Fluorescence correlation spectroscopy diffusion laws in the presence of moving nanodomains

0457556 - ÚFCH JH 2017 RIV GB eng J - Článek v odborném periodiku
Šachl, Radek - Bergstrand, J. - Widengren, J. - Hof, Martin
Fluorescence correlation spectroscopy diffusion laws in the presence of moving nanodomains.
Journal of Physics D-Applied Physics. Roč. 49, č. 11 (2016), 114002. ISSN 0022-3727. E-ISSN 1361-6463
Grant CEP: GA ČR(CZ) GC14-03141J
Institucionální podpora: RVO:61388955
Klíčová slova: FCS * lipid nanodomains * anomalous diffusion
Kód oboru RIV: CF - Fyzikální chemie a teoretická chemie
Impakt faktor: 2.588, rok: 2016

It has been shown by means of simulations that spot variation fluorescence correlation/nspectroscopy (sv-FCS) can be used for the identification and, to some extent, also/ncharacterization of immobile lipid nanodomains in model as well as cellular plasma/nmembranes. However, in these simulations, the nanodomains were assumed to be stationary,/nwhereas they actually tend to move like the surrounding lipids. In the present study, we/ninvestigated how such domain movement influences the diffusion time/spot-size dependence/nobserved in FCS experiments, usually referred to as ‘diffusion law’ analysis. We show/nthat domain movement might mask the effects of the ‘anomalous’ diffusion characteristics/nof membrane lipids or proteins predicted for stationary domains, making it difficult to/nidentify such moving nanodomains by sv-FCS. More specifically, our simulations indicate/nthat (i) for domains moving up to a factor of 2.25 slower than the surrounding lipids, such/nimpeded diffusion cannot be observed and the diffusion behaviour of the proteins or lipids is/nindistinguishable from that of freely diffusing molecules, i.e. nanodomains are not detected;/n(ii) impeded protein/lipid diffusion behaviour can be observed in experiments where the radii/nof the detection volume are similar in size to the domain radii, the domain diffusion is about/n10 times slower than that of the lipids, and the probes show a high affinity to the domains;/nand (iii) presence of nanodomains can only be reliably detected by diffraction limited sv-FCS/nwhen the domains move very slowly (about 200 times slower than the lipid diffusion). As/nnanodomains are expected to be in the range of tens of nanometres and most probes show/nlow affinities to such domains, sv-FCS is limited to stationary domains and/or STED-FCS./nHowever, even for that latter technique, diffusing domains smaller than 50 nm in radius are/nhardly detectable by FCS diffusion time/spot-size dependencies.
Trvalý link: http://hdl.handle.net/11104/0258006