Introduction:   Hydrogels have been extensively studied as controlled drug delivery carriers for bioactive molecules because of their bio-compatibility, high water content, and rubbery consistency. Recently, smart hydrogels that respond dramatically to external stimuli such as changes in temperature, pH, light or solvent composition have been of both fundamental and commercial interest. In this study, photo-responsive hydrogel was developed by isopropylacrylamide(IPAAm)-based polymeric materials. The hydrogel comprised photo-acid generator, o-nitrobenzaldehyde(NBA) and pH-sensitive polymer, that was IPAAm-co-2-carboxyisopropylacrylamide (CIPAAm).Experimentals:  The hydrogel was put in water and UV light was irradiated to the hydrogel with keeping the fixed intensity and distance. The sized was also measured described above. To explore the drug releasing, freeze- dried cylindrical gels with 2 mm in diameter were swollen in FITC-dextran containing NBA for 2 days. Afterwards, the FITC-dextran loaded gels were exposed to UV light for 10 min to trigger the drug release.Result and Diccussion:  NBA integrated gels could drive local acid generation upon UV irradiation by uniformly released protons inside the hydrogel followed by shrinking of the gels without forming polymer skin layer at the gel surface. To demonstrate the photo-triggered drug releasing process, FITC-dextran, that is model drug, loaded gels were irradiated to alternatively turning on and off of the UV light. Dextran slowly released from the hydrogels prior the first UV exposure. The release of dextran increased obviously to almost 60% after 10 min UV irradiation. After UV light was turned off, the gels began to gradually swell and drug release became very slow. After a second UV illumination, the drug release again increased. The rate of drug release at 37C was slower than 20 degree C incubation, because the collapsed polymer network might retard the release of dextran.

Smart hydogel using pH-jump reaction with PAG for biomedical application

248th National Meeting (2014)

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