Site-specific control of distances between gold nanoparticles using phosphorothioate anchors on DNA and a short bifunctional molecular fastener
Site-specific control of distances between gold nanoparticles using phosphorothioate anchors on DNA and a short bifunctional molecular fastener
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DOI：
10.1002/anie.200702569
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发表时间：
2007-01-01
影响因子：
16.6
通讯作者：
Lu, Yi
中科院分区：
文献类型：
--
作者：
Lee, Jung Heon;Wernette, Daryl P.;Lu, Yi
精确控制纳米材料之间的位置和距离是纳米科学技术的一个巨大挑战。迎接这一挑战是至关重要的，不仅要从根本上理解这些材料在纳米尺度上的量子效应，[1]而且要在纳米电子学，光子学和医学中的实际应用。已经报告了一些方法。[2]其中，“自下而上”组装，特别是使用DNA分子作为模板来定位纳米材料，是有希望的，[3]因为DNA已被证明是一种高度可编程的分子，导致2D [3c，e，4]和3D [5]纳米结构。尽管取得了进展，但用纳米材料功能化这些DNA纳米结构的方法是有限的。链烷硫醇修饰通常用于将DNA连接到金纳米颗粒（AuNPs）上，这在大多数情况下会在设计DNA纳米结构时引入切口或复杂化。[6，7]在此，我们报道了一种使用与短双功能紧固件偶联的硫代磷酸酯修饰的DNA（PS-DNA）沿沿着DNA链组装纳米颗粒的新方法，其中精确控制纳米颗粒之间的位置和距离（BF;方案1）。类似于分子锚，硫代磷酸酯允许在寡核苷酸合成期间修饰的可编程放置，其可以控制修饰的位置和数量。BF在一端具有可以结合AuNP的烷硫醇基团，在另一端具有可以结合修饰的DNA骨架上的硫代磷酸酯基团的碘乙酰胺基团。这种方法可以将纳米材料放置在DNA结构的任何选定的骨架位点，使得可以精确控制纳米颗粒沿着DNA的位置以及它们之间的距离，而不需要用大量DNA分子官能化AuNP [6]或纯化单官能化的纳米材料。[7]由于官能化是在DNA骨架上进行的，硫代磷酸酯几乎总是可用于结合，因此该方法可以容易地应用于2D和3D DNA纳米结构，而不需要在这些结构上引入切口，从而最小化影响结构稳定性的风险，以及增加将纳米材料固定在DNA纳米结构上任何期望位置的可能性。与使用DNA链连接AuNP和DNA结构不同，短得多的BF还以这样一种方式保持AuNP，即在DNA上存在较少的运动自由度，从而允许更精确地控制AuNP的位置和AuNP之间的距离。为了利用烷烃硫醇盐和硫代磷酸酯的不同反应性，我们选择N，N '-双（α-碘乙酰基）-2，2'-二硫代双（乙胺）（BIDBE）[8]作为双官能紧固剂的前体（BF，N-碘乙酰基-2-巯基乙胺;参见方案1，右）。BIDBE在两端含有碘乙酰胺基，在中间含有二硫键。碘乙酰胺官能团已被证明与硫代磷酸酯基团特异性反应，[9]而二硫键在还原为烷硫醇时可以选择性地结合AuNP。[10]为了证明BF与PS-DNA的特异性共价连接，如前所述合成BIDBE [8]，然后在50 ℃下用PS-DNA处理6小时，然后加入三-（2-羧乙基）膦盐酸盐（TCEP）将二硫键还原为硫醇盐。通过MALDI-TOF质谱法分析反应产物表明形成了BF-PS-DNA加合物（计算分子量（Mw）：8275 Da;实测Mw：8272+ 8 Da（0.05-0.1%）;参见支持性信息，图S1）。反应...
Precise control of the locations of and distances between nanomaterials is a great challenge in nanoscale science and technology. Meeting this challenge is critical, not only to a fundamental understanding of quantum effects of these materials at nanometer scales,[1] but also to practical applications in nanoelectronics, photonics, and medicine. A number of methods have been reported.[2] Among them,“bottom-up” assembly, particularly using DNA molecules as templates to position nanomaterials, is promising,[3] as DNA has been shown to be a highly programmable molecule resulting in 2D [3c, e, 4] and 3D [5] nanostructures. Despite the progress, methods to functionalize these DNA nanostructures with nanomaterials are limited. Alkane thiol modification on either end of DNA is usually used to attach DNA on gold nanoparticles (AuNPs), which in most cases introduces nicks or complications in designing DNA nanostructures.[6, 7] Herein we report a novel method to assemble nanoparticles along DNA strands with precise control of the position of and distance between nanoparticles using phosphorothioate-modified DNA (PS-DNA) coupled with a short bifunctional fastener (BF; Scheme 1). Similar to a molecular anchor, the phosphorothioate allows programmable placement of modifications during oligonucleotide synthesis that can control both the position and the number of modifications. The BF has an alkane thiol group at one end that can bind to a AuNP and an iodoacetamide group at the other end that can bind to a phosphorothioate group on a modified DNA backbone. This method can place nanomaterials at any selected backbone site of the DNA structure, making it possible to precisely control the position of the nanoparticles along DNA and the distances between them, without the need to functionalize AuNPs with a large number of DNA molecules [6] or purify monofunctionalized nanomaterials.[7] As the functionalization is made on the DNA backbone, at which the phosphorothioate is almost always available for binding, this method can be readily applied to 2D and 3D DNA nanostructures, without the need to introduce nicks on those structures, minimizing the risk of affecting the structural stability, as well as increasing the possibility of fastening nanomaterials at any desirable location on the DNA nanostructure. Instead of using DNA strands to connect AuNPs and DNA structures, the much shorter BF also holds the AuNPs in such a way that there is less freedom of movement on the DNA, allowing even more precise control of the positions of and distances between AuNPs. To take advantage of different reactivities of alkane thiolate and phosphorothioate, we chose N, N’-bis (α-iodoacetyl)-2, 2’-dithiobis (ethylamine)(BIDBE)[8] as a precursor to the bifunctional fastener (BF, N-iodoacetyl-2-mercaptoethylamine; see Scheme 1, right). BIDBE contains an iodoacetamide group at both ends and a disulfide bond in the middle. The iodoacetamide functional group has been shown to react with the phosphorothioate group specifically,[9] while the disulfide bond, upon reduction to an alkane thiol, can bind to AuNPs selectively.[10]To demonstrate specific covalent attachment of the BF to PS-DNA, BIDBE was synthesized as reported previously,[8] and then treated with PS-DNA at 508C for 6 h, followed by addition of tris-(2-carboxyethyl) phosphine hydrochloride (TCEP) to reduce the disulfide bond to a thiolate. Analysis of the reaction products by MALDI-TOF mass spectrometry indicated formation of BF-PS-DNA adducts (calculated molecular weight (Mw): 8275 Da; observed Mw: 8272+ 8 Da (0.05–0.1%); see Supporting Information, FigureS1). The reaction …