Functionalized multiwalled carbon nanotubes as ultrasound contrast agents

Lucia Gemma Delogu, Gianpaolo Vidili, Enrica Venturelli, Cécilia Ménard-Moyon, Maria Antonietta Zoroddu, Giovannantonio Pilo, Paola Nicolussi, Ciriaco Ligios, Davide Bedognetti, Francesco Sgarrella, Roberto Manetti, Alberto Bianco

Research output: Contribution to journalArticlepeer-review


Ultrasonography is a fundamental diagnostic imaging tool in everyday clinical practice. Here, we are unique in describing the use of functionalized multiwalled carbon nanotubes (MWCNTs) as hyperechogenic material, suggesting their potential application as ultrasound contrast agents. Initially, we carried out a thorough investigation to assess the echogenic property of the nanotubes in vitro. We demonstrated their long-lasting ultrasound contrast properties. We also showed that ultrasound signal of functionalized MWCNTs is higher than graphene oxide, pristine MWCNTs, and functionalized single-walled CNTs. Qualitatively, the ultrasound signal of CNTs was equal to that of sulfur hexafluoride (SonoVue), a commercially available contrast agent. Then, we found that MWCNTs were highly echogenic in liver and heart through ex vivo experiments using pig as an animal model. In contrast to the majority of ultrasound contrast agents, we observed in a phantom bladder that the tubes can be visualized within a wide variety of frequencies (i.e., 5.5-10 MHz) and 12.5 MHz using tissue harmonic imaging modality. Finally, we demonstrated in vivo in the pig bladder that MWCNTs can be observed at low frequencies, which are appropriate for abdominal organs. Importantly, we did not report any toxicity of CNTs after 7 d from the injection by animal autopsy, organ histology and immunostaining, blood count, and chemical profile. Our results reveal the enormous potential of CNTs as ultrasound contrast agents, giving support for their future applications as theranostic nanoparticles, combining diagnostic and therapeutic modalities.

Original languageEnglish (US)
Pages (from-to)16612-16617
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number41
StatePublished - Oct 9 2012


  • Biocompatibility
  • Echography
  • Nanobiotechnology
  • Nanomaterials
  • Nanomedicine

ASJC Scopus subject areas

  • General


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