Before and after: a hydrogel (IMAGE) KTH, Royal Institute of Technology Caption A hydrogel before and after adsorption of methylene blue in an aqueous solution. Credit Giuseppe Melilli Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.