生物谷綜合：日本科學(xué)家最新研究發(fā)現(xiàn),，通過(guò)觀察被陷入碳納米管中的單個(gè)分子的運(yùn)動(dòng),，就可以直接觀察到視覺(jué)形成的過(guò)程，此研究結(jié)果發(fā)表在7月出版的《自然—納米技術(shù)》（Nature Nanotechnology）期刊上。
眼睛中視網(wǎng)膜分子形狀的變化會(huì)刺激負(fù)責(zé)視覺(jué)的生物化學(xué)通道,，從而導(dǎo)致視覺(jué)的形成。通過(guò)將單個(gè)視網(wǎng)膜分子錨定在足球狀的C60富勒烯分子中,，Kazu Suenaga和同事就能夠?qū)⑺鼈儾东@在單壁的碳納米管中,，并用高分辨率的透射電子顯微鏡為其成像。用碳納米管做樣品支架可以確保單個(gè)分子之間有很好的隔離,，并能保護(hù)它們?cè)谟^察時(shí)免遭電子束的損傷,。
連續(xù)的透射電子顯微鏡圖像展現(xiàn)了視網(wǎng)膜分子在碳納米管中的移動(dòng)和形狀改變過(guò)程。盡管這種圖像展現(xiàn)的是視網(wǎng)膜分子在人工環(huán)境中的運(yùn)動(dòng),，與正常的生物學(xué)環(huán)境有差異,，但眼睛在觀察外界時(shí)會(huì)發(fā)生非常類似的過(guò)程，從而揭示出當(dāng)我們看見(jiàn)某種東西時(shí),，眼睛內(nèi)部究竟發(fā)生了什么事,。
本期的一篇新聞評(píng)述文章寫道：“這項(xiàng)工作首次觀察到了共軛碳鏈的動(dòng)力學(xué)行為，提供了一種在原子水平清晰度下研究視紫質(zhì)中視網(wǎng)膜分子作用的可能性,。”
原始出處:
Nature Nanotechnology 2, 422 - 425 (2007)
Published online: 1 July 2007 | doi:10.1038/nnano.2007.187
Subject Categories: Carbon nanotubes and fullerenes | Surface patterning and imaging
Imaging the dynamic behaviour of individual retinal chromophores confined inside carbon nanotubes
Zheng Liu1, Kazuhiro Yanagi2, Kazu Suenaga1, Hiromichi Kataura2 & Sumio Iijima1
Abstract
Retinal is the molecule found in photoreceptor cells that undergoes a change in shape when it absorbs light. Specifically, the cis/trans isomerization of a carbon–carbon double bond in this chromophore sets in motion the chain of biochemical processes responsible for vision1, 2, 3. Here, we obtain atomically resolved images of individual structural isomers of the retinal chromophore attached to C60 molecules and study their dynamic behaviour inside a confined space—that is, inside single-walled carbon nanotubes—using high-resolution transmission electron microscopy (HR-TEM). Sequential HR-TEM images with sub-second time resolution directly reveal the isomerization between the cis and all-trans forms of retinal, as well as conformational changes and volume-conserving effects. This work opens up the possibility of investigating in vitro the biological activities of these photoresponsive molecules on an individual basis, and the molecular imaging technique described here is a general one that can be applied to a wide range of systems.
Research Center for Advanced Carbon Materials, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8565, Japan
Nanotechnology Research Institute (NRI), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8562, Japan
Correspondence to: Kazu Suenaga1 e-mail: [email protected]
