A better image

Rice University doctoral student Balaji Sitharaman has created a new class of contrast agent that could, for the first time, allow magnetic resonance imaging of individual cells.

More than 25 million patients in the US undergo MRIs annually, and doctors use contrast agents in almost of quarter of those procedures. Contrast agents increase the sensitivity of the scans, making it easier for doctors to deliver a diagnosis. The most effective and commonly used contrast agent is the toxic metal gadolinium.

Sitharaman has created new forms of contrast agents by encasing gadolinium inside fullerenes. Fullerenes are single molecules of carbon atoms arranged in spherical or tube-shaped structures.

By enclosing the gadolinium inside the carbon molecules, Sitharaman has simultaneously reduced the toxicity of the metal to near zero while boosting its effectiveness as a contrast agent.

More recently, he has discovered a method of encasing as many as 100 atoms of the metal inside a short length of carbon nanotube. The resulting 'gadonanotubes' are 100 times more effective as contrast agents than the best forms in clinical use.

In future work, Sitharaman plans to use existing methods of attaching antibodies and peptides to fullerenes to try to create a contrast agent that will bind only with diseased cells such as cancer cells.

He is hopeful that these tissue-specific imaging agents might allow for the first intracellular, individual cell MRIs.