Hydrogel of β-cyclodextrin-Grafted Polyethyleneimine: pH-Sensitive Release

초록

Novel pH-sensitive hydrogels were prepared by grafting beta-cyclodextrin (beta CD) to polyethyleneimine (PEI) and cross-linking beta CD using epichlorohydrin (EPI). While the molar ratio of beta CD to PEI was kept to 1:50, the molar ratio of EPI to beta CD was varied so that it was 3/1, 5/1, and 10/1. When the EPI to beta CD ratio was higher, the degree of equilirium swelling and the percentage release were lower, possibly due to a higher cross-linking density. The % release of blue dextran was much less than that of fluorescein isothiocyanate-dextran (FITC-dextran). The electrostatic interaction of blue dextran with the hydrogel is believed to suppress the release of the dye. Among the hydrogels prepared in this work, the hydrogel prepared using the beta CD to EPI ratio of 1/5 was the most pH sensitive in terms of the degree of swelling and the degree of FITC-dextran release.

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