Stabilized plasmid-lipid particles for systemic gene therapy

Abstract

The structure of 'stabilized plasmid-lipid particles' (SPLP) and their properties as systemic gene therapy vectors has been investigated. We show that SPLP can be visualized employing cryo-electron microscopy to be homogeneous particles of diameter 72 ± 5 nm consisting of a lipid bilayer surrounding a core of plasmid DNA. It is also shown that SPLP exhibit long circulation lifetimes (circulation half-life Ͼ6 h) following intravenous (i.v.) injection in a murine tumor model resulting in accumulation of up to 3% of the total injected dose and concomitant reporter gene expression at a distal (hind flank) tumor site. In contrast, i.v. injection of

Optimized cationic lipid‐based gene delivery reagents for use in developing vertebrate embryos

“…To solve these problems, we chose a detergent dialysis technique to form our lipoplexes, minimizing degradation and clearance of the plasmid as well as aggregation of the lipoplexes. Detergent dialysis has been shown to efficiently encapsulate plasmid DNA in small, serum-stable lipoplexes, even at high DNA concentrations and high lipid-plasmid charge ratios ( (Hofland et al, 1996(Hofland et al, , 1997Wheeler et al, 1999;Tam et al, 2000).…”

Ultrasound assisted siRNA delivery using PEG-siPlex loaded microbubbles

“…A common approach for reducing these undesired interactions is by masking the cationic surface of the nanoparticles with hydrophilic polymers, such as polyethylene glycol (PEG). This prevents the aggregation of these nucleic acid containing nanoparticles in blood and prolongs their circulation time [17][18][19][20]. However, it has been observed by many groups that shielding the surface of non-viral gene delivery systems with polymers like PEG leads to a drastic reduction in gene transfer, due to a reduced cellular uptake or limited endosomal release [21,22].…”

A pH-sensitive cationic lipid facilitates the delivery of liposomal siRNA and gene silencing activity in vitro and in vivo

“…Sterically stabilization of a lipid based nano carrier by poly(ethyleneglycol) (PEG) is the most popular method and is widely used to enhance circulation time by reducing nonspecific interaction between positively charged nano carriers and negatively charged serum components, leading to severe aggregation and rapid clearance from circulation by the reticuloendothelial system [16]. However, it is well-known that PEGylation leads to a severe decline of cellular uptake via endocytosis and the endosomal escape process of nano carriers, which results in the loss of efficacy for delivering siRNA into the cytoplasm [17,18].…”