Watching Single Macromolecules Move in Response to Light
Nature has long inspired scientists with its seemingly unlimited ability to harness solar energy and to utilize it to drive various physiological processes. With the help of man-made molecular photoswitches, we now have the potential to outperform natural systems in many ways, with the ultimate goal of fabricating multifunctional materials that operate at different light wavelengths.
An important challenge in developing light-controlled artificial molecular machines lies in attaining a detailed understanding of the photoisomerization-coupled conformational changes that occur in macromolecules and molecular assemblies. A team of chemists and physicists at Humboldt-Universität zu Berlin, led by David Bléger and Jürgen P. Rabe, member of IRIS Adlershof, have now used force microscopy to provide interesting insights into the behavior of individual photoresponsive molecules and to identify contraction, extension, and crawling events accompanying light-induced isomerization. In particular they have realized a system, in which single macromolecules can “work”, i.e. they were reversibly contracted and stretched on a modified graphite surface by using UV- and blue light, respectively.
The paper by C.-L. Lee, T. Liebig, S. Hecht, D. Bléger, and J.P. Rabe was published in the current issue of ACS Nano (DOI: 10.1021/nn505325w), and has been highlighted with a “Perspective” by ACS & ACS Nano (DOI: 10.1021/nn506656r).