Bone Marrow Cryogel (image) Harvard John A. Paulson School of Engineering and Applied Sciences Share Print E-Mail Caption The bone marrow cryogel three weeks after injection. The outside is covered with a bone shell and the inside of the sponge resembles vascularized bone marrow. Credit Harvard University Usage Restrictions with credit Share Print E-Mail 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.