Carbon nanomaterials (CNMs) are used in the development of various functional materials and products as well as in basic research, mainly in the engineering field. Owing to their high biocompatibility, application of CNMs to biomaterials is widely expected. Many researchers have examined the kinetics and toxicity of intravenously administered CNMs. However, little research on the in vivo kinetics of locally implanted CNMs has been reported. In this study, single-walled carbon nanotubes (SWNTs) were implanted between the periosteum and parietal bone of mice. The in vivo kinetics of the implanted SWNTs were observed by near-infrared (NIR) fluorescence imaging (excitation, 730 nm; emission, &gt;1000 nm). The body is highly transparent to light in the NIR region and autofluorescence in this region is low, making NIR fluorescence suitable for bioimaging. SWNTs were visible in the subcutaneous tissue and medullary cavity. Fluorescence was observed in the cranial region, and its intensity gradually decreased over 24 hours. Fluorescence was not observed in other organs, including the liver, spleen, and lung, by whole-body imaging. After 56 days, fluorescence was weakly, but clearly, observed at the implanted area. The fluorescence weakened over time, possibly because SWNTs became bundled or adsorbed fluorescence-quenching materials in the tissue. These findings suggest that locally implanted SWNTs remain at the site of implantation and do not migrate in detectable quantities to other organs. We expect that this proof-of-concept for the biodistribution of SWNTs after local implantation will promote future studies for application of CNMs to biomaterials.

Near-infrared photoluminescent imaging of carbon nanotubes locally implanted in mice

256th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.