Microdevice (IMAGE) Northwestern University Caption The study's first author, Hossein Zargartalebi, holds the tiny device. The implantable microdevice with the electrode and sensors inside a thin microneedle, the width of just three human hairs. Resembling a continuous glucose monitor, the device sits on the skin outside the body while the microneedle pricks the skin to sample fluids. Credit Northwestern University Usage Restrictions add credit License Original 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.