Macrophages (Red) with Active Substances (Green) (image) Martin-Luther-Universität Halle-Wittenberg Share Print E-Mail Caption Images of macrophages (red) in which the active substance (green) is distributed. On the left, the active substance heparin is shown, on the right hyaluronic acid. Credit Hala Al Khoury / Uni Halle Usage Restrictions Use 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.