n°28I quarterlyI January 2013 Live from the Labs | 11 w Chemistry Researchershavedevisedanewmethodfordesigning morereliableelectronictonguesthatcaneven“visualize”tastes. Grenoble Electronic Tongues that Can See Taste BY eddydelcher q a novel electronic Edissolved substances. They have many applications, plasmon resonance ©TINuROu-BO.ytongue can translatetastes into specificlandscapes with thehelp of surfacefrom assessing foods’ freshness to detecting harmfullectronic tongues are devices capable of recognizing substances in wastewaters. The receptors of conventional elec- imaging (sPri). tronic tongues consist of complex molecules known to bind with particular chemical compounds. The large number of complex molecules required to create an array of receptors usually makes developing electronic tongues time-consuming and arduous. A team of researchers bridging several laboratories1 has formed an array of receptors. Bindings for each analyte. In other words, our managed to speed up the process by using lactose and sulfated between receptors and chemical com- system allows us to see tastes,” explains lactose—two small and easily accessible molecules—as building pounds were measured via Surface Yanxia Hou-Broutin, from the SPrAM blocks to design receptors.2 Taking inspi- Plasmon Resonance imaging (SPRi), an laboratory,1 who has been leading the ration from the heparan sulfates’ ability HEpArAN suLFATEs. optical detection technique never used project for the past four years. “Unlike to bind with proteins, the team mixed Polysaccharides before in this field. Each time a compound previous systems, our method allows all negatively-charged sulfated lactose and binding properties. binds with a receptor, electron oscillations receptors to be linked,” she adds. “Thiswith varying neutral lactose molecules to create drop- (plasmons) change. This in turn alters the enables us to identify defective receptors lets of varying concentration ratios, each way light isreflected on the prism’s surface, and eliminate any abnormal signal. It can displaying different binding properties. eachalteration being measured optically. be compared to our brain’s ability to re- The droplets were then deposited on a “Using this real-time monitoring construct an image from a screen, even gold-layered optical prism, where they technique, a 3D landscape can be drawn when defective pixels are present.” The new tongues are also cheaper to develop, and can be re-used and/or kept for months. “We are now exploring the ENS u analysis of complex mixtures such as beer, wine, and milk. While still under . RAGAETd development, our system can already differentiate between the three, and de- B J. : PHOTOS termine whether a milk sample is spoiled just by looking at its 3D landscape,” © concludes the researcher. 01.LaboratoireStructuresetpropriétésd’architectures moléculaires(CNRS/CEA/universitéJoseph- FourierGrenoble) ;Institutdechimiemoléculaireet ancestor diverged in diet: plants 01. laboratoire de géologie delyon (cnrs /ens lyon / q first superior desmatériauxd’Orsay(CNRS/universitéParis-Sud) ; only forParanthropus, as confirmed by universitélyon-1). right molar Institutdebiologiestructurale(CNRS/CEA/ their facial and dental anatomy, while (cnrs /universitétoulouse-III /université de of an early 02.yanxiaHouJoseph-FourierGrenoble). profilesforevolution“Continuousal.,etniversitéunthropologie moléculaire et imagerie de synthèse a02. strasbourg). Homo (left), third electronictongue-basedanalysis,”Angewandte Homo were carnivorous, hunting with 03.V. Balter et al., “evidence for dietary change but not superior right Chemie,2012.dOI:10.1002/anie.201205346. stone tools.as Balter explains, “the lack landscape use insouthafrican early hominins,” molar of a, 2012. 489: 558-60.Nature of competition for food allowed the two Paranthropus groups to cohabit for almost a million lgl,lyon. and first inferior (middle),robustuson:InformatIontactc years.”the team suggests that meat Vincent Balter right molar contactInformatIon:vincent.balter@ens-lyon.fr> consumption led toHomo’s increased of an early sPram,grenoble. brain size and ultimate survival. Homo (right). > yanxia.hou-broutin@cea.frnYanxia Hou-Brouti
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