This was consistent with a persistent surface charge, matched ferritin–polymer nanostructure, comprising on average eleven electrostatically coupled polymer chains per cationized sub-unit and a theoretical polymer content of 34 wt% [34% by weight]. Please be careful when working with nanoparticles. Safe work practices, including the use of personal protective equipment (PPE) and clothing are still being assessed. Here are 3 links that may provide some information: http://multimedia.3m.com/mws/mediawebserver?mwsId=66666UuZjcFSLXTtMxMalxM2EVuQEcuZgVs6EVs6E666666-- http://pubs.acs.org/cen/coverstory/84/8418nanotechnology2.html http://www.nanolawreport.com/2008/02/articles/nanoparticle-penetration-of-respirators-clothing-and-gloves/