Development of Iron-Containing Multiwalled Carbon Nanotubes for MR-Guided Laser-Induced Thermotherapy

Abstract

Aims: To test iron-containing multiwalled carbon nanotubes (MWCNTs) as bifunctional nanomaterials for imaging and thermal ablation of tumors. Materials & Methods: MWCNTs entrapping iron were synthesized by chemical vapor deposition. The T2-weighted contrast enhancement properties of MWCNTs containing increasing amounts of iron were determined in vitro. Suspensions of these particles were injected into tumor-bearing mice and tracked longitudinally over 7 days by MRI. Heat-generating abilities of these nanomaterials following exposure to near infrared (NIR) laser irradiation was determined in vitro and in vivo. Results: The magnetic resonance contrast properties of carbon nanotubes were directly related to their iron content. Iron-containing nanotubes were functional T2-weighted contrast agents in vitro and could be imaged in vivo long-term following injection. Iron content of nanotubes did not affect their ability to generate thermoablative temperatures following exposure to NIR and significant tumor regression was observed in mice treated with MWCNTs and NIR laser irradiation. Conclusion: These data demonstrate that iron-containing MWCNTs are functional T2-weighted contrast agents and efficient mediators of tumor-specific thermal ablation in vivo.

Keywords::

• cancer
• contrast agent
• in vivo
• laser
• MRI
• nanotube
• T2
• thermal therapy

Financial & competing interests disclosure

This work was supported in part by National Institutes of Health Grant RO1CA12842 (SVT). Ravi Singh was supported, in part, by training grant T32CA079448. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Ethical conduct of research

The authors state that they have obtained appropriate institutional review board approval or have followed the principles outlined in the Declaration of Helsinki for all human or animal experimental investigations. In addition, for investigations involving human subjects, informed consent has been obtained from the participants involved.

Acknowledgements

We thank the Center for Biomolecular Imaging at Wake Forest University School of Medicine (NC, USA) for assistance with the 7T Bruker micro-MRI scanner and the Microscopy Core of the Comprehensive Cancer Center for the transmission electron microscope and light microscope.

Additional information

Funding

This work was supported in part by National Institutes of Health Grant RO1CA12842 (SVT). Ravi Singh was supported, in part, by training grant T32CA079448. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.