Dipanjan Pan, PhD, Professor in Diagnostic Radiology and Nuclear Medicine and Pediatrics at UMB, Professor of Chemical, Biochemical and Environmental Engineering at UMBC, talks about a new COVID test that uses gold nanoparticles to quickly and easily identify if the virus is present.
Can you tell me what you and your colleagues have been doing in regard to the COVID testing?
DIPAN JAN PAN: During the last few months, there have been a lot of strides in terms of the early detection of the COVID-19 virus. Most of these tests that are FDA approved, are mostly antibody-based serological tests. The patient would give their blood, and the test would determine if there is an antibody present in that person’s body which is being generated because of the virus infection. The problem is, after a person gets infected with the virus, it takes about seven to 10 days for our body to produce the antibody. So, most of the times these tests are not accurate. It cannot detect the virus at a very early stage. There is a huge clinical need to detect the virus as early as possible. With that motivation, what we tried to do is come up with a test that is based on the RNA of the virus. You can do that from the patient’s saliva or nasal swab as early as the first day of the infection. Now, is there any other test out there that works the same way? Yes. There are tests out there. In the hospitals, they use a technique called RT-PCR. It also works similarly to collect RNA and then looks for the signal from that RNA. However, in cases like COVID-19, which is a global pandemic, you need a solution which is more simple, straightforward, inexpensive and where you’re not really relying on expensive instrumentation or skilled personnel to run those tests which is only possible at a hospital setting or large diagnostic centers. So here, what we’re trying to develop is something that is simple and can produce results at a point-of-care with higher accuracy and speed.
Tell me about the materials you’re using. Why do they work so well in this kind of setting?
DIPAN JAN PAN: We’re using nanoparticles made out of metal gold having nano-metric length, like one billionth of a meter. These are tiny particles made from solid gold which has a property called plasmon resonance. So, in a simpler form, we can say the gold absorbs light and gives off light in such a way that it becomes visible by the naked eye. When gold particles change their size, it changes color. So, based on that, our human eye, or naked eye, can appreciate, or detect, the change in color. When we use the gold particles that are decorated with some molecules that are highly specific for COVID-19 virus RNA, they tend to aggregate, or come close to each other. This change can immediately be detected by the naked eye, and that’s the key to our success. Then, we add another reagent so that some good biochemical reaction happens. The whole thing precipitates out and you can literally see that there are sediments at the bottom of the test. That’s a visual confirmation that the virus is present, or the virus is not present.
Why is it so important that the test be quick and able to be detected by the naked eye and no need for lab equipment?
DIPAN JAN PAN: That is a great question. Most of the techniques that are out there require something called RNA amplification. That means the amount of the virus is so tiny that in order to detect it, you need to magnify it synthetically. Here in this case, we don’t need it because there is a ‘plenty of room at the bottom’. This is a quote from a famous physicist, Richard Feynman, who said there is plenty of room at the bottom – which basically means when you are moving down the scale from millimeter to centimeter to micrometer and then nanometer, the surface to volume area of that material increases. That means we can put a whole lot of thing on the surface of these particles. That is called multi-valancy. So, we are exploiting this multi-valancy property of the gold particles to artificially amplify the response of the virus.
How close are you to approval? And, what is the next step to get this test commercially available?
DIPAN JAN PAN: Usually, the process is a lot longer because we need to do a lot of clinical studies, run clinical samples and then submit to the FDA, which takes time to give us approval. But, under this unique circumstance of a global pandemic, the FDA is offering something called a pre-authorization use. We are analyzing clinical samples to validate our results and so far, our results have been satisfactory as expected. My goal is to get more resources in for research in terms of finding that will continue to help develop it. Simplicity of our test makes it unique and we anticipate a quick turnaround in terms of the FDA approval.
Interview conducted by Ivanhoe Broadcast News.
END OF INTERVIEW
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If you would like more information, please contact:
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University of Maryland School of Medicine
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