COLL 497 |
| Poly(N-isopropylacrylamide) hydrogels undergo a thermoresponsive phase transition during which the hydrogel deswells, expelling water and solutes. The phase transition temperature is modulated by varying the ratio of the cross-linkers N,N'-methylenebisacrylamide (MBAm) to N,N'-cystaminebisacrylamide (CBAm) coupled with in situ synthesis of gold nanostructures. Following synthesis, the hydrogels are loaded with one of five macromolecules. The temperature-dependent release profile of these molecules from the hydrogel is investigated using fluorescence and UV-Vis spectroscopy. The effect of size and charge of macromolecules, changing amounts of crosslinking agent, and presence of Au nanostructures is studied. The hydrogels release most of the macromolecule at 25 °C. At 40 °C, the release from most hydrogel samples decreases drastically as they undergo a phase transition and shrink, closing the pores on their surface. However, CBAm cross-linked hydrogels containing gold nanostructures continue to release the drug at 40 °C because of their higher phase-transition temperature. |
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Polymer-Nanoparticle Systems: Theory, Simulation, Experiments
2:00 PM-5:00 PM, Thursday, April 10, 2008 Morial Convention Center -- Rm. 227, Oral
Division of Colloid & Surface Chemistry |