A Photon-Fueled DNA Nanodevice that Contains Two Different Photoswitches
A Photon-Fueled DNA Nanodevice that Contains Two Different Photoswitches
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DOI：
10.1002/anie.201106093
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发表时间：
2012-01-01
影响因子：
16.6
通讯作者：
Asanuma, Hiroyuki
中科院分区：
文献类型：
--
作者：
Nishioka, Hidenori;Liang, Xingguo;Asanuma, Hiroyuki
DNA是一种很有前途的自组装纳米材料，可用于构建精细的纳米结构和纳米器件。[1-5]然而，当使用短DNA寡核苷酸作为燃料来驱动纳米器件时，废物逐渐积累并降低了操作效率。[3，4]因此，已经努力构建使用“清洁”燃料的新纳米器件。例如，刘和同事利用电信号可逆地驱动DNA开关。[6]我们建造了光子燃料的纳米机器，在许多工作周期后不会恶化。[7]基于偶氮苯修饰的DNA中DNA杂交的可逆光调控，构建了一种光子驱动的DNA纳米器件。平面反式偶氮苯插入相邻碱基对之间，并通过堆叠相互作用稳定双链体，而非平面顺式偶氮苯通过空间位阻使双链体不稳定。[8，9]迄今为止，光开关基本上包含单一物质，例如偶氮苯-4’-羧酸（Azo）或2，6-二甲基偶氮苯-4’-羧酸（DMAzo;方案1）。紫外线（310- 370 nm）或可见光（大于400 nm）诱导此类化合物的反式和顺式形式之间的可逆异构化。我们试图开发一种光开关，该光开关在其他波长的照射下发生光异构化，以使光开关多样化，并使其适用于应避免UV光的各种目的。在这项研究中，我们合成了一种偶氮苯衍生物，在可见光照射下可逆地光异构化。当束缚在d-苏氨醇上并与DNA连接时，2，6-二甲基-4-（甲硫基）偶氮苯-4 ′-羧酸（S-DMazo，方案1）具有足够高的顺式含量、可接受的热稳定性和高的光调节效率。通过将Azo和S-DMAzo结合，产生了一种光子燃料的DNA纳米机器，该机器在不同波长的光照射下以跷跷板状运动移动。偶氮苯及其烷基衍生物的反式异构体在约320 nm（π-π* 跃迁）处具有最大吸收（lmax），并且富含顺式的形式可以通过波长在310-370 nm之间的光照射获得。[10]通过在帕拉引入给电子基团，可以得到向可见光区红移较大的偶氮苯衍生物。然而，π-π* 和n-π* 跃迁的重叠（在约。450 nm）使得难以获得富含顺式的形式，并且由这些取代基引起的更强的共轭以及电子效应降低了顺式形式的热稳定性。[11]为了避免反式形式的π-π* 和n-π* 跃迁的大重叠，并确保顺式形式的高热稳定性，理想的偶氮苯衍生物将在约400 nm处具有α 1最大值。我们设计了S-DMAzo来满足这些要求。在S-DMAzo中，在远端苯环的帕拉处的甲硫基导致反式的Imax值向400 nm的红移。[12]远端环邻位的两个甲基增强了光调节效率，
DNA is a promising, self-assembling nanomaterial for the construction of delicate nanostructures and nanodevices.[1–5] However, when short DNA oligonucleotides are used as the fuel to drive a nanodevice, the waste gradually accumulates and lowers the operating efficiency.[3, 4] Accordingly, efforts have been made to construct new nanodevices that use “clean” fuels. For example, Liu and co-workers utilized electric signals to reversibly drive a DNA switch.[6] We constructed photon-fueled nanomachines that did not deteriorate after many working cycles.[7] A photon-fueled DNA nanodevice has been constructed based on the reversible photoregulation of DNA hybridization in azobenzene-modified DNA. The planar transazobenzene intercalates between adjacent base pairs and stabilizes the duplex through stacking interactions, whereas the nonplanar cis-azobenzene destabilizes the duplex by steric hindrance.[8, 9] To date, photoswitches have essentially contained a single species, such as azobenzene-4’-carboxylic acid (Azo) or 2, 6-dimethylazobenzene-4’-carboxylic acid (DMazo; Scheme1). Ultraviolet (310–370nm) or visible light (l greater than 400 nm) induces reversible isomerization between the trans and cis forms of such compounds. We sought to develop a photoswitch that photoisomerizes upon irradiation at other wavelengths to diversify the photoswitches and to make them applicable for various purposes where UV light should be avoided. In this study, we synthesized an azobenzene derivative that photoisomerizes reversibly upon irradiation with visible light. When tethered onto d-threoninol and linked to DNA, 2, 6-dimethyl-4-(methylthio) azobenzene-4’-carboxylic acid (S-DMazo, Scheme 1) had a sufficiently high cis content, acceptable thermal stability, and a high photoregulatory efficiency. By combining Azo and S-DMazo, a photon-fueled DNA nanomachine that moved with a seesaw-like motion upon irradiation with light of different wavelengths was produced. The trans isomers of azobenzene and its alkyl derivatives have absorption maxima (lmax) at around 320nm (π–π* transition), and the cis-rich form can be obtained by irradiation with light of wavelengths between 310–370 nm.[10] An azobenzene derivative with a large bathochromic shift to the visible region can be obtained by the introduction of an electron-donating group at the para position. However, the overlap of π–π* and n–π* transitions (at ca. 450 nm) makes it difficult to obtain the cis-rich form, and the stronger conjugation as well as the electronic effects caused by these substituents decrease the thermal stability of the cis form.[11] To avoid large overlap of the π–π* and n–π* transitions in the trans form and to ensure a high thermal stability in the cis form, the ideal azobenzene derivative would have al max at around 400 nm. We designed S-DMazo to satisfy these requirements. In S-DMazo, the methylthio group at the para position of the distal benzene ring causes a bathochromic shift in the lmax value of the trans form to 400 nm.[12] The two methyl groups at the ortho positions of the distal ring enhance the photoregulatory efficiency and the