n°28I quarterlY I JanuarY 2013 Innovation | 17 diabetes Novel Bioelectronic Sensor BYJean-PhIlIPPeBralY “They actually adjust their electrical activity accord- /MCu ing not only to the level of glucose, but also of various ORNAT w very day, and several times a day, millions of nutrients and hormones.” This electrical activity, © Y. B people have to prick their fingers to check their which is directly correlated with the insulin needs of blood glucose level,and self-inject a dose of insulin the body, is measured using microelectrodes on the q the array of 60 because they suffer from type 1 diabetes. This illness chip. The bioelectric sensor is able to calculate in real microelectrodes on is caused by the destruction of pancreatic ß cells time the quantity of insulin required and when it langerhans (darkwhich the islets of which normally secrete insulin and control blood should be delivered. spots) are cultured glucose levels. The researchers have recently succeeded in cul- for weeks. Implantable glucose sensors connected to insu- turing ß cells on an electronic chip capable of mea- lin pumps have been on the market for several years, suring these electrical variations in real time over Pessac but they have limitations, particularly in terms of several weeks, something that had never been done sensitivity and reaction times. Therefore, research- before. The team has filed an international patent to Talence ers from the Bordeaux-based laboratories CBMN1 protect its invention. “First of all, we hope to be able and IMS2 are working on a new bioelectronic sensor to use this technology to test the effect of candidate contactInformatIon: that could overcome these drawbacks by fixing drugs on ß cells,” explains Sylvie Renaud, of IMS. cBmn, Pessac. ß cells onto an electronic chip. “Fashioned by evolu- A first prototype is scheduled for2014. > j.lang@iecb.u-bordeaux.frJochen Lang tion, these cells constitute the most sophisticated 01.Chimie et biologie des membranes et nano-objets (CNRS / IPB / Ims,talence. tool for determining insulin requirements,” explain université Bordeaux-I). > sylvie.renaud@ims-bordeaux.frenaudrSylvieniversitéuLaboratoire Intégration du matériau au système (CNRS /02. CBMN researchers Jochen Lang and Bogdan Catargi. Bordeaux-I / Institut Polytechnique de Bordeaux). PicoSeq New Sequencing Method Pinned Down BY grégorY fléchet bias,” explains vincent Croquette, bio- cule closes, but pauses each time it en- physicist at the LPS.1 The strategy devel- counters one of these small fragments,” w esearchers have designed a new oped by the scientist and his team in- explains the researcher. The analysis ofr dNa sequencing methodthat could be volves carrying out sequencing from the temporary blockages generated by both cheaper and more precise than singledNA molecules. This recently pub- each of these oligonucleotide fragments Paris those in use. It is being developed com- lished innovative approach2 is based on provides a faithful imprint of the mercially by the start-up PicoSeq, the “mechanical” opening of the double sequence of the initial dNA molecule, launched in June 2012. The technology strand ofdNA to be decoded. To do this, it based on the laws ofdNA complementar- overcomes some of the main drawbacks is necessary to give thedNA a hairpin ity. This method also has a key advantage linked with existing techniques. “Current structure, using a complementarydNA over available sequencing techniques: methods involve multiplying in large fragment and a ligase enzyme. Placed in unlike these, it enables scientists to map numbers thedNA sequence to be ana- solution, this “dNA hairpin” is then at- certain types of repeated sequences in- lyzed. Yet this procedure often induces tached to a magnetic bead by one of the volved in serious genetic pathologies two branches of the hairpin, while the such as Huntington’s disease. This advan- magnet opeNINg ofTHe other is securely fastened to a glass plate. tage could allow PicoSeq to find a niche in dNaMoLeCuLe using magnets to pull on the beads, the the highly competitive market of genetic forCe double-stranded molecule can then be sequencing. opened up like a zip. Small fragments of 01.Laboratoire de physique statistique de l’eNS (eNS / magnetIc synthetic nucleic acids—oligonucle- CNRS /université Pierre et Marie Curie /université Bead Parisdiderot). glass otides of random sequence such as CTg, 02. v. Croquette et al., “Single-molecule mechanical Plate Agg,gAg—are added to the solution and 2012. 9: 367-72. Nature Methods,identification and sequencing,” thus hybridize through complementarity q Principle of the SequeNCST with the single-strandeddNA: a CTg se-e ofereINT “unzipping”dna © TCC, and so on. “When the force exerted > vincent.croquette@lps.ens.frVincent CroquetteCNRS, Paris.sPl withggAC, Agquence always pairs witha”NINrpI a “daSHaeqon:InformatIontactcuredCTruSTsnovel Pico technology, based on strands for decoding. on thedNA hairpin is released, the mole-
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