Functionalized multiwalled carbon nanotubes as ultrasound contrast agents

Abstract

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.

Properties of ultrathin cholesterol and phospholipid layers surrounding silicon-carbide nanotube: MD simulations

“…In the past decade the increasing numbers of attempts to use the carbon nanotube (CNT) or graphene in medicine is observed. This is because CNTs exhibit physical properties (strong optical absorption in the near-infrared [6], photoluminescence [7], Raman scattering [8], photoacoustic [9] and echogenic properties [10]) which can be used to track and visualize CNTs in a biological milieu [11][12][13][14][15][16][17]. In this context we simulated the influence of graphene wall on the dynamics of a cholesterol cluster placed over a transmembrane protein [18].…”

In vitro methods to study bubble-cell interactions: Fundamentals and therapeutic applications

“…Other systems have also been reported in the literature such as the hydrolyzing, gas-generating nanoparticles by Kang et al, 137 able to create bubbles over timescales of several minutes, or carbon nanotubes as ultrasound contrast agents. 138 Describing all of these systems, however, would be beyond the scope of this review.…”

Direct visualization of carbon nanotube degradation in primary cells by photothermal imaging

“…30 This type of nanotubes has been extensively used for different applications including therapy and imaging. [32][33][34] In particular, they have been explored as carriers of small interference RNA for gene silencing. 32,33 1 Their biodistribution and biodegradation have been also thoroughly assessed.…”