 40 nm while they can grow up to 200 µm in diameter. Diatom shells have a hierarchical pore structure, stabilizing the nanopore membrane with two sets of larger pores. Since they consist of silica, they are optically transparent and can be functionalized using silane chemistry. In the proposed project the possibility of using the silica diatom shells as nanomembranes in microdevices will be explored. Using chemical pre-patterning of silicon dioxide surfaces the diatom shells will be aligned to pre-defined structures on a wafer scale, allowing to combine bottom-up and top-down device architectures. By chemically functionalizing the silica nanopore surface, for example using Atomic Layer Deposition, the molecular transport properties through the nanopores can be tailored, allowing molecular separation studies. Furthermore, the pores themselves can act as support structures for so-called nano-Bilayer Lipid Membranes, which show an increase in lifetime by a factor of 30 on top-down silicon nitride nanopores.Broader Impact:The research will have a tremendous impact in the field of nanofluidic devices, eventually replacing the track-etched nanopore membranes that are currently used for filtration. Since the pore sizes are small and the pore length is short without compromising the mechanical stability, faster diffusion of molecules is expected. The expected lifetime improvement of nano-Bilayer Lipid Membranes will have a transformational impact on the field ion channel reconstitution. The interdisciplinary program targets to recruit and retain highly talented students as well as underrepresented and minority students. Graduate students will be educated to become future engineers by preparing them for the challenges that lie ahead by involving them in the proposed research activities. Undergraduate students will be engaged via the Undergraduate Research Initiative scholarship program that has been established at ASU. In collaboration with the Down-to-Earth Science (DES), an NSF-funded GK-12 track II project at Arizona State University, the proposed project will offer a novel educational opportunity for faculty and graduate students to share their research results with the K-12 community, providing a new thrust through the integration of cutting edge research in nanotechnology into the secondary school curriculum. The research component will be linked with an assessment plan, enabling feedback on the effectiveness of the educational impact, enabling an improvement of the initial teaching concepts.