Charge and size based filtration by ultrathin silicon membranes

描述（由申请人提供）：这项工作将研究纳米多孔硅膜（pnc-Si）的潜力，基于它们的大小和电荷来提供革命性的大分子过滤。由于这种新型膜材料的分子薄（15 nm），预计它将提高基于扩散和对流流的分离效率。因为这种材料是由硅制成的，制造是可扩展的，很容易集成到微流体装置中，并且易于表面修饰，可以通过外部控制的电压来控制膜的渗透率。该材料可使许多小型分析、制备和治疗装置成为可能。目的1：定量表征pnc-Si膜在扩散基分离中的性能，我们将量化pnc-Si膜在扩散基分离中的功能。使用具有一系列孔隙率和孔径的膜库，我们将确定：1)模型物种和蛋白质混合物的排斥大小；2)小溶质、模型粒子和蛋白质通过pnc-Si膜的迁移性。工作将通过测量在存在和不存在高浓度蛋白质的情况下的小溶质运输，直接解决蛋白质吸附的潜在有害影响。膜将通过透射电子显微镜直接检查生物污染的证据。如果蛋白质吸附减缓运输，膜将通过接枝短PEG分子进行修饰，并且修饰后的膜重新表征。目的2：定量表征pnc-Si膜的电荷基分离在这里，我们将表征pnc-Si膜分离大分子基于电荷的能力。我们将测量带电染料在不同离子强度溶液中的扩散输运。我们将使用制备好的膜和我们修改的带永久负电荷或正电荷的膜来量化结果，结果将在德拜-哈克理论的背景下解释。然后，我们将通过调节白蛋白等电点周围的溶液pH值来研究膜电荷对蛋白质运输的重要性。最后，将在pnc-Si膜上涂覆贵金属，目的是通过外部控制膜电荷来主动调节膜的通透性。该项目将描述一种新型硅基纳米孔膜根据大小和电荷选择性过滤大分子的能力。分子薄的纳米膜有可能彻底改变过滤速度，并且是第一种可以作为模块集成到微流体系统中的过滤材料。这些能力有望使一系列新的小型临床和诊断设备成为可能。

DESCRIPTION (provided by applicant): This work will investigate the potential of a nanoporous silicon membrane (pnc-Si) to provide revolutionary filtration of macromolecules based on their size and charge. Because the novel membrane material is molecularly thin (15 nm), it is predicted to improve the efficiency of both diffusion and convective flow based separations. Because the material is made from silicon, manufacturing is scalable, readily integrated into microfluidic devices, and amenable to surface modifications could make membrane permeability controllable through an externally controlled voltage. The material may enable a host of small scale analytical, preparative and therapeutic devices. Aim 1: Quantitatively characterize the performance of pnc-Si membranes for diffusion- based separations we will quantify the function of pnc-Si membranes in diffusion-based separations. Using a membrane library with a range of porosities and pore sizes, we will determine: 1) rejection sizes of model species and protein mixtures; and 2) the mobility of small solutes, model particles, and proteins through pnc-Si membranes. Work will directly address the potential deleterious effects of protein adsorption by measuring small solute transport in the presence and absence of high protein concentrations. Membranes will be directly inspected for evidence of bio-fouling by transmission electron microscopy. If protein adsorption slows transport, membranes will be modified by grafting with short PEG molecules, and the modified membranes re-characterized. Aim 2: Quantitatively characterize pnc-Si membranes for charged-based separations Here we will characterize the ability of pnc-Si membranes to separate macromolecules based on charge. We will measure diffusive transport of charged dyes in solutions of different ionic strength. We will quantify results using as-prepared membranes and membranes that we modify to carry permanent negative or positive charge, Results will be interpreted in the context of Debye-Huckel theory. We will then examine the importance of membrane charge on protein transport by modulating solution pH around the isoelectric point of albumin. Finally, will coat pnc-Si membranes with noble metals with the goal of actively adjusting membrane permeability through external control over membrane charge. This project will characterize the ability of a new silicon-based, nanoporous membrane to selectively filter macromolecules based on size and charge. The molecularly thin nanomembranes have the potential to revolutionize filtration rates and are the first filter material that can be integrated into microfluid systems as modules. These abilities are expected to enable a host of new small scale clinical and diagnostic devices.