János FENT and Susan LAKATOS
Research Institute, Military Hospital, Budapest, HUNGARY
Recently various engineered nanoparticles are popular candidates for implementing them into diagnostics, therapeutics or using them for drug delivery. In some extent all these procedures involve direct contact between the nanoparticles and the blood constituents. Most of the nanoparticles are more or less toxic or have prothrombotic effects. A great deal of efforts has been made to decrease these unfavorable effects, mainly by attaching various functional groups to the surface of the nanoparticles. The main goal of our study was to compare single-wall carbon nanotubes (SWNT) with their functionalized counterparts bearing –NH2, -OH, -COOH groups or polyethylene glycol (PEG) in terms of their effect exerting on platelets. All these SWNTs, but NH2-SWNT induce in vitro activation of human blood platelets and platelet aggregation, although at different extent, as judged by flow cytometry and aggregometry. Although attaching PEG to various nanoparticles seems to be widely accepted as a mean to increase biocompatibility, according to our experience PEG-SWNT has the strongest platelet activation power. Our results indicate that there is no “universally good” functional group; each kind of functionalized nanoparticle needs to be tested individually.