Dennis Discher, University of Pennsylvania (video) University of Pennsylvania Share Print E-Mail Loading video... Caption Penn's Dennis Discher explains how his lab designed a protein that acts a "passport" for the body's immune system. Nanoparticles equipped with this passport last longer in the bloodstream than equivalent particles without it. Credit Kurtis Sensenig, University of Pennsylvania Usage Restrictions With credit roll intact. 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.