Layered Look (IMAGE) DOE/Pacific Northwest National Laboratory Caption Electron-microscopic images show enzyme-coated carbon nanotubes of varying thicknesses. The sensitivity of a biosensor increases with thickness, to about six layers (right). Credit DOE/Pacific Northwest National Laboratory 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.