Versatile ultrathin nanoporous silicon nitride membranes
Versatile ultrathin nanoporous silicon nitride membranes
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DOI：
10.1073/pnas.0911450106
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发表时间：
2009-12-15
影响因子：
11.1
通讯作者：
Siwy, Zuzanna S.
中科院分区：
文献类型：
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作者：
Vlassiouk, Ivan;Apel, Pavel Y.;Siwy, Zuzanna S.
单纳米孔和多纳米孔膜对于生物传感和分离过程以及它们模拟生物膜的能力都非常有趣。孔的密度、孔的形状和表面化学性质是决定膜运输和分离能力的关键因素。在这里，我们报道了氮化硅（SiN）膜具有完全可控的孔隙率，孔隙几何形状和孔隙表面化学。描述了一种超薄的独立SiN平台，其直径小至几纳米的锥形或双锥形纳米孔是通过轨迹蚀刻技术制备的。这项技术允许膜孔隙度从每平方厘米一个孔调整到数十亿个孔。我们证明了这些膜的分离能力，通过区分染料和蛋白质分子基于他们的电荷和大小。这种分离过程基于静电机制，并在生理电解质条件下进行。正如我们所展示的，分离能力可以通过化学修饰孔壁来调节。与典型的圆柱形孔膜相比，本文报道的锥形孔和双锥形孔允许更高的通量，这是分离应用的关键优势。此外，锥形孔的有效长度较短，这为单生物分子检测应用（如基于纳米孔的DNA分析）提供了优势。
Single-and multiple-nanopore membranes are both highly interesting for biosensing and separation processes, as well as their ability to mimic biological membranes. The density of pores, their shape, and their surface chemistry are the key factors that determine membrane transport and separation capabilities. Here, we report silicon nitride (SiN) membranes with fully controlled porosity, pore geometry, and pore surface chemistry. An ultrathin freestanding SiN platform is described with conical or double-conical nanopores of diameters as small as several nanometers, prepared by the track-etching technique. This technique allows the membrane porosity to be tuned from one to billions of pores per square centimeter. We demonstrate the separation capabilities of these membranes by discrimination of dye and protein molecules based on their charge and size. This separation process is based on an electrostatic mechanism and operates in physiological electrolyte conditions. As we have also shown, the separation capabilities can be tuned by chemically modifying the pore walls. Compared with typical membranes with cylindrical pores, the conical and double-conical pores reported here allow for higher fluxes, a critical advantage in separation applications. In addition, the conical pore shape results in a shorter effective length, which gives advantages for single biomolecule detection applications such as nanopore-based DNA analysis.