Institut für Nanostruktur- und Festkörperphysik (INF)/Center for Hybrid Nanostructures (CHyN), University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany.
Carl Zeiss Microscopy GmbH, Carl-Zeiss-Str. 22, 73447 Oberkochen, Germany.
Nanoscale. 2019 Jul 28;11(28):13620-13631. doi: 10.1039/c9nr02979f. Epub 2019 Jul 10.
We present micro- and nanofluidic devices with 3D structures and nanochannels with multiple depths for the analysis of single molecules of DNA. Interfacing the nanochannels with graded and 3D inlets allows the improvement of the flow and controls not only the translocation speed of the DNA but also its conformation inside the nanochannels. The complex, multilevel, multiscale fluidic circuits are patterned in a simple, two-minute imprinting step. The stamp, the key of the technology, is directly milled by focused ion beam, which allows patterning nanochannels with different cross sections and depths, together with 3D transient inlets, all at once. Having such a variety of structures integrated in the same sample allows studying, optimizing and directly comparing their effect on the DNA flow. Here, DNA translocation is studied in long (160 µm) and short (5-40 µm) nanochannels. We study the homogeneity of the stretched molecules in long, meander nanochannels made with this technology. In addition, we analyze the effect of the different types of inlet structures interfacing short nanochannels. We observe pre-stretching and an optimal flow, and no hairpin formation, when the inlets have gradually decreasing widths and depths. In contrast, when the nanochannels are faced with an abrupt transition, we observe clogging and hairpin formation. In addition, 3D inlets strongly decrease the DNA molecules' speed before they enter the nanochannels, and help capturing more DNA molecules. The robustness and versatility of this technology and DNA testing results evidence the potential of imprinted devices in biomedical applications as low cost, disposable lab-on-a-chip devices.
我们提出了具有 3D 结构和具有多个深度的纳米通道的微纳流控装置，用于分析单个 DNA 分子。将纳米通道与分级和 3D 入口相连接，可以改善流动，不仅控制 DNA 的迁移速度，还控制其在纳米通道内的构象。复杂的、多层次的、多尺度的流体回路在一个简单的、两分钟的压印步骤中进行图案化。压印模板，也就是该技术的关键，是直接通过聚焦离子束铣削而成，这允许同时对具有不同横截面和深度的纳米通道进行图案化，以及 3D 瞬变入口。在同一个样品中集成如此多种结构，可以研究、优化并直接比较它们对 DNA 流动的影响。在这里，在长（160 µm）和短（5-40 µm）纳米通道中研究 DNA 迁移。我们研究了用这种技术制造的长、蜿蜒纳米通道中伸展分子的均匀性。此外，我们分析了短纳米通道接口的不同类型入口结构的影响。我们观察到，当入口具有逐渐减小的宽度和深度时，存在预拉伸和最佳流动，而没有发夹形成。相比之下，当纳米通道面临突然的过渡时，我们观察到堵塞和发夹形成。此外，3D 入口强烈降低了 DNA 分子在进入纳米通道之前的速度，并有助于捕获更多的 DNA 分子。该技术的稳健性和多功能性以及 DNA 测试结果证明了压印设备在生物医学应用中的潜力，作为低成本、一次性的片上实验室设备。
