Cationic lipids bearing succinic-based, acyclic and macrocyclic hydrophobic domains: Synthetic studies and in vitro gene transfer.

In this communication we describe the construction of four succinic-based cationic lipids, their formulation with plasmid DNA (pDNA), and an evaluation of their in vitro gene delivery into Chinese hamster ovarian (CHO-K1) cells. The cationic lipids employed in this work possess either a dimethylamine or trimethylamine headgroup, and a macrocyclic or an acyclic hydrophobic domain composed of, or derived from two 16-atom, succinic-based acyl chains. The synthesized lipids and a co-lipid of neutral charge, either cholesterol or 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), were formulated in an overall 3:2 cationic-to-neutral lipid molar ratio, then complexed with plasmid DNA (pDNA).

Next generation macrocyclic and acyclic cationic lipids for gene transfer: Synthesis and in vitro evaluation.

Previously we reported the synthesis and in vitro evaluation of four novel, short-chain cationic lipid gene delivery vectors, characterized by acyclic or macrocyclic hydrophobic regions composed of, or derived from, two 7-carbon chains. Herein we describe a revised synthesis of an expanded library of related cationic lipids to include extended chain analogues, their formulation with plasmid DNA (pDNA) and in vitro delivery into Chinese hamster ovarian (CHO-K1) cells. The formulations were evaluated against each other based on structural differences in the hydrophobic domain and headgroup.

Novel cationic polyene glycol phospholipids as DNA transfer reagents--lack of a structure-activity relationship due to uncontrolled self-assembling processes.

Cationic glycol phospholipids were synthesized introducing chromophoric, rigid polyenoic C20:5 and C30:9 chains next to saturated flexible alkyl chains of variable lengths C6-20:0. Surface properties and liposome formation of the amphiphilic compounds were determined, the properties of liposome/DNA complexes (lipoplexes) were established using three formulations (no co-lipid, DOPE as a co-lipid, or cholesterol as a co-lipid), and the microstructure of the best transfecting compounds inspected using small angle X-ray diffraction to explore details of the partially ordered structures of the systems that constitute the series. Transfection and cytotoxicity of the lipoplexes were evaluated by DNA delivery to Chinese hamster ovary (CHO-K1) cells using the cationic glycerol phospholipid 1,2-dioleoyl-sn-glycero-3-ethylphosphocholine (EPC) as a reference compound.

In situ XAS and IR studies on Cu:SAPO-5 and Cu:SAPO-11: the contributory role of monomeric linear copper(i) species in the selective catalytic reduction of NOx by propene.

Cu:SAPO-5 and Cu:SAPO-11 were prepared by conventional and hydrothermal ion exchange. Copper incorporation is increased six-fold by hydrothermal ion exchange relative to conventional methods. In all cases, the amount of copper taken up by SAPO-11 is superior to uptake in SAPO-5.

Nanophase cobalt, nickel and zinc ferrites: synchrotron XAS study on the crystallite size dependence of metal distribution.

Nanophase cobalt, nickel and zinc ferrites, in which the crystallites are in the size range 4-25 nm, were synthesised by coprecipitation and subsequent annealing. X-Ray absorption spectroscopy using synchrotron radiation (supported by X-ray powder diffraction) was used to study the effects of particle size on the distributions of the metal atoms over the tetrahedral and octahedral sites of the spinel structure. Deviations from the bulk structure were found which are attributed to the significant influence of the surface on very small particles.