Biocompatible Hydrogel from a Green Tide-Forming Chlorophyta

Abstract

The green-tide chlorophyta Ulva contains the functional acidic polysaccharide ulvan in its cell wall. Here, we focused on the development of a novel soft material that can be used as a biocompatible ion exchanger. Combining chitosan and ulvan solutions was found to yield a hydrogel with various functions. This ulvan-chitosan polyion complex gel was more stable than an alginic acid-chitosan gel under both acidic and basic conditions. However, an ulvan-chitosan gel-coated vessel showed only a mild effect of preventing blood clotting, whereas a heparin-chitosan gel-coated vessel prolonged clotting time. In terms of the ion-exchange behavior, the ratio of the CuSO4-concentration in a CuSO4 solution treated with the gel to that in a solution without the gel showed that increasing the initial CuSO4 concentration increased CuSO4 adsorption in the gel. These studies show that this novel hydrogel can be used as an ion exchanger as well as in other applications.