An X-ray image of unlabeled mesenchymal stem cells in test tubes shows the dramatic difference between those tagged with nanotubes that don’t include bismuth (left) and those that do (right).
As more advanced stem cell therapies continue to be developed for all kinds of conditions, it remains a challenge to monitor what happens over time to the seeded cells. Inserting a radiological contrast agent inside these cells would work, but the substance has to be particularly contrasty to X-rays.
An electron microscope image shows bismuth ions (dark lines) sitting inside carbon nanotubes.
Working towards that, researchers at Rice University managed to insert bits of a bismuth based compound inside of ultra-short carbon nanotubes and the resulting material showed very high contrast under CT imaging when looking at pig bone marrow-derived mesenchymal stem cells (MSCs). The researchers believe the new material will help advance stem cell research and possibly allow for a way to track developing cells right in the patient’s body.
From the study abstract:
The relatively high contrast is achieved with low bismuth loading (2.66% by weight) within the US-tubes and without compromising cell viability. X-ray CT imaging of Bi@US-tubes-labeled MSCs showed a nearly two-fold increase in contrast enhancement when compared to unlabeled MSCs in a 100 kV CT clinical scanner. The CT signal enhancement from the Bi@US-tubes is 500 times greater than polymer-coated Bi2S3 nanoparticles and several-fold that of any clinical iodinated contrast agent (CA) at the same concentration. Our findings suggest that the Bi@US-tubes can be used as a potential new class of X-ray CT agent for stem cell labeling and possibly in vivo tracking.
Study abstract: Bismuth@US-tubes as a potential contrast agent for X-ray imaging applications
Rice University: Bismuth-carrying nanotubes show promise for CT scans
