Spherical Nucleic Acid (IMAGE) Northwestern University Caption The most successful spherical nucleic acid (SNA) in the cancer immunotherapy vaccine had the peptide antigen interspersed with DNA. Credit Shuya Wang/Northwestern University 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.