Detecting cancer through ultra-low detection of microRNA in blood
SYDNEY, Australia—There are all kinds of “gold standards” in clinical diagnosis and treatment, as well as in testing and screening tools in life sciences, but University of New South Wales Sydney (UNSW) researchers in Australia have “struck gold” in diagnosis with nanotechnology. Specifically, they used gold-plated nanoparticles to grab on to targeted microRNAs (miRNAs) and allow them to be more easily extracted, leading to a new method of detecting ultra-low levels of miRNAs in a blood sample. This is a breakthrough that could make diagnosis of cancer and other illnesses quicker and more efficient, and perhaps enable it earlier in the course of such diseases.
This method is potentially valuable not just because typically a much larger sample needs to be obtained to extract the miRNA amounts seen with this method—for which a finger prick may be all that is required—but also because impaired miRNA activity has been linked with the formation of cancerous tumors as well as metastasis.
In the paper published in Nature Nanotechnology regarding the work, the researchers reported modifying gold-coated magnetic nanoparticles with DNA to match the miRNA they wanted to detect. According to Prof. Justin Gooding, the nanoparticles are, in effect, “dispersible electrodes,” and when circulated through the blood, they capture the miRNA before a magnet is used to recapture the nanoparticles with the newly attached microRNA.
“Now we get more of the microRNA because the dispersible electrodes capture nearly everything in the sample,” Gooding said. “Because the capture is so effective, we get higher sensitivities and can detect much lower limits. And since we bring them back to the electrode under a magnet, our response time is much faster.”
And faster also means less expensively, he noted: “It could be orders of magnitude cheaper. Our method takes 30 minutes compared with almost 12 hours for quantitative polymerase chain reaction.”
Key to the new technology is not just the ability to detect lower concentrations of miRNA but the ability to detect a broad range of concentrations, the researchers pointed out, with Gooding explaining that “This is really important to determine whether the levels of different microRNAs have increased or decreased.”
“We can do this very quickly compared with the gold-standard nucleic acid amplification methods. And we can do it in unprocessed blood.”
Gooding said he would expect the technology to be available within three years, pending regulatory approvals.
This new diagnostic technique follows on the heels of a similar advance made by another UNSW research team—working with the University of Copenhagen—that developed a new way to detect early-stage cancer cells in the blood using a malaria protein. That research was published recently in Nature Communications.
“We have developed a method where we take a blood sample and with great sensitivity and specificity, we’re able to retrieve the individual cancer cells from the blood,” UNSW’s Prof. Chris Heeschen said at the time. Heeschen added, much in the same vein as Gooding and his team, that “We catch the cancer cells in greater numbers than existing methods, which offers the opportunity to detect cancer earlier and thus improve outcome for patients.”
Heeschen said the hope is that this new method, in which malaria protein VAR2CSA sticks to cancer cells, can be used as a more effective way to screen for cancer in the near future. Similarly to Gooding, he predicts only a couple years or so to market if a diagnostic R&D company were to take on development work around the method.
Reportedly, the method based on the malaria protein does not discriminate between cancer types and can detect all carcinoma cancers, accounting for 95 percent of cancers detected in humans.
The researchers envision being able to use the method to screen people at high risk of developing cancer in the future. However, they also expect that this method can be used as a biomarker indicating whether a patient with mostly vague symptoms indeed has cancer or not. This may also enable doctors to determine the stage of the disease.