The effect of intercalants on the host liposome

Yael Cohen, Hana Weitman, Michal Afri, Rinat Yanus, Safra Rudnick, Yeshayahu Talmon, Judith Schmidt, Pinchas Aped, Smadar Shatz, Benjamin Ehrenberg, Aryeh A. Frimer

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

When phospholipids are vigorously dispersed in water, liposomes are formed. In the present study, we have explored the effect of intercalant concentration on various properties of unilamellar liposomes. Liposomes were sonically intercalated with vitamin E acetate (VitEAc) and hypericin (Hy) until no difference in light transmission was observed, which reflects the formation of liposomes of minimal diameter. Our studies indicate that the intercalant structure and concentration have an influence on the liposome diameter, which could be directly measured by cryogenic transmittance electronic microscopy. Thus, intercalated VitEAc substantially decreased the diameter of unilamellar dimyristoylphosphatidylcholine liposomes, whereas Hy did not. In addition, we followed peak intensities in the absorbance and fluorescence spectra of Hy as a function of intercalant concentration in the liposomal solution. Initially, the fluorescence intensity increased linearly with concentration; however, the curve then arched asymptotically, followed by a decrease in fluorescence at yet higher concentrations. Because the Hy monomer is the only species that emits fluorescence, we believe that the decrease of fluorescence intensity is the result of Hy aggregation.

Original languageEnglish
Pages (from-to)306-318
Number of pages13
JournalJournal of Liposome Research
Volume22
Issue number4
DOIs
StatePublished - Dec 2012

Bibliographical note

Funding Information:
The authors acknowledge the kind and generous support of The Israel Science Foundation (grant nos.: 327/02 and 437/06), founded by The Israel Academy of Sciences and Humanities, and The Ethel and David Resnick Chair in Active Oxygen Chemistry at Bar-Ilan University.

Funding

The authors acknowledge the kind and generous support of The Israel Science Foundation (grant nos.: 327/02 and 437/06), founded by The Israel Academy of Sciences and Humanities, and The Ethel and David Resnick Chair in Active Oxygen Chemistry at Bar-Ilan University.

FundersFunder number
Israel Academy of Sciences and Humanities
Israel Science Foundation327/02, 437/06

    Keywords

    • Cryo-TEM
    • Fluorescence
    • Hypericin
    • NMR
    • Vitamin E acetate

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