Swelling and Metal-Ion Adsorption Properties of Dopamine-Conjugated Polyaspartate Hydrogel

摘要

Biodegradable hydrogels based on dopamine-modified polyaspartate were prepared, and the swelling behavior was investigated along with their metal-ion adsorption property. The catechol group of dopamine is well known to exhibit unique adhesive characteristics on a variety of organic/inorganic surfaces. Dopamine-modified polysuccinimide (DOP-PSI) was prepared by nucleophilic reaction of dopamine to polysuccinimide, and then crosslinked by adding diaminobutane as the crosslinker to yield an organogel in DMSO. Subsequently, the DOP-PSI gel was hydrolyzed in a pH9 buffer solution to produce the final, water-swollen hydrogel of DOP-modified polyaspartate (DOP-PASP). The swelling property of DOP-PASP was investigated in various aqueous solutions containing different metal-ions. The swelling degrees of the resulting gels were variable depending on the preparation conditions, such as polymer concentration and crosslinker level, though greater swelling of 450 g/g was observed in water. In ion-containing solutions, the swelling decreased as the ion concentration increased. As the valency of the ion increased, (i.e., Na+1 < Ca+2 < Fe+3) the swelling decreased abruptly due to the different ion-binding abilities of carboxylate and catechol groups with metal-ions. Adsorption of Fe+3 ions in aqueous solution was examined to show a high adsorption capacity of 270 mg/g-gel approximately. The results suggest that DOP-PASP has the potential for use as a hydrogel adhesive and metal-ion absorbing material.