Smart Sponge to Control Drug Delivery (IMAGE) North Carolina State University Caption The sponge-like matrix of chitosan surrounds a reservoir of insulin or other drugs. Credit Zhen Gu Usage Restrictions Image credit must be given. 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.