Discovery of selective vapor response with nanostructures of butterfly wing scales

imgHello Earth! I would like to share with you our excitement about a recent breakthrough in GE’s Chemical and Biological Sensing Laboratory that was reported in a cover-story article in February issue of Nature Photonics.

Tropical Morpho butterflies are famous for their brilliant iridescent colors, which arise from ordered arrays of scales on their wings. In our paper, my team shows that the iridescent scales of the Morpho sulkowskyi butterfly give a different optical response to different individual vapors, and that this optical response dramatically outperforms that of existing nano-engineered photonic sensors. The reflectance spectra of the scales provide information about the nature and concentration of the vapors, allowing us to identify a range of closely related vapors-water, methanol, ethanol and isomers of dichloroethylene when they are analyzed individually. By comparing the reflectance as a function of time for different vapors, we deduce that wing regions with scale structures of differing spatial periodicity give contributions to the overall spectral response at different wavelengths. Our optical model explains the effect of different components of the wing scales on the vapor response, and could steer the design of new man-made optical gas sensors.

My research into butterfly wings was inspired by the review article written by Pete Vukusic and J. Roy Sambles in Nature in 2003 [see Nature 424,852 -855 (2003)]. In that article, the authors described the nanometer-scale photonic structures in the wing scales of the Morpho butterfly and the striking blue iridescence that they generate. Imagining a combination of this new to me knowledge with the optical sensing principles that I was practicing already, I realized that the underlying physics of this iridescence should be strongly influenced by the gas environment surrounding the nanostructures. After my initial careful experiments, it was clear that the underlying optical properties exhibited by the nanostructures on butterfly wings could offer a promising route to highly selective chemical sensing capabilities. I was fortunate to attract interest from several scientists to carry out together this small research further. The assembled research team that explored further the origin and details of this unique selective vapor response of butterfly wing scales. The team included Professor Helen Ghiradella from the Department of Biological Sciences, University at Albany; and Alexei Vertiatchikh, Katharine Dovidenko, Eric Olson, and James Cournoyer from GE Global Research.

Our next step is to find a way to mimic nature and to design acute and robust chemical sensors that will offer new attractive sensing solutions in the marketplace. That is what we are focused on solving. If successful, it could launch a new direction in the design of highly selective chemical sensors with straightforward colorimetric readout that could replace current complicated sensor arrays. We foresee that this kind of sensor could be in the market within the next five years. Of course this depends on the advances in fabrication technologies and further detailed testing.

Stay tuned for more news from GE Research!

Comments

Rad; This terrific! Also the article in the Gazette today(2 March 2007) was very nice. I like how you have taken the observations on natural systems and proposed that someone could/should be able to find a robust manufacturing process to make the snesors. GOOD LUCK.

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