Polished and Etched Mouse Incisor Enamel (IMAGE) Northwestern University Caption Left: Smooth polished mouse enamel. Right: After an acid bath, the grain boundaries dissolved quickly, leaving the crystals that make up the nanowires behind. Credit Credit: Northwestern University Usage Restrictions Credit must accompany use of image 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.