Nanofabrication Using Silk (image) Tufts University Caption At Tufts University School of Engineering, optical-grade silk fibroin aqueous solution, obtained from the cocoons of the Bombyx mori caterpillar, was placed on a substrate and spin-coated to form a silk film. Both positive and negative resists were formed and developed using water. Credit Tufts University Usage Restrictions For education and news use only with proper credit and caption 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.