Single-walled carbon nanotubes (CNTs) are promising candidates for near-infrared (NIR) fluorescent labels in diagnostic fields. We here report a complex of oxygen-doped CNT (o-CNT) and streptavidin (SA) to prepare CNT-based NIR labels with a high reaction efficiency in immunoassays [1]. This complex specifically binds to biotin molecules by conjugating a linker molecule of phospholipid polyethylene glycol (PL-PEG) to SA (o-CNT-SA). The immunoprecipitation (IP) reaction efficiency between o-CNT-SA and biotin reaches 79.3% by uniformly covering the surface of o-CNTs with SA conjugated PL-PEG (SA-PEG). Further, we also report the biodistribution and toxicity of oxidized super-growth single-wall carbon nanotubes (oxSG) injected intravenously into mice over 3months [2].

[1] K. Kojima, Y. Iizumi, M. Zhang, T. Okazaki, submitted.

[2] M. Zhang, Y. Xu, M. Yang, M. Yudasaka, T. Okazaki, 15, 798-811 (2021).