Structure and dynamics of lipoplex formation examined using two-photon fluorescence cross-correlation spectroscopy.
The conditions required to form transfectable lipoplexes have been extensively studied [Zuhorn, I. S., and Hoekstra, D. (2002) J. Membr. Biol. 189, 167-179]. However, to date, experiments have not addressed either the order of events of lipoplex formation in solution or the maximum number of DNA molecules per vesicle in stable single-vesicle lipoplexes. In this study, we have employed two-photon excitation fluorescence correlation spectroscopy (TPE-FCS) and two-photon fluorescence cross-correlation spectroscopy (TPE-XCS) to examine both fluorescence-labeled DNA and cationic vesicle structure and dynamics simultaneously. The dependence of large aggregated lipoplex formation on DNA-to-cationic lipid charge ratio was determined, as was the maximum number of 40 bp double-stranded DNA oligonucleotides able to bind to a single vesicle.
Merkle
Dennis
D
Department of Chemistry, University of Calgary, 2500 University Drive, NW, Calgary, Alberta T2N 1N4, Canada.
Lees-Miller
Susan P
SP
Cramb
David T
DT
D004247:DNA / Q000737:chemistry*; D005229:Fatty Acids, Monounsaturated / Q000737:chemistry; D019793:Fluorescein / Q000737:chemistry; D008081:Liposomes / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D013050:Spectrometry, Fluorescence / Q000379:methods*
D005229:Fatty Acids, Monounsaturated; D008081:Liposomes; D000644:Quaternary Ammonium Compounds; D004247:DNA; C070046:1,2-dioleoyloxy-3-(trimethylammonium)propane; D019793:Fluorescein