Members of the department of biomedical engineering at Johns Hopkins University School of Medicine in Baltimore are using the LM10-HS, a nanoparticle tracking analysis system made by !%NanoSight Ltd.%! of Salisbury, UK, to study self-assembled polymer/DNA particles for drug delivery. The laboratory chose the system, which is equipped with an electron-multiplying CCD high-sensitivity camera and a 404-nm laser, for particle sizing analysis. The nanoparticle tracking analysis yields a direct number-averaged distribution of particle size as well as absolute particle concentration.