Nanoshells (image) University of California - San Diego Caption The enzymes are loaded into the nanoparticle very efficiently through pores on its surface and later encapsulated with a shell of nanoporous silica. The shell's pores are too small for the enzyme to escape but big enough for diffusion of amino acids that feed cancer cells in and out of the particle. The enzymes remain trapped inside where they deplete any amino acids that enter. Credit Inanc Ortac Usage Restrictions with credit 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.