title: Physicochemical and biological characterization of 1,2-dialkoylamidopropane-based lipoplexes for gene delivery.
abstract: Elucidation of the molecular and formulation requirements for efficient lipofection is a prerequisite to enhance the biological activity of cationic lipid-mediated gene delivery systems. To this end, the in vitro lipofection activity of the ionizable asymmetric 1,2-dialkoylamidopropane-based derivatives bearing a single primary amine group as the cationic head group was evaluated. The electrostatic interactions of these cationic lipids with plasmid DNA in serum-free medium were investigated by means of gel electrophoresis retardation and Eth-Br quenching assays. The effect of the inclusion of the helper lipid DOPE in the formulation on these interactions was also considered. The physicochemical properties of these lipids in terms of bilayer fluidity and extent of ionization were investigated using fluorescence anisotropy and surface potential techniques, respectively. The results showed that only the active lipid, 1,2lmp[5], existed in a liquid crystalline state at physiological temperature. Moreover, the extent of ionization of this lipid in assemblies was significantly higher that it's saturated analogues. Inclusion of the helper lipid DOPE improved the encapsulation and association between 1,2lmp[5] and plasmid DNA, which was reflected by the significant boost of lipofection activity of the 1,2lmp[5]/DOPE formulation as compared to the lipid alone. In conclusion, membrane fluidity and sufficient protonation of ionizable cationic lipid are required for efficient association and encapsulation of plasmid DNA and elicit of improved in vitro lipofection activity.
authors.affiliation: Department of Pharmaceutical Sciences and Pharmaceutics, Faculty of Pharmacy, Applied Science University, P.O. Box 926296, Amman 11931, Jordan. Electronic address: aljaberi@asu.edu.jo.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Aljaberi
authors.affiliation: Department of Pharmaceutical Sciences and Pharmaceutics, Faculty of Pharmacy, Applied Science University, P.O. Box 926296, Amman 11931, Jordan.
authors.forename: Suhair
authors.initials: S
authors.lastname: Saleh
authors.affiliation: Department of Biological Sciences, Faculty of Science, Yarmouk University, P.O. Box 566, Irbid 21163, Jordan.
authors.forename: Khalid M
authors.initials: KM
authors.lastname: Abu Khadra
authors.affiliation: Biology Faculty, Concordia College, 171 White Plains Road, Bronxville, NY 10708, USA.
authors.forename: Molinda
authors.initials: M
authors.lastname: Kearns
authors.affiliation: Division of Pharmaceutical Sciences, Arnold & Marie Schwartz College of Pharmacy & Health Sciences, Long Island University, Brooklyn, NY, USA.
authors.forename: Michalakis
authors.initials: M
authors.lastname: Savva
mesh_terms: D002412:Cations; D055598:Chemical Phenomena; D003102:Colloids / Q000737:chemistry; D004587:Electrophoresis, Agar Gel; D018014:Gene Transfer Techniques; D008081:Liposomes / Q000737:chemistry*; D015394:Molecular Structure; D011407:Propane / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism
chemical_list: D002412:Cations; D003102:Colloids; D008081:Liposomes; D011407:Propane
keywords: Cationic lipids; Fluorescence anisotropy; Gene delivery; Lipofection; Membrane fluidity; Surface potential