Speaker
Prof.
Ralf Metzler
(University of Potsdam)
Description
A surging amount of experimental and simulations studies reveals persistent
anomalous diffusion in the membranes and volume of living biological cells
as well as other complex fluids [1]. This anomalous diffusion is observed
for micron-sized objects down to labelled single molecules such as green
fluorescent proteins [2].
In this talk I will present results from large scale computer simulations
and stochastic analysis of the motion of lipids and embedded proteins in
lipid bilayer model membranes [3], indicating that increased disorder leads
to longer and longer lasting anomalous diffusion. In particular, the motion
of lipids and proteins can become non-Gaussian [3]. In the membranes of living
cells anomalous diffusion of embedded protein channels can last over several
hundreds of seconds [4].
Anomalous diffusion inside the volume of cells will be discussed, as well. In
particular, the emergence of non-Gaussian diffusion patterns for both Fickian
and non-Fickian diffusion will be addressed within the framework of diffusing
diffusivities [5].
The observed stochastic dynamics may be ergodic or not, depending on the
exact physical mechanisms governing the motion of the test particle. The
talk will discuss how non-ergodic behaviour needs to be taken into account
when interpreting data from stochastic systems. In addition effects of ageing
will be explained [6].
[1] F. Hofling and T. Franosch, Rep Progr Phys 76, 046602 (2013);
K. Noerregaard, R. Metzler, C. M. Ritter, K. Berg-Soerensen, and L. B.
Oddershede, Chem. Rev. 117, 4342 (2017).
[2] C Di Rienzo, V Piazza, E Gratton, F Beltram, and F Cardarelli, Nature Comm
5, 5891 (2014).
[3] J-H Jeon, HM-S Monne, M Javanainen, and R Metzler, Phys Rev Lett 109,
188103 (2012); J-H Jeon, M Javanainen, H Martinez-Seara, R Metzler, and
I Vattulainen, Phys Rev X 6, 021006 (2016).
[4] AV Weigel, B Simon, MM Tamkun, and D Krapf, Proc Natl Acad Sci USA 108,
6438 (2011).
[5] AV Chechkin, F Seno, R Metzler, and IM Sokolov, Phys Rev X 7, 021002 (2017);
TJ Lampo, S Stylianidou, MP Backlund, PA Wiggins, AJ Spakowitz, Biophys J
112, 532 (2017).
[6] R Metzler, J-H Jeon, AG Cherstvy, E Barkai, Phys Chem Chem Phys 16 24128
(2014); JHP Schulz, E Barkai, R Metzler, Phys Rev X 4, 011028 (2014).
Primary author
Prof.
Ralf Metzler
(University of Potsdam)
