• We are sorry, but NCBI web applications do not support your browser and may not function properly. More information
Logo of biophysjLink to Publisher's site
Biophys J. Jul 1991; 60(1): 179–189.
PMCID: PMC1260049

Quantitation of lipid phases in phospholipid vesicles by the generalized polarization of Laurdan fluorescence.


The sensitivity of Laurdan (6-dodecanoyl-2-dimethylaminonaphthalene) excitation and emission spectra to the physical state of the membrane arises from dipolar relaxation processes in the membrane region surrounding the Laurdan molecule. Experiments performed using phospholipid vesicles composed of phospholipids with different polar head groups show that this part of the molecule is not responsible for the observed effects. Also, pH titration in the range from pH 4 to 10 shows that the spectral variations are independent of the charge of the polar head. A two-state model of dipolar relaxation is used to qualitatively explain the behavior of Laurdan. It is concluded that the presence of water molecules in the phospholipid matrix are responsible for the spectral properties of Laurdan in the gel phase. In the liquid crystalline phase there is a relaxation process that we attribute to water molecules that can reorientate during the few nanoseconds of the excited state lifetime. The quantitation of lipid phases is obtained using generalized polarization which, after proper choice of excitation and emission wavelengths, satisfies a simple addition rule.

Full text

Full text is available as a scanned copy of the original print version. Get a printable copy (PDF file) of the complete article (1.7M), or click on a page image below to browse page by page. Links to PubMed are also available for Selected References.

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Whitesell RR, Regen DM, Beth AH, Pelletier DK, Abumrad NA. Activation energy of the slowest step in the glucose carrier cycle: break at 23 degrees C and correlation with membrane lipid fluidity. Biochemistry. 1989 Jun 27;28(13):5618–5625. [PubMed]
  • Bigelow DJ, Thomas DD. Rotational dynamics of lipid and the Ca-ATPase in sarcoplasmic reticulum. The molecular basis of activation by diethyl ether. J Biol Chem. 1987 Oct 5;262(28):13449–13456. [PubMed]
  • Nishizuka Y. Turnover of inositol phospholipids and signal transduction. Science. 1984 Sep 21;225(4668):1365–1370. [PubMed]
  • Nishizuka Y. Studies and perspectives of protein kinase C. Science. 1986 Jul 18;233(4761):305–312. [PubMed]
  • Klausner RD, Kleinfeld AM, Hoover RL, Karnovsky MJ. Lipid domains in membranes. Evidence derived from structural perturbations induced by free fatty acids and lifetime heterogeneity analysis. J Biol Chem. 1980 Feb 25;255(4):1286–1295. [PubMed]
  • Lentz BR, Clubb KW, Alford DR, Höchli M, Meissner G. Phase behavior of membranes reconstituted from dipentadecanoylphosphatidylcholine and the Mg2+-dependent, Ca2+-stimulated adenosinetriphosphatase of sarcoplasmic reticulum: evidence for a disrupted lipid domain surrounding protein. Biochemistry. 1985 Jan 15;24(2):433–442. [PubMed]
  • Seelig J, Macdonald PM, Scherer PG. Phospholipid head groups as sensors of electric charge in membranes. Biochemistry. 1987 Dec 1;26(24):7535–7541. [PubMed]
  • Devaux PF, Seigneuret M. Specificity of lipid-protein interactions as determined by spectroscopic techniques. Biochim Biophys Acta. 1985 Jun 12;822(1):63–125. [PubMed]
  • Parasassi T, Conti F, Glaser M, Gratton E. Detection of phospholipid phase separation. A multifrequency phase fluorimetry study of 1,6-diphenyl-1,3,5-hexatriene fluorescence. J Biol Chem. 1984 Nov 25;259(22):14011–14017. [PubMed]
  • Van der Meer BW. Biomembrane structure and dynamics viewed by fluorescence. Subcell Biochem. 1988;13:1–53. [PubMed]
  • Lakowicz JR, Freshwater G, Weber G. Nanosecond segmental mobilities of tryptophan residues in proteins observed by lifetime-resolved fluorescence anisotropies. Biophys J. 1980 Oct;32(1):591–601. [PMC free article] [PubMed]
  • Ruggiero A, Hudson B. Critical density fluctuations in lipid bilayers detected by fluorescence lifetime heterogeneity. Biophys J. 1989 Jun;55(6):1111–1124. [PMC free article] [PubMed]
  • Parasassi T, De Stasio G, d'Ubaldo A, Gratton E. Phase fluctuation in phospholipid membranes revealed by Laurdan fluorescence. Biophys J. 1990 Jun;57(6):1179–1186. [PMC free article] [PubMed]
  • Chong PL. Effects of hydrostatic pressure on the location of PRODAN in lipid bilayers and cellular membranes. Biochemistry. 1988 Jan 12;27(1):399–404. [PubMed]
  • Parasassi T, Conti F, Gratton E. Time-resolved fluorescence emission spectra of Laurdan in phospholipid vesicles by multifrequency phase and modulation fluorometry. Cell Mol Biol. 1986;32(1):103–108. [PubMed]
  • Gratton E, Limkeman M. A continuously variable frequency cross-correlation phase fluorometer with picosecond resolution. Biophys J. 1983 Dec;44(3):315–324. [PMC free article] [PubMed]
  • Parasassi T, De Stasio G, Miccheli A, Bruno F, Conti F, Gratton E. Abscisic acid-induced microheterogeneity in phospholipid vesicles. A fluorescence study. Biophys Chem. 1990 Jan;35(1):65–73. [PubMed]
  • Copeland BR, Andersen HC. A theory of effect of protons and divalent cations on phase equilibria in charged bilayer membranes: comparison with experiment. Biochemistry. 1982 Jun 8;21(12):2811–2820. [PubMed]
  • Macgregor RB, Weber G. Estimation of the polarity of the protein interior by optical spectroscopy. Nature. 1986 Jan 2;319(6048):70–73. [PubMed]
  • Jendrasiak GL, Hasty JH. The electrical conductivity of hydrated phospholipids. Biochim Biophys Acta. 1974 Apr 26;348(1):45–54. [PubMed]

Articles from Biophysical Journal are provided here courtesy of The Biophysical Society


Related citations in PubMed

See reviews...See all...

Cited by other articles in PMC

See all...


  • Compound
    PubChem Compound links
  • MedGen
    Related information in MedGen
  • PubMed
    PubMed citations for these articles
  • Substance
    PubChem Substance links

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...