Dual responsive composite hydrogelswere successfully prepared by combining cellulosenanofibril (CNF) isolated by 2,2,6,6-tetram-ethylpiperidine-1-oxyl radical (TEMPO)-mediatedoxidation with thermally responsive poly(N-isopropy-lacrylamide) (PNIPAAm) for drug release at 10 wt%CNF loading and-20°C polymerization tempera-ture. pH responsive hydrogels were acquired byadjusting the carboxyl charge level of the CNF duringTEMPO-mediated oxidation. CNF–PNIPAAm hydro-gels fabricated were characterized in regards tocompressive strength, functional group, low criticalsolution temperature (LCST), and swelling ratio of thehydrogels at different temperatures from 20 to 60°Cand pH levels from 2 to 10. Finally, the drug releasebehavior of these hydrogels was also investigatedusing methylene blue as a model drug. As thecarboxylate content increases, the dual responsivenessof hydrogel improved at the expense of the compres-sion strength. The CNF–PNIPAAm hydrogels wereswollen and translucent below the LCST, and shrunkenand opaque above the LCST. The Higuchi and theKrosmeyer and Peppas model was best-fitted to thedrug release behavior of these hydrogels at pH 10 andpH 2, respectively. The results also indicated that aproper selection of polymerization temperature pro-vided a way of tuning the dual-responsiveness of thehydrogels. These results also suggest that the CNF–PNIPAAm hydrogels can release drugs on demand.
Dual-responsive composite hydrogels based on TEMPO-oxidized cellulose nanofibril and poly(N-isopropylacrylamide) for model drug release
Causin, Valerio
2018
Abstract
Dual responsive composite hydrogelswere successfully prepared by combining cellulosenanofibril (CNF) isolated by 2,2,6,6-tetram-ethylpiperidine-1-oxyl radical (TEMPO)-mediatedoxidation with thermally responsive poly(N-isopropy-lacrylamide) (PNIPAAm) for drug release at 10 wt%CNF loading and-20°C polymerization tempera-ture. pH responsive hydrogels were acquired byadjusting the carboxyl charge level of the CNF duringTEMPO-mediated oxidation. CNF–PNIPAAm hydro-gels fabricated were characterized in regards tocompressive strength, functional group, low criticalsolution temperature (LCST), and swelling ratio of thehydrogels at different temperatures from 20 to 60°Cand pH levels from 2 to 10. Finally, the drug releasebehavior of these hydrogels was also investigatedusing methylene blue as a model drug. As thecarboxylate content increases, the dual responsivenessof hydrogel improved at the expense of the compres-sion strength. The CNF–PNIPAAm hydrogels wereswollen and translucent below the LCST, and shrunkenand opaque above the LCST. The Higuchi and theKrosmeyer and Peppas model was best-fitted to thedrug release behavior of these hydrogels at pH 10 andpH 2, respectively. The results also indicated that aproper selection of polymerization temperature pro-vided a way of tuning the dual-responsiveness of thehydrogels. These results also suggest that the CNF–PNIPAAm hydrogels can release drugs on demand.Pubblicazioni consigliate
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