Biodefunctionalization of functionalized single-walled carbon nanotubes in mice.

Chemically modified carbon nanotubes with hydrophilic functionalities such as polyethylene glycols (PEGs) are widely pursued for potential biological and biomedical applications. In this study, PEGylated single-walled carbon nanotubes (PEG-SWNT) were intravenously administrated into mice to study their biodefunctionalization in vivo by using complementary Raman and photoluminescence measurements. There was meaningful defunctionalization of PEG-SWNT in liver over time, but not in spleen under similar conditions. The evidence from spectroscopic characterization and analyses is presented, and mechanistic implications are discussed.