Cationic Nanoparticles based on pH Responsive Polyion Complexes containing Plasmid GFP DNA



Cationic nanoparticles were formulated from a polycationic Polyhydroxylamine (PT) with low pKa and polyanionic PolyAcrylic Acid (PA) that form binary polyelectrolyte complexes (PECs). Particles spontaneously form on component mixing with sizes between 80-700nm and particle charge 3-30mV. Plasmid containing GFP (pGFP), was incorporated by prebinding pGFP to PT and assessed by Agarose gel electrophoresis.
Nanoparticle polymer systems below 1 micron in size have potential roles as carrier systems in fields of biotechnology and emerging nanotechnology.
Recent advances in understanding the physico-chemical structure of PECs has rekindled interest in their application to various fields1,2. We describe here the formulation of nanoparticles based on a polycation, Polyhydroxyl-amine (PT), with PA as a model polyanion to form binary polyelectrolyte complexes (PECs). Plasmid containing Green Fluorescence Protein (pGFP) DNA was also incorporated as a carried gene (polyanion) within the PEC nanoparticle. An advantage of using polyhydroxlamine based PECs is that they should allow release of bound DNA as a polyanion from a PEC at relatively mild pH conditions, due to the low pKa (below 9) of the PT. Such nanoparticles have potential use as cationic transfection agents that can release under benign physiological conditions compared to similar particles formulated with ‘hard’ polyamines with higher pKa (>pH9). Simple addition of polyhydroxylamine and poly-acrylic acid (w/w), under mildly acidic conditions, causes spontaneous formation of cationic nanoparticulate PEC dispersions with a range of size (80 and 700 nm), and charge (4-30mV).
Vector of addition, as PA to PT or PT to PA, influences particle size and charge. Addition of further polyhydroxylamine to particles formed as PA added to PT results in reduced zeta potential (+17.7 to +2.7 mV). Plasmid GFP can be incorporated into the particle by prebinding pGFP to the polyhydroxylamine before PEC formation.

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Journal: TechConnect Briefs
Volume: 2, Technical Proceedings of the 2006 NSTI Nanotechnology Conference and Trade Show, Volume 2
Published: May 7, 2006
Pages: 370 - 372
Industry sector: Medical & Biotech
Topics: Biomaterials, Materials for Drug & Gene Delivery
ISBN: 0-9767985-7-3