Mapping microscopic viscosity using molecular rotors
DIPC Seminars
- Speaker
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Marina K. Kuimova (Imperial College London, UK)
- When
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2014/07/11
14:00 - Place
- Donostia International Physics Center (DIPC).Paseo Manuel de Lardizabal, 4 , Donostia
- Add to calendar
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Mapping microscopic viscosity using molecular rotors
Marina K. Kuimova
Department of Chemistry, Imperial College London,
Exhibition Road, London, SW7 2AZ, UK
e-mail: m.kuimova@imperial.ac.uk
Viscosity is one of the main factors which influence diffusion in condensed
media. In a cell viscosity can play a role in several diffusion mediated
processes, such as drug delivery, signalling and mass transport. Previously,
alterations in viscosity in cells and organs have been linked to malfunction;
however, mapping viscosity on a single-cell scale remains a challenge.
We have imaged viscosity inside lipid mono- and bi-layers, in cells and in
atmospheric aerosol particles using fluorescent probes, called molecular
rotors [1]. In molecular rotors the speed of rotation about a sterically
hindered bond is viscosity-dependent [1]. This approach enabled us to
demonstrate that viscosity distribution in a cell is highly heterogeneous and
that the local microviscosity in hydrophobic cell domains can be up to 100
times higher than that of water [2-5]. These conclusions have been confirmed
by monitoring the decay and reaction rates of short-lived excited state of
molecular oxygen, singlet oxygen, on a single cell level [3]. We also
determine particle viscosity of complex, atmospherically relevant organic
aerosols and monitor its temporal changes in real time, over time scales
relevant for the atmosphere.
References
[1] M. K. Kuimova, Phys Chem Chem Phys, 2012, 14, 12671
[2] M. K. Kuimova, G. Yahioglu, J. A. Levitt, K. Suhling, J. Amer. Chem.
Soc., 2008, 130, 6672
[3] M. K. Kuimova, S. W. Botchway, A. W. Parker, M. Balaz, H. A. Collins,
H. L. Anderson, K. Suhling, P. R. Ogilby, Nature Chem., 2009, 1, 69-73
[4] N. A. Hosny, G. Mohamedi, P. Rademeyer, J. Owen, Y. Wu, M-X. Tang, R.
J. Eckersley, E. Stride and M. K. Kuimova, Proc. Nat. Acad. Sci. USA, 2013,
110, 9225–9230
[5] I. Lopez-Duarte, T. T. Vu, M. A. Izquierdo, J. A. Bull, M. K. Kuimova.
Chem. Commun., 2014, DOI: 10.1039/C3CC47530A