Using Quantum Dots To Detect The Early Signs Of Cancer

Illustration for article titled Using Quantum Dots To Detect The Early Signs Of Cancer

For a long time, cancer screening has been difficult and invasive. Doctors had to use invasive surgical procedures and unreliable tests. Now, scientists have harvested the power of quantum semiconductors to test for very early signs of cancer.


The test, as reported in the August issue of the journal Genome Research, relies on observing DNA methylation. The process involves two substances: methyl (an organic chemical group) and cytosine (the C in GATTACA). During DNA methylation, the loose methyl groups attach to the cytosine in DNA, which can lead to the suppression of important tumor-fighting proteins, and maybe eventually to cancer.

To detect this nefarious change in DNA, the newly-developed testing process essentially removes any non-methylated DNA, and dyes and measures whatever is left. This gives the tester an idea of how much methylation is happening in a patient's DNA, which also demonstrates the patient's risk for cancer.

Worth noting is the strange quantum dye that the process uses. The modified methylated DNA strands are mixed with "quantum dots," or tiny semiconductor crystals that can easily transfer energy. When light is shined on the quantum dots, now adorned with DNA strands as in the picture above, the energy is quickly put into the nearby molecules, lighting them up like a Christmas tree and making it easy for doctors to measure them.

From a practical angle, this test, as compared with current cancer screenings, is more sensitive and quicker. It would involve only a simple blood test, as opposed to an invasive biopsy. Plus, this test can specify which cancers a patient is at risk for. It's great to see chemistry nerds making life easier and safer for all of us!

New DNA test uses nanotechnology to find early signs of cancer [via EurekaAlert]

Further Reading: What's the Future of Cancer Diagnosis?


(Image: glowing methylated DNA arrayed around a quantum dot, from Yi Zhang/JHU)



This is actually quite a novel and interesting variation of the usual use of quantum dots.

Quantum dots have since several years been used for cancer detection. Usually they're used as small "repeater lamps" as they can shine very brightly when shone upon with a different wavelength of light. Often the wavelength is affected depending on whether the dot has made contact with a target molecule or not.

The downside is that we get a rather rough measurement, as multiple DNA strands can stick to the quantum dots.

So, good for "yes-no"-answers or simple imaging, but not so good for more sensitive detailed investigations like early tests.

Those researchers have made the dots pass on incoming light to fluorescent markers at the end of the DNA strands straightaway and having these other molecules shine instead, giving a more exact count of the number of DNA strands detected.

Very clever!