| 초록 |
Stimuli-sensitive polymer hydrogels, especially those of the thermo-reversible kind, have attracted considerable attention for their potential use in biomedical applications, because of the reversible sol-gel transition which they undergo upon heating or cooling. Herein, we report on injectable biodegradable block copolymer hydrogels which exhibit a sol-gel transition caused by pH change, as well as by temperature change. They show a sensitive, reversible sol-gel transition with a small pH range (pH 8.0 - 7.4) and a temperature change in the region of room temperature to the body temperature. These pH and temperature sensitive hydrogels were prepared by adding pH sensitive moiety (sulfonamide group) to the temperature sensitive block copolymer. This can be made by the very precise molecular weight control of block copolymer and the prudential tuning of hydrophilic-hydrophobic balance. When you inject these polymer solutions (pH 8.0) at room temperature, it forms a gel inside the body in a short time (at pH 7.4 and 37 ℃). These hydrogels maintain the gel state in buffer solution (pH 7.4, 37 ℃) for a long time (more than 2 weeks), and the pH of the gel does not changed by the degradation of the aliphatic polyester block. It is expected that these hydrogels will be able to be used as a carrier for hydrophobic drugs, proteins and cells, etc. Moreover, they can also be employed as a injectable carrier, using a long guide catheter into the body because they do not change into the gel form only by increasing temperature. |
