一輛堪稱世界最小的“電動(dòng)車”出現(xiàn)在最新一期英國(guó)《自然》雜志的封面上,，這是一個(gè)結(jié)構(gòu)特殊的分子，它也有四個(gè)“輪子”,，當(dāng)接收到電流時(shí)就向前“行駛”,，不過(guò)，它行駛的距離要以納米來(lái)計(jì)算,。
荷蘭格羅寧根大學(xué)等機(jī)構(gòu)的研究人員報(bào)告了這項(xiàng)成果,。他們合成的這個(gè)分子在中間有一根“主軸”，前后兩端各有兩個(gè)類似輪子的結(jié)構(gòu),。如果用特別小的探針碰一下這個(gè)分子,，為之提供電流，四個(gè)“輪子”就會(huì)開始旋轉(zhuǎn),，驅(qū)動(dòng)整個(gè)分子前行,。在銅板表面對(duì)這輛“電動(dòng)車”進(jìn)行的測(cè)試顯示，如果施加10次電流,，它可以前進(jìn)6納米（1納米為百萬(wàn)分之一毫米）,。
研究人員蒂博爾·庫(kù)貝納奇說(shuō)，這輛“電動(dòng)車”的原理與許多生物機(jī)體組織中天然存在的現(xiàn)象類似,，在機(jī)體組織中,，有些蛋白質(zhì)在受電流刺激后會(huì)變形，從而產(chǎn)生運(yùn)動(dòng),，肌肉的收縮就是基于這個(gè)原理,。本次研究顯示，可以在納米尺度上人工模擬這類現(xiàn)象,。
這種分子“電動(dòng)車”將來(lái)可用于許多微觀領(lǐng)域,，比如把微量藥物送達(dá)人體所需要的地點(diǎn)。不過(guò)研究人員表示，這還有很長(zhǎng)路要走,，因?yàn)楸敬螌?shí)驗(yàn)是在零下200多攝氏度的低溫和高度真空環(huán)境中完成的,，如何在常規(guī)環(huán)境下也能讓分子“電動(dòng)車”工作是首先要解決的問(wèn)題。(生物谷 Bioon.com)
doi:10.1038/nature10587
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Electrically driven directional motion of a four-wheeled molecule on a metal surface
Tibor Kudernac, Nopporn Ruangsupapichat, Manfred Parschau, Beatriz Maciá, Nathalie Katsonis, Syuzanna R. Harutyunyan, Karl-Heinz Ernst & Ben L. Feringa
Propelling single molecules in a controlled manner along an unmodified surface remains extremely challenging because it requires molecules that can use light, chemical or electrical energy to modulate their interaction with the surface in a way that generates motion. Nature’s motor proteins have mastered the art of converting conformational changes into directed motion, and have inspired the design of artificial systems3 such as DNA walkers and light- and redox-driven molecular motors. But although controlled movement of single molecules along a surface has been reported, the molecules in these examples act as passive elements that either diffuse along a preferential direction with equal probability for forward and backward movement or are dragged by an STM tip. Here we present a molecule with four functional units—our previously reported rotary motors—that undergo continuous and defined conformational changes upon sequential electronic and vibrational excitation. Scanning tunnelling microscopy confirms that activation of the conformational changes of the rotors through inelastic electron tunnelling propels the molecule unidirectionally across a Cu(111) surface. The system can be adapted to follow either linear or random surface trajectories or to remain stationary, by tuning the chirality of the individual motor units. Our design provides a starting point for the exploration of more sophisticated molecular mechanical systems with directionally controlled motion.
