Polyion complex micelles as vectors in gene therapy - Pharmacokinetics and in vivo gene transfer

Division of New Materials Science, The University of Tokyo, 白山, Tōkyō, Japan
Gene Therapy (Impact Factor: 3.1). 04/2002; 9(6):407-14. DOI: 10.1038/
Source: PubMed


To establish non-viral gene delivery systems for intravenous administration, complexes of DNA and block copolymer consisting of poly-L-lysine and poly(ethylene glycol) were tested in in vivo turnover studies. The polyion complex micelles have self-assembling core-shell structures, yielding spherical nano-particles with small absolute values of zeta-potential. Southern blot analysis showed that supercoiled DNA was observed for 30 min and open circular or linear DNA was seen for 3 h after intravenous administration of PIC micelles having the charge ratios of 1:4 and PLL length of 48 mer. The PIC micelles with shorter PLL length showed lower stability in the blood stream suggesting that DNA is able to persist as an intact molecule in the blood stream using this system. Though having no ligands, PIC micelles with charge ratios of 1:2 and 1:4 transfected efficiently into HepG2 cells. Preincubation with free copolymer inhibited expression of the reporter gene, suggesting that adsorption of block copolymer to the cell surface blocked the interaction site of the PIC micelles. When the PIC micelles were injected via supramesenteric vein, expression of the gene was observed only in the liver and was sustained for 3 days. It was suggested that this gene delivery system is intrinsically efficient.

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Available from: Kazunori Kataoka, Jun 21, 2014
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    • "Indeed, the use of polymers that are biodegradable or can release their cargo in response to welldefined stimuli, enables small molecule drugs to be delivered over an extended period of time, thus achieving effective therapeutic effects at reduced drug concentrations or dosage frequency [7] [8] [9]. Due to their versatility in templating and surface coating, several polymeric nanosystems such as polyelectrolyte capsules [10] [11] [12], polyionic complexes (PICs), or polyelectrolyte complexes (PECs) are being largely characterized by addressing their uptake kinetics and processing in living human cells [13] [14] [15] [16]. "
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    ABSTRACT: This pilot study provides the proof of principle for biomedical application of novel polyelectrolyte complexes (PECs) obtained via electrostatic interactions between dextran sulphate (DXS) and poly(allylamine hydrochloride) (PAH). Scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed that DXS/PAH polyelectrolyte complexes were Monodispersed with regular rounded-shape features and average diameters of 250 nm at 2 : 1 weight ratios of DXS/PAH. Fluorescently labelled DXS and fluorescein-isothiocyanate- (FITC-)conjugate DXS were used to follow cell uptake efficiency of PECs and biodegradability of their enzymatically degradable DXS-layers by using confocal laser scanning microscopy (CLSM). Moreover, quantitative MTT and Trypan Blue assays were employed to validate PECs as feasible and safe nanoscaled carriers at single-cell level without adverse effects on metabolism and viability.
    Full-text · Article · Aug 2011
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    • "Copolymers with one PEG block and another cationic block such as poly(L-lysine) (PLL) and polyaspartamides, have been employed by Kataoka and coworkers for the delivery of DNAs or siRNAs [95] [96] [97]. Both in vitro and in vivo results have demonstrated their usefulness for gene therapy [98] [99] [100] [101]. Other cationic polymers such as polyethyleneimine (PEI), polyspermine, poly(N-[3-(dimethylamino)propyl]methacrylamide) (PDM- APMA), cyclodextrin containing polycations, polypeptides, poly(-amino esters), chitosan and its derivatives were also employed as cationic block/segment [102] [103] [104] [105] [106] [107] [108] [109] [110]. "
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    ABSTRACT: Multi-morphologic polymer nano-assemblies, such as micelles and vesicles, have been intensively studied recently by scientists in the multidisciplinary fields for their promising applications in bioengineering, biomedicine and pharmaceutics. With the success of several micellar formulations in clinical trials, more and more therapeutics based on polymer assemblies are on the pipeline for clinical applications. The current review summarizes some recent patents on the polymer nano-assemblies including micelles and vesicles, with the focus on drug delivery and gene therapy. For the lack of updated patents, the selected progress made most recently in this field has been presented based on the newly published articles. The future development in this active and exciting field has been discussed as well. Because of the huge literature of scientific papers on delivery systems based on polymer assemblies in recent years, this review attempts to limit the specific examples to those that are currently in clinical trials. Accordingly, it is impossible to properly credit all the scientists in this field. The author apologizes in advance for all omissions.
    Full-text · Article · Nov 2009
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    • "It self-assembled in aqueous solution to form tri-layered cationic micellar nanoparticles (MNPs) that were capable for efficient siRNA delivery (Scheme 1). The rationale behind the choice of PCL block is hydrophobic interaction between PCL segments which induces the micellar core formation and stabilizes the nanoparticles [34] [35], while hydrophilic poly(ethylene glycol) (PEG) is also potential to protect siRNA and extend blood circulation for systemic administration [29] [36] [37]. On the other hand, positively charged poly(2-aminoethyl ethylene phosphate ) (PPEEA) block, which is biocompatible and degradable [38] [39], is served as siRNA binding site and expected to release siRNA. "
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    ABSTRACT: A novel amphiphilic and cationic triblock copolymer consisting of monomethoxy poly(ethylene glycol), poly(epsilon-caprolactone) (PCL) and poly(2-aminoethyl ethylene phosphate) denoted as mPEG(45)-b-PCL(100)-b-PPEEA(12) was designed and synthesized for siRNA delivery. The copolymers were well characterized by (1)H NMR spectroscopy and gel permeation chromatography. Micelle nanoparticles' (MNPs) formation of this amphiphilic copolymer in aqueous solution was studied by dynamic light scattering, transmission electron microscopy and fluorescence technique. MNPs took uniform spherical morphology with zeta potential of around 45 mV and were stabilized by hydrophobic-hydrophobic interaction in the PCL core, exhibiting the critical micelle concentration at 2.7 x 10(-3) mg/mL. Such MNPs allowed siRNA loading post nanoparticle formation without change in uniformity. The average diameter of nanoparticles after siRNA binding ranged from 98 to 125 nm depending on N/P ratios. The siRNA loaded nanoparticles can be effectively internalized and subsequently release siRNA in HEK293 cells, resulting in significant gene knockdown activities, which was demonstrated by delivering two siRNAs targeting green fluorescence protein (GFP). It effectively silenced GFP expression in 40-70% GFP-expressed HEK293 cells and it was observed that higher N/P ratio resulted in more effective silence which was likely due to better cell internalization at higher N/P ratio. MTT assay demonstrated that neither MNPs themselves nor siRNA loaded MNPs showed cytotoxicity even at high concentrations. Such cationic MNPs made from biocompatible and biodegradable polymers are promising for siRNA delivery.
    Full-text · Article · Dec 2008 · Biomaterials
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