Researchers use ‘quantum dots’ to screen for diseases

By Joseph Caffarini

Researchers at the University are working to make your next doctor visit much more colorful. They are adapting quantum dot nanoparticles, which are tiny fluorescent crystals, to screen for diseases from heart disease to cancer with the hopes of literally highlighting such ailments for diagnosis.

According to Andrew Smith, cancer biology and nanomaterials researcher and assistant professor of bioengineering, the tiny crystals will primarily be used in optical coherence tomography, where diseases are primarily recognized by sight. An example would be scanning the back of retinas for diabetes, where a light is flashed into the eye to make the quantum dots glow and expose symptoms.

Although quantum dots need a light source to glow, the light does not necessarily need to be from a bulb and could be from radioactive isotopes.

Professor Wawrzyniec Dobrucki, senior research scientist and director of the Molecular Imaging Laboratory at the Beckman Institute, is working on a way to image cardiovascular disease by combining radiotracers and quantum dots. He is fixing quantum dots onto a snowflaked shaped, dendrimer nanoparticle with small amounts of copper-64, then injecting them into mice and rats.

Once in the blood, the tracer sticks to a specific cell receptor usually found in blood vessels with atherosclerosis. Dobrucki intends to use PET scans to locate the radioactive isotopes and determine the general location of the clogged blood vessels. From there, a catheter equipped with a camera is guided to the area so the blockages can be seen glowing, from either light emitted by the camera or from the radiation from the isotopes. Dobrucki’s project is still being developed, but in the future he hopes it will be used in people.

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    There are still many issues that need to be resolved before quantum dots can be commonly used in health care. At the University, labs like Smith’s are focused on making quantum dots safer to use. A few of their concerns are the actual toxicity of the cadmium selenide crystals (quantum dots), and the size of the nanoparticles. The dots need to be made out of a material nontoxic to the body and be small enough to be flushed out of the blood through natural processes. Once these issues are resolved, quantum dots can be used image the human body.