NTRAIN implant (IMAGE) Northwestern University Caption A close-up of the NTRAIN implant shows its internal cellular factories, which, when activated by light, produce precisely-dosed peptide therapies. The device keeps the cellular factories tightly enclosed, only allowing the therapies to diffuse into the body. Credit Northwestern University 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.