Cardiac Cells on a Hydrogel (IMAGE) University of Colorado at Boulder Caption Cardiac cells -- which happen to be in the shape of a heart -- on a hydrogel. Credit Brian Aguado 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.