TY - JOUR
T1 - Polyplex formation influences release mechanism of mono- and di-valent ions from phosphorylcholine group bearing hydrogels
AU - Wilson, A. Nolan
AU - Blenner, Mark
AU - Guiseppi-Elie, Anthony
N1 - Publisher Copyright:
© 2014 by the authors.
PY - 2014
Y1 - 2014
N2 - The release of monovalent potassium and divalent calcium ions from zwitterionic phosphorylcholine containing poly(2-hydroxyethyl methacrylate) (pHEMA)-based hydrogels was studied and the effects of polymer swelling, ion valence and temperature were investigated. For comparison, ions were loaded during hydrogel formulation or loaded by partitioning following construct synthesis. Using the Koshmeyer-Peppas release model, the apparent diffusion coefficient, Dapp, and diffusional exponents, n, were Dapp (pre-K+) = 2.03 × 10-5, n = 0.4 and Dapp (post-K+) = 1.86 × 10-5, n = 0.33 respectively, indicative of Fickian transport. The Dapp (pre-Ca2+) = 3.90 × 10-6, n = 0.60 and Dapp (post-Ca2+) = 2.85 × 10-6, n = 0.85, respectively, indicative of case II and anomalous transport. Results indicate that divalent cations form cation-polyelectrolyte anion polymer complexes while monovalent ions do not. Temperature dependence of potassium ion release was shown to follow an Arrhenius-type relation with negative apparent activation energy of -19 ± 15 while calcium ion release was temperature independent over the physiologically relevant range (25-45 °C) studied. The negative apparent activation energy may be due to temperature dependent polymer swelling. No effect of polymer swelling on the diffusional exponent or rate constant was found suggesting polymer relaxation occurs independent of polymer swelling.
AB - The release of monovalent potassium and divalent calcium ions from zwitterionic phosphorylcholine containing poly(2-hydroxyethyl methacrylate) (pHEMA)-based hydrogels was studied and the effects of polymer swelling, ion valence and temperature were investigated. For comparison, ions were loaded during hydrogel formulation or loaded by partitioning following construct synthesis. Using the Koshmeyer-Peppas release model, the apparent diffusion coefficient, Dapp, and diffusional exponents, n, were Dapp (pre-K+) = 2.03 × 10-5, n = 0.4 and Dapp (post-K+) = 1.86 × 10-5, n = 0.33 respectively, indicative of Fickian transport. The Dapp (pre-Ca2+) = 3.90 × 10-6, n = 0.60 and Dapp (post-Ca2+) = 2.85 × 10-6, n = 0.85, respectively, indicative of case II and anomalous transport. Results indicate that divalent cations form cation-polyelectrolyte anion polymer complexes while monovalent ions do not. Temperature dependence of potassium ion release was shown to follow an Arrhenius-type relation with negative apparent activation energy of -19 ± 15 while calcium ion release was temperature independent over the physiologically relevant range (25-45 °C) studied. The negative apparent activation energy may be due to temperature dependent polymer swelling. No effect of polymer swelling on the diffusional exponent or rate constant was found suggesting polymer relaxation occurs independent of polymer swelling.
KW - Diffusional exponent
KW - Electromigration
KW - Hydrogels
KW - Polyplexes
KW - Release
KW - Transport
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U2 - 10.3390/polym6092451
DO - 10.3390/polym6092451
M3 - Article
AN - SCOPUS:84910050845
VL - 6
SP - 2451
EP - 2472
JO - Polymers
JF - Polymers
SN - 2073-4360
IS - 9
ER -