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 | Nanotech 2006 Vol. 2
Technical Proceedings of the 2006 NSTI Nanotechnology Conference and Trade Show, Volume 2
Chapter 5: Drug Delivery |
| | Synergistic Release of DNA from pH Responsive Polyion Complexes (PICs) | | Authors: | G. Harper | | Affilation: | WetaScience, UK | | Pages: | 381 - 383 | | Keywords: | DNA controlled release pH responsive polyion complex | | Abstract: | Polyelectrolyte complexes based on an outer layer of cationic polyhydroxylamine (PT) were prepared on carboxylated microparticles pretreated with polyamine (A) and a middle layer of Polyacrylic Acid (PA). A synergistic effect between PT and PA layers provides greater binding with release of DNA (11.5 µg/mg, 0.36se) on pH change compared to PT adsorbed without a supporting polyanion (7.95 µg/mg, 0.38se). Historically polyelectrolyte complexes formed in solution between polyions of opposite charge, polycations and polyanions, were considered to be largely stoichiometric in structure1. More recent evidence suggests that non-stoichiometry occurs within PECs according to formulation conditions2. The formation of PEC multilayers or nanolayers on substrates is now receiving attention3. Our development of a polycationic polyhydroxylamine with a pKa below 9 allows the synthesis of alternating polyion layers on a magnetic bead substrate . These beads have the capability to bind polyanionic DNA at low pH (4) and elution at a moderate pH(8), with obvious utility in isolation and purification of DNA in aqueous media.
pH dependent DNA binding and elution from polyhydroxylamine [PT] containing PECs is described. Significantly greater binding and subsequent release of DNA is achieved by PT, as a PEC, than as a simply adsorbed polycation (Fig 6.). Synergism exists between anionic PA, as a supporting layer, and cationic PT providing a significant increase in DNA binding and elution (11.6 (0.4se) vs 7.9 (0.4se) µgDNA/mg beads) . Polyanion and polycation layer presence is confirmed by both zeta potential and dye binding results. NR dye recovery from PA with PT present (C/AF/PA/PT) provides evidence that the electrosteric architecture of each polyion layer is largely conserved between adjacent polyion layers. | | ISBN: | 0-9767985-7-3 |
| Pages: | 893 |
| Hardcopy: | $185.00 |
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