Molecular lithography with DNA nanostructures
Molecular lithography with DNA nanostructures
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DOI：
10.1002/anie.200460257
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发表时间：
2004-01-01
影响因子：
16.6
通讯作者：
Mao, CD
中科院分区：
文献类型：
--
作者：
Deng, ZX;Mao, CD
光刻的巨大成功源于其精确控制所产生图案的能力。另一种自下而上的方法来建立有序的自组装图案是有前途的，并可能取代传统的自上而下的光刻技术为基础的纳米级图案的制备。[1-9]在开发并行和自底向上技术的许多挑战中，控制图案形貌和缩小特征尺寸的能力是涉及其实际应用的两个中心问题。一个可能的解决方案是使用可调的、自组装的超分子结构作为光刻掩模; DNA纳米结构似乎是实现这一目的的理想材料。[10-16]在这里，我们证明DNA纳米结构可用作分子光刻的掩模。DNA纳米结构可以通过金属蒸发然后剥离掩模而精确地复制到金属纳米结构中。这种报道的技术的易用性和灵活性使其适合于生产定义和集成的纳米粒子，这代表了一种新的路线，以克服传统的光刻技术所面临的不确定性。DNA在其最初的遗传兴趣之外有许多应用。[7，8，10-20] DNA金属化以制造金属或纳米线是DNA双链体可以复制多长的一个例子。然而，金属化过程导致DNA分子的结构细节丢失。由此产生的纳米线至少比DNA模板厚10倍。[17-19]更严重的是，所得到的结构完全是线性结构，这与技术应用所需的结构复杂性相去甚远。DNA纳米技术的出现和迅速发展，使得通过自下而上的自组装构建复杂的DNA结构成为可能。由此产生的DNA结构已经被探索用于执行分子计算，[10]制作纳米机械设备，[13]和组织其他功能单元。[15这些DNA结构也将提供满足复杂性要求的理想手段。可以想象，具有设计的DNA结构的定义明确的纳米粒子可以作为直接复制的掩模。由于可以通过使用合适的分子/大分子作为掩模来克服当前光刻技术的特征尺寸限制，因此对该主题的研究可能对纳米科学和纳米技术产生根本性影响。我们报道的分子光刻方法是一种通用的并行方法。该工艺由四个步骤组成（图1），可以生成特征尺寸低至约10 nm的1D和2D金属纳米粒子。随着进一步的研究，这种方法有望在纳米尺度上制作具有高度可控形貌的功能电路、传感器和显示面板。我们组装DNA阵列，缓慢冷却等摩尔混合物的相应组件的DNA链从958 C到228 C，并将它们沉积到新鲜切割的云母基板。然后将20 nm厚的金膜热蒸发到云母基板上。在蒸发结束时，将一滴环氧混合物夹在金膜和载玻片之间并固化。然后将载玻片与金膜一起从云母表面分离。将接触DNA样品的一侧暴露于空气中，并含有DNA结构的阴性复制品。利用原子力显微镜（AFM）对DNA结构及其金属复制品进行了分析，首次揭示了原子力显微镜的原理。
The great success of photolithography results from its ability to accurately control the produced patterns. An alternative, bottom-up approach to build ordered patterns by selfassembly is promising and may supersede the traditional top-down lithography-based techniques for the preparation of nanoscaled patterns.[1–9] Among the many challenges in developing parallel and bottom-up techniques, the capabilities of controlling pattern topography and to scale-down feature dimensions are two central issues concerning their practical applications. One possible solution is to use tunable, self-assembled, supramolecular structures as lithography masks; DNA nanostructures appear to be ideal for this purpose.[10–16] Here we demonstrate that DNA nanostructures can be used as masks for molecular lithography. DNA nanostructures could be accurately replicated into metal nanostructures by metal evaporation followed by lifting off of the mask. The ease and flexibility of this reported technique make it suitable for producing defined and integrated nanopatterns, which represents a novel route to overcome the inabilities faced by traditional lithographic techniques. DNA has found many applications beyond its original genetic interest.[7, 8, 10–20] DNA metalization to fabricate metallic or semiconductive nanowires is one example of how long DNA duplexes can be replicated. However, the metalization process results in a loss of the structural details of the DNA molecules. The resulting nanowires are at least 10-times thicker than the DNA templates.[17–19] More seriously, the resulting structures are exclusively linear structures, which is far removed from the structural complexities required for technological applications. The emergence and fast development of DNA nanotechnology makes it possible to construct complicated DNA structures through bottom-up self-assembly of engineered DNA motifs. The resulting DNA structures have been explored for performing molecular computations,[10] crafting nanomechanical devices,[13] and organizing other functional units.[15, 20] These DNA structures would also provide an ideal means to meet the complexity requirement. It is conceivable that well-defined nanopatterns with designed DNA structures could be produced as masks for direct replication. Since it is possible to overcome the feature-size limitation of current lithographic techniques by the use of suitable molecules/macromolecules as masks, research on this topic may have fundamental influence on both nanoscience and nanotechnology. The molecular lithographic method we report here is a general and parallel method. The process consists of four steps (Figure 1), and can generate 1D and 2D metallic nanopatterns with feature sizes down to about 10 nm. With further elaborations, this method might be promising for making functional circuits, sensors, and display panels with highly controllable topography at the nanometer scale. We assembled DNA arrays by slowly cooling equimolar mixtures of the corresponding component DNA strands from 958C to 228C, and depositing them onto freshly cleaved mica substrates. A 20-nm-thick gold film was then thermally evaporated onto the mica substrate. At the end of the evaporation, a drop of epoxy mixture was sandwiched and solidified between the gold film and a glass slide. The glass slide together with the gold film was then separated from the mica surface. The side contacting the DNA samples were exposed to air and contained the negative replica of the DNA structures. We analyzed the DNA structures and their metallic replicas by tapping mode atomic force microscopy (AFM).We first demonstrated the principle …