Moved by light - as if by magic

(Nanowerk News) A few months ago Münster scientists showed that certain molecules – so-called nano-containers – can be guided by light alone. This study has now been singled out for special praise – according to the journal Optics and Photonics News (pdf) it is among the 30 best pieces of work done in 2010. In a special issue published at the end of the year the journal – an international opinion-former – traditionally looks back on the research highlights of the past year in the fields of optics and photonics. The Münster study, which involved scientists working with Prof. Cornelia Denz (physics) and Prof. Luisa De Cola (chemistry), even made it on to the front page of the special issue, which was a particular honour.
nano-containers guided by light
Münster scientists have shown that so-called nano-containers – shown here – can be guided by light alone.
"We're delighted that the hierarchical arrangement of molecules by means of light has received such a good reception by the research community," says physicist Mike Wördemann, who played a key role in the study. "This interdisciplinary work was only possible as a result of the first-class collaboration between physicists and chemists." The study was carried out jointly with Münster University's Centre for Nonlinear Science as part of the first German-Chinese Transregio Collaborative Research Centre (TRR 61) of the German Research Foundation.

The team of scientists has developed a new type of method to arrange miniscule nano-containers which are able to transport a wide variety of "guest molecules" such as medicines or other active ingredients in cavities inside themselves. It is not even necessary to touch the nano-containers – they are guided solely – as if by magic – by means of light from a non-visible, infrared high-performance laser. In this way completely new possibilities are created for the extremely precise control of artificial, nano-structured materials. For medical applications, for example, filling a container (whether a medicine or an active ingredient) could be precisely positioned and the effect likewise precisely controlled.

The basic idea had already been published by the researchers in August in the interdisciplinary journal Advanced Materials ("Dynamic and Reversible Organization of Zeolite L Crystals Induced by Holographic Optical Tweezers"). Inspired by the universal principles of self-organization in nature, the scientists arranged the containers – which themselves contained highly ordered "guest molecules" – in an ordered structure and thus created a so-called hierarchical, supermolecular arrangement. This method, developed by close collaboration between physicists and chemists, has made it possible for the first time to steer each individual nano-container directly and arrange them on the nanometer scale with the greatest possible precision.
One special quality the containers have is their internal structure with innumerable, strictly arranged cavities which can be filled with a wide variety of "guest molecules". This high degree of order on the nanometer scale can, in itself, lead to fascinating new properties in the materials produced which cannot be realized with the "guest molecules" alone, say the scientists.
Source: Westfälische Wilhelms-Universität Münster