Vertically aligned diamond nanowires for DNA sensing.
Vertically aligned diamond nanowires for DNA sensing.
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DOI：
10.1002/anie.200801706
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发表时间：
2008-06
影响因子：
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通讯作者：
N. Yang;H. Uetsuka;E. Ōsawa;C. Nebel
中科院分区：
文献类型：
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作者：
N. Yang;H. Uetsuka;E. Ōsawa;C. Nebel
近年来，以Si、SiO_2、Au、玻碳、SnO_2和ZnO为原料，采用自底向上和自顶向下的方法制备纳米线引起了人们的广泛关注。[1]这些纳米线已被用于化学/生物化学传感应用，因为它们的重量轻，以及有时非凡的机械，电气，热，和多功能特性。[2]然而，这些纳米线在电解质溶液中不具有生化表面的期望的化学稳定性和再现性。需要显著改善对溶液中分析物的灵敏度、选择性、平行性、化学稳定性和生物相容性。金刚石是下一代传感器平台的一个有前途的选择[3]，因为它的化学稳定性，低背景电流和宽电位窗口。金刚石可以在恶劣的环境中生存，而其他材料如ZnO 2，SnO 2和Si则无法生存。随着掺杂水平的增加，金刚石从绝缘材料到半导体材料再到类金属导电材料。用氢和氧的表面终止也允许金刚石电极的电子性质的优化。金刚石对大的生物分子也具有生物相容性，例如DNA。[4]1997年，Shiomi首次实现了金刚石纳米线，[5]他展示了通过使用O2的反应离子蚀刻（RIE）形成多孔金刚石膜。后来，在2000年，通过多孔阳极氧化铝掩模蚀刻制备了纳米结构的金刚石蜂窝膜[6]; Shenderova等人总结了这些结果引发的工作。[7]2003年首次报道了通过在偏置电位下施加氢的微波等离子体来生长诱导形成纳米级管状结构。[8]2008年，Zou et al. [9]报道了使用自对准Au纳米点作为在利用氢/氩等离子体的偏压辅助反应离子蚀刻中的蚀刻掩模来制造纳米柱阵列。虽然这些成就表明，垂直排列的金刚石纳米线可以通过多种方法制备，但尚未报道其在电学或生物化学方面的应用。在此，我们首次介绍了垂直排列的金刚石纳米线在DNA传感方面的电化学应用。这种新的技术途径结合了金刚石的主要优点，如化学稳定性，生物相容性和硬度与DNA分子的几何控制键合，以实现DNA分子的行为“像在溶液中”的情况。这些类金属纳米线是由硼掺杂的单晶CVD金刚石（通过化学气相沉积产生）通过使用金刚石纳米颗粒作为硬掩模和通过使用RIE在O2/CF 4气体混合物中10秒来制造的。[10]这些线长3-10 nm，通常间隔11 nm（图1）。选择间隔约11 nm的纳米线是因为将DNA分子锚定到这些线上将导致约1012 cm 2的DNA密度，这对于高效的DNA传感是有希望的。纳米线的尖端用苯基电化学官能化[11]。[10]这种功能化的纳米线用于将几何控制的寡核苷酸分子键合到金刚石上。当DNA与苯基连接基团自对准时，纳米线尖端的功能化产生了由纳米线结构控制的分散的DNA键合模式。氧化还原指示剂如[Fe（CN）6] 3 H2O/4 H2O和嵌入剂如金属络合物已被广泛用于研究金和其他基底电极上的DNA传感。然而，还没有发表关于使用氧化还原指示剂的基于金刚石的生物传感器的工作。在此...
Nanowires from Si, SiO2, gold, glassy carbon, SnO2, and ZnO2 by bottom-up and top-down techniques have attracted much attention recently.[1] These nanowires have been used for chemical/biochemical sensing applications because of their low weight, as well as the sometimes extraordinary mechanical, electrical, thermal, and multifunctional properties.[2] However, these nanowires do not possess desired chemical stability and reproducibility of biochemical surfaces in electrolyte solutions. Significant improvements in the sensitivity, selectively, parallelism, chemical stability, and biocompatibility towards analytes in solutions are needed. Diamond is a promising choice for the next generation sensor platforms [3] because of its chemical stability, low background current, and wide potential window. Diamond survives in harsh environments in which other materials such as ZnO2, SnO2, and Si fail. Diamond varies from an insulating, to semiconducting, to metal-like conducting materials with increasing doping levels. Surface termination with hydrogen and oxygen also allows the optimization of electronic properties of diamond electrodes. Diamond is also biocompatible towards large biomolecules, such as DNA.[4] Diamond nanowires were first realized in 1997 by Shiomi,[5] who demonstrated the formation of porous diamond films by reactive ion etching (RIE) using O2. Later, in 2000, nanostructured diamond honeycomb films were prepared [6] by etching through a porous anodic alumina mask; the work triggered by these results are summarized by Shenderova et al.[7] Growth-induced formation of nanoscale tubular structures by applying a microwave plasma of hydrogen under a bias potential was first reported in 2003.[8] In 2008, Zou et al.[9] reported the fabrication of nanopillar arrays using self-aligned Au nanodots as an etching mask in bias-assisted reactive ion etching with a hydrogen/argon plasma. Although these achievements demonstrate that vertically aligned diamond nanowires can be fabricated by a variety of methods, no applications in electro-or biochemistry have been reported. Herein, we introduce for the first time the electrochemical application of vertically aligned diamond nanowires for DNA sensing. This new technological pathway marries major advantages of diamond such as chemical stability, biocompatibility, and hardness with geometrically controlled bonding of DNA molecules to realize behavior of the DNA molecules “like-in-solution” situation. These metal-like nanowires are fabricated from boron-doped single-crystalline CVD diamond (produced by chemical vapor deposition) by use of diamond nanoparticles as a hard mask and by use of RIE in O2/CF4 gas mixture for 10 s.[10] These wires are 3–10 nm long and typically spaced 11nm apart (Figure1). Nanowires separated by approximately 11nm were selected because anchoring DNA molecules onto these wires will result in a density of DNA of about 1012 cmÀ2, which is promising for DNA sensing with high efficiency. The tips of the nanowires were functionalized electrochemically [11] with phenyl groups.[10] Such functionalized nanowires are used to bond geometrically controlled oligonucleotide molecules to diamond. As DNA self-aligns with the phenyl linker groups, functionalization of the nanowire tips produces a pattern of dispersed DNA bonding governed by the nanowires structure.Redox indictors such as [Fe (CN) 6] 3À/4À and intercalators such as metal complexes have been widely used for the investigation of DNA sensing on gold and other substrate electrodes. However, no work has been published on diamond-based biosensors that use redox indicators. Herein …