title: Limitations of electronic energy transfer in the determination of lipid nanodomain sizes.
abstract: Even though superresolution microscopy indicates that size of plasma membrane rafts is <20 nm, those structures have never been observed. Förster resonance energy transfer (FRET) is therefore still the most powerful optical method for characterization of such domains. In this letter we investigate relation between nanodomain affinity of a donor-acceptor (D/A) pair and the detectable nanodomain size/area. We show that probes with high affinity to the liquid-ordered (L(o)) phase are required for detecting domain sizes of a few nanometers, and/or domains that occupy a few percent of the bilayer area. A combination of donors and acceptors that prefer different phases is the more favorable approach. For instance, a D/A pair with the distribution constant of donors K(D) = 5 and acceptors K(A) = 0.01 can resolve a broad spectrum of nanodomain sizes. On the other hand, currently available donors and acceptors that prefer the same phase, either the liquid-disordered (L(d)) or L(o) phase, are not so convenient for determining domain sizes <20 nm. Here the detection limits of FRET experiments employing several commonly used D/A pairs have been investigated.
authors.affiliation: J. Heyrovský Institute of Physical Chemistry, v.v.i., Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: Radek
authors.initials: R
authors.lastname: Sachl
authors.forename: Jana
authors.initials: J
authors.lastname: Humpolíčková
authors.forename: Martin
authors.initials: M
authors.lastname: Stefl
authors.forename: Lennart B-Å
authors.initials: LB
authors.lastname: Johansson
authors.forename: Martin
authors.initials: M
authors.lastname: Hof
mesh_terms: D001896:Boron Compounds / Q000737:chemistry; D002232:Carbocyanines / Q000737:chemistry; D002772:Cholera Toxin / Q000737:chemistry; D004583:Electrons; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D008051:Lipid Bilayers / Q000737:chemistry*; D021962:Membrane Microdomains / Q000737:chemistry*; D009010:Monte Carlo Method; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D010569:Perylene / Q000737:chemistry; D010799:Phycoerythrin / Q000737:chemistry; D015203:Reproducibility of Results; D012235:Rhodamines / Q000737:chemistry; D013997:Time Factors
chemical_list: C095489:4,4-difluoro-4-bora-3a,4a-diaza-s-indacene; C569686:Alexa Fluor 647; D001896:Boron Compounds; D002232:Carbocyanines; D008051:Lipid Bilayers; D012235:Rhodamines; D010799:Phycoerythrin; D010569:Perylene; D002772:Cholera Toxin