Esmaspäeval, 23. septembril 2019 kell 14.15 toimub Physicumis, W.Ostwaldi 1, ruumis D312
Laserspektroskoopia ja Tahkiseteooria ühisseminar No 275
Esineb Prof. Dr. Stephane Petoud
Center for Molecular Biophysics CNRS, UPR 4301 45071 Orléans Cedex 2 France
Near-infrared Emitting Lanthanide Compounds: From Small Molecules to Nanoscale Systems
Fluorescence and luminescence are detection techniques that possess important advantages for bioanalytical applications and biologic imaging: high sensitivity, versatility and low costs of instrumentation. A common characteristic of biologic analytes is their presence in small quantities among complex matrices such as blood, cells, tissue and organs. These matrices emit significant background fluorescence (autofluorescence), limiting detection sensitivity.
The luminescence of lanthanide cations has several complementary advantages over the fluorescence of organic fluorophores and semiconductor nanocrystals, such as sharp emission bands for spectral discrimination from background emission, long luminescence lifetimes for temporal discrimination and strong resistance to photobleaching. In addition, several lanthanides emit near-infrared (NIR) photons that can cross deeply into tissues for non-invasive investigations and that result in improved detection sensitivity due to the absence of native NIR luminescence from tissues and cells (autofluorescence). The main requirement to generate lanthanide emission is to sensitize them with an appropriate chromophore (“antenna effect”).
Innovative approaches for the sensitization of NIR-emitting lanthanides will be described; the current limitation of low quantum yields experienced by most mononuclear lanthanide complexes is compensated for by using a large number of lanthanide cations and by maximizing the absorption of each discrete molecule, thereby increasing the number of emitted photons per unit of volume and the overall sensitivity of the measurement. To apply this concept, we have created several families of lanthanide compounds (nanocrystals, metal-organic frameworks and dendrimer complexes) and succeeded in generating highly emissive NIR reporters. We will discuss their designs, structures, photophysical properties and their applications for biological imaging in NIR microscopy.
PS For postgraduate students: Seminar belongs to the Programme of Doctoral seminars LOFY.00.004 and by visiting it you can earn credit points!