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MA: Fachverband Magnetismus

MA 2: Focus Session "Nanoparticles, Nanocrystals and Colloids" (jointly with BP, CPP, HL), Organization: Oleg Petracic (Ruhr-Universität Bochum)

MA 2.5: Topical Talk

Monday, March 14, 2011, 12:30–13:00, HSZ 103

Ion and pH sensing with colloidal nanoparticles: tailoring hybrid FRET-based nanobiosensors — •Martin Oheim — Centre National de la Recherche Scientifique, CNRS UMR8154; Institut National de la Santé et de la Recherche Médicale - INSERM U603; Université Paris Descartes, Laboratory of Neurophysiology & New Microscopies

In biological cells, the free cytoplasmic ion concentration ([Ca2+]i)plays important roles in a plethora of intracellular signalling cascades. One way to attain specificity and to increase the bandwidth of Ca2+ signaling is the confinement of excursions of [Ca2+]i from baseline to micro- and nanoscale domains. Due to their ephemerous nature (nm scale, ms kinetics) the experimental detection of Ca2+ microdomains has presented a major challenge to microscopists. In my contribution I will present ongoing efforts of a franco-german-american 'nanoFRET' consortium that aims at conceptualizing, designing, validating and using novel hybrid nano-particle/organic dye-based nanobiosensors for the detection of intracellular ion-concentration nanodomains. After a swift motivation of our "pointilistic" imaging approach and the presentation of the general sensor concept, I will discuss how core/shell properties, donor-acceptor distance, stoichiometry and surface effects affect sensor performance. Preliminary sensing applications of Ca2+ and protons will be presented. I shall equally discuss the challenges for loading and imaging single-nanoparticle in live cells and ways to address these.