Biophysical characterization of an integrin-targeted lipopolyplex gene delivery vector.
Nonviral gene delivery vectors now show good therapeutic potential: however, detailed characterization of the composition and macromolecular organization of such particles remains a challenge. This paper describes experiments to elucidate the structure of a ternary, targeted, lipopolyplex synthetic vector, the LID complex. This consists of a lipid component, Lipofectin (L) (1:1 DOTMA:DOPE), plasmid DNA (D), and a dual-function, cationic peptide component (I) containing DNA condensation and integrin-targeting sequences. Fluorophore-labeled lipid, peptide, and DNA components were used to formulate the vector, and the stoichiometry of the particles was established by fluorescence correlation spectroscopy (FCS). The size of the complex was measured by FCS, and the sizes of LID, L, LD, and ID complexes were measured by dynamic light scattering (DLS). Fluorescence quenching experiments and freeze-fracture electron microscopy were then used to demonstrate the arrangement of the lipid, peptide, and DNA components within the complex. These experiments showed that the cationic portion of the peptide, I, interacts with the plasmid DNA, resulting in a tightly condensed DNA-peptide inner core; this is surrounded by a disordered lipid layer, from which the integrin-targeting sequence of the peptide partially protrudes.
Mustapa
M Firouz Mohd
MF
Department of Chemistry, Christopher Ingold Laboratories, University College London, United Kingdom.
Bell
Paul C
PC
Hurley
Christopher A
CA
Nicol
Alastair
A
Guénin
Erwann
E
Sarkar
Supti
S
Writer
Michele J
MJ
Barker
Susie E
SE
Wong
John B
JB
Pilkington-Miksa
Michael A
MA
Papahadjopoulos-Sternberg
Brigitte
B
Shamlou
Parviz Ayazi
PA
Hailes
Helen C
HC
Hart
Stephen L
SL
Zicha
Daniel
D
Tabor
Alethea B
AB
D055592:Biophysical Phenomena; D001703:Biophysics; D004247:DNA / Q000737:chemistry; D004058:Diffusion; D005614:Freeze Fracturing; D005822:Genetic Vectors; D016023:Integrins; D008027:Light; D008081:Liposomes / Q000138:chemical synthesis; D008854:Microscopy, Electron; D010714:Phosphatidylethanolamines / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D012542:Scattering, Radiation; D013050:Spectrometry, Fluorescence
D016023:Integrins; D008081:Liposomes; D010714:Phosphatidylethanolamines; D000644:Quaternary Ammonium Compounds; C054005:N-(1-(2,3-dioleyloxy)propyl)-N,N,N-trimethylammonium; C094877:dioleoyl phosphatidylethanolamine; C020888:1,2-dielaidoylphosphatidylethanolamine; D004247:DNA