A freight train of nanotubes for cargo transport on the nanoscale.
A freight train of nanotubes for cargo transport on the nanoscale.
复制标题
DOI：
10.1002/anie.200803021
复制
发表时间：
2008-10
影响因子：
--
通讯作者：
M. Burghard
中科院分区：
文献类型：
--
作者：
M. Burghard
在微米或纳米尺度上的纳米颗粒或分子的靶向运输是一个活跃的跨学科研究领域[1]，其承诺许多应用，例如纳米探针或药物活性化合物到细胞中的定义插入[2]以及生物传感[3]和微流体中的应用。[4]原则上，传输可以由光驱动，也可以由热能或化学能驱动。初始策略包括将纳米物体耦合到可以在液体介质内自主移动的催化纳米粒子。例如，当将由金和铂段组成的纳米棒引入H2 O2水溶液中时，过氧化物在铂表面上发生局部分解，形成氧气（图1a）。[5]模型计算表明，金属/液体界面张力沿着杆的变化与所得的氧浓度梯度是负责推进速度为每秒几微米。[5，6]然而，确切的机制仍然是目前调查的主题。讨论中的替代机制包括棒表面的离子流[7]和氧气泡的释放。[8]在最近的研究中，聚合物微粒通过静电或蛋白质-配体相互作用结合到Pt/Au纳米棒的一端。[9]虽然货物的附着使马达的速度变慢，但它们可以在H2 O2溶液中运输直径高达约1 μm的颗粒。运输发生在一个有针对性的方式在过氧化氢梯度内的浓度最大值，一种类型的“趋化性”，已被记录以前的空载电机。[10]此外，将短的镍段插入到马达中能够使马达/颗粒混合物在磁场中定向运动。SiO2微粒的表面涂覆有用于分解H2 O2的分子催化剂，可作为替代催化纳米马达。到目前为止，这种颗粒已经提供了荧光标记，以实现更好的定位;[11]然而，它们应该同样适合于运输较大的货物。进一步高度
The targeted transport of nanoparticles or molecules on the micrometer or nanometer scale is an active interdisciplinary area of research [1] that promises numerous applications, such as the defined insertion of nanoprobes or pharmaceutically active compounds into cells [2] and applications in biosensing [3] and microfluidics.[4] The transport can in principle be driven by light, as well as by thermal or chemical energy. An initial strategy comprises the coupling of the nanoobject to a catalytic nanomotor that can move autonomously within a liquid medium. For example, when bimetallic nanorods consisting of a gold and a platinum segment are introduced into an aqueous solution of H2O2, local decomposition of the peroxide takes place on the platinum surface with the formation of oxygen (Figure 1a).[5] Model calculations suggest that the variation in the metal/liquid interfacial tension along the rod associated with the resulting oxygen concentration gradient is responsible for the propulsion with speeds of a few micrometers per second.[5, 6] However, the precise mechanism is still the subject of current investigations. Among the alternative mechanisms under discussion are ion currents at the rod surface [7] and the release of oxygen bubbles.[8] In a recent study, polymer microparticles were bound to one end of Pt/Au nanorods by electrostatic or protein–ligand interactions.[9] Although the attachment of the cargo makes the bimetallic motors slower, they can transport particles with a considerable diameter of up to about 1 μm in a solution of H2O2. The transport takes place in a targeted manner within a hydrogen peroxide gradient towards the concentration maximum, a type of “chemotaxis” that had been documented previously for unloaded motors.[10] Moreover, the interposition of short nickel segments into the motor enabled the directed movement of the motor/particle hybrids in a magnetic field.SiO2 microparticles whose surface is coated with a molecular catalyst for the decomposition of H2O2 serve as alternative catalytic nanomotors. Until now, such particles have been provided with a fluorescent marker to enable better localization;[11] however, they should be equally suitable for the transport of larger cargos. A further highly