Magnetically Driven Single DNA Nanomotor
Magnetically Driven Single DNA Nanomotor
复制标题
DOI：
10.1002/smll.201001559
复制
发表时间：
2011-03-07
期刊：
影响因子：
13.3
通讯作者：
Tan, Weihong
中科院分区：
文献类型：
--
作者：
Bamrungsap, Suwussa;Phillips, Joseph A.;Tan, Weihong
设计了一种由振荡磁场梯度驱动的 DNA 纳米马达。纳米马达由 DNA 发夹组成，固定在微通道内的玻璃表面上，随后与磁性颗粒结合。然后使用外部磁场梯度对垂直于玻璃表面的磁性颗粒施加力，从而打开 DNA 发夹。 DNA发夹在打开过程中5'端和3'端的分离被解释为该纳米电机的动力冲程，而发夹的杂交则被解释为恢复冲程。发夹分子的运动可以通过荧光团和茎端猝灭剂之间的荧光共振能量转移（FRET）来监测。[9-11]与其他DNA纳米电机系统（其中循环涉及添加几条DNA链）相比，磁性发夹DNA纳米电机可以通过简单应用外部磁场梯度来操作。因此，这种磁力驱动的发夹 DNA 纳米电机在每次循环后不添加 DNA 燃料，也不产生 DNA 废物，此外它还可以在室温下低盐浓度下运行。表 1 总结了 DNA 发夹和生物素化接头。具体来说，选择 DNA 发夹结构是因为它们可以从“闭合”（收缩）状态切换到“打开”（延伸）状态 状态。每个 DNA 发夹在环中有 20 个胸苷 (T) 碱基，在茎部分有 6、9 或 12 个碱基对（6ds、9ds 或 12ds）。为了可视化两种状态之间的运动，将荧光团（Fluorescien，FAM）附着在茎的一个臂上，并将猝灭剂（Dabcyl，DAB）附着在茎的另一臂上。 Poly T（20 个碱基）用作 DNA 发夹和 3' 端磁珠之间的间隔物，5' 端掺入 15 个碱基，与固定在玻璃表面的 DNA 连接体杂交。需要指出的是，FRET 对对于运动功能来说不是必需的，但它提供了一种监控电机运动的便捷方法。荧光强度与茎端FRET对之间的距离有关，该距离指示DNA纳米马达运动的状态（闭合或打开）。[9-11]如图1所示，外部磁场吸引与DNA分子探针5'端缀合的磁珠，从而触发DNA发夹的打开和关闭。为了控制运动，3’端被拴在玻璃表面上。在没有磁场的情况下，DNA 发夹处于收缩状态，荧光团被 FRET 猝灭。当施加外部磁场时，磁珠被吸引到
A DNA nanomotor has been designed that is fueled by an oscillating magnetic field gradient. The nanomotor consists of DNA hairpins that are immobilized on a glass surface inside a microchannel and subsequently conjugated to magnetic particles. An external magnetic field gradient is then used to apply a force on the magnetic particles perpendicular to the glass surface, thereby opening the DNA hairpins. The separation of the 5’and 3’ends of the DNA hairpin during opening is interpreted as the power stroke of this nanomotor and the hybridization of the hairpin as the recovery stroke. The movement of the hairpin molecule can be monitored by fluorescence resonance energy transfer (FRET) between a fluorophore and a quencher on the stem ends.[9–11] Compared with other DNA nanomotor systems, in which the cycles involve the addition of several DNA strands, the magnetic hairpin DNA nanomotor can be operated by the simple application of an external magnetic field gradient. As such, this magnetically driven hairpin DNA nanomotor adds no DNA fuels and generates no DNA waste products after each cycle, in addition to which it can be operated at room temperature with a low salt concentration.The DNA hairpins and biotinylated linker are summarized in Table 1. Specifically, DNA hairpin structures were selected because they can be switched from the “closed”(contracted) state to the “open”(extended) state. Each DNA hairpin has 20 thymidine (T) bases in the loop and 6, 9, or 12 base pairs (6ds, 9ds, or 12ds) in the stem part. In order to visualize movement between the two states, a fluorophore (Fluorescien, FAM) is attached to one arm of the stem and a quencher (Dabcyl, DAB) on the other arm of the stem. Poly T (20 bases) was used as the spacer between the DNA hairpins and the magnetic beads at the 3’end, and 15 bases were incorporated at the 5’end to hybridize with a DNA linker that was immobilized on a glass surface. It is necessary to point out that the FRET pair is not needed for motor function but gives a convenient way to monitor the motion of the motor. The fluorescence intensity is related to the distance between the FRET pair in the stem ends, which indicates the state (closed or open) of the DNA nanomotor movement.[9–11] As shown in Figure 1, an external magnetic field attracts the magnetic beads, which are conjugated to the 5’end of the DNA molecular probes, to trigger the opening and closing of DNA hairpins. In order to control the movement, the 3’end is tethered to a glass surface. In the absence of the magnetic field, the DNA hairpins are in the contracted state and the fluorophore is quenched by FRET. When the external magnetic field is applied, the magnetic beads are attracted to