[♪ INTRO]
Though they’re perhaps not as glamorous as medicines or vaccines,
diagnostic tests play a central role in pandemic management.
It’s just really hard to do much of anything if you don’t know who
actually has the germ in question.
And for COVID-19 specifically, researchers pulled out all the stops to design accurate tests.
These tests have some drawbacks, though. Like,
they require experienced personnel, and the results aren’t exactly instant.
So what if I told you that in the future, we could be diagnosing infections like COVID-19
in five minutes or less with a test people could give themselves?
That’s the hope of new research recently published in the journal ACS Nano.
In a proof-of-concept paper, researchers detailed a different kind of test
that can produce reliable COVID results in under five minutes!
Step one of any COVID test is to get a sample from the patient.
This often involves one of those long nasal swabs to grab some fluids or a vial of blood.
After that, there are a couple main options — each with downsides.
One approach is to test for antibodies. These are Y-shaped immune proteins that
are specific to a particular germ, so they can help stop infections in a targeted way.
And since they’re specific, they can also tell doctors what germs have recently attacked.
The major downside here is that it can take days or even
weeks for the body to start producing enough antibodies to be detected,
so if the infection is still in the early stages, this kind of test is unreliable.
Also, antibody testing requires blood samples, which must be collected by trained personnel.
That’s why many of the most commonly used tests screen samples for the genetic code of the virus
lurking in bodily fluids.
Like all coronaviruses, SARS-CoV-2 is an RNA virus, so these tests look for viral RNA.
But RNA molecules are too small to just
see, and it’s not like a person’s bodily fluids are packed with them.
So generally, to accurately detect an infection,
you first have to make lots of copies of the viral RNA.
And that process can take a while. Plus, it tends to require specialized equipment,
chemicals, and personnel.
To solve these limitations, the research team behind the new paper turned to nanotechnology.
Rather than relying on amplifying what’s in the sample,
they designed a small biosensor chip that can detect tiny amounts of SARS-CoV-2 RNA.
The sensor consists of filter paper coated with graphene:
a honeycomb-like lattice of carbon atoms that is super-thin and very conductive.
On top of this graphene layer are gold nanoparticles, which are also very conductive.
And attached to these gold nanoparticles are specially-designed strands of DNA.
These snippets of DNA act as probes by specifically binding to parts of
the virus’s RNA genome — specifically, chunks of a piece called the N-gene,
which codes for one of the virus’s important structural proteins.
In fact, the chip actually uses
multiple DNA detector strands to target two different sections of this gene.
This means that even if the virus in the sample has a mutation on one part,
it can still be detected.
Anyhow, the binding of the viral RNA to these DNA probes
creates a change in the electrical charge of the molecules.
And since gold and graphene are both highly conductive,
the electrical signal travels across the paper to a circuit
to deliver it to a computer, which then spits out the positive result.
The team tested these sensor chips on 48 clinical samples,
about half of which were known to be infected based on standard tests.
Not only did the chip correctly distinguish between the infected and non-infected samples,
on average, the results were delivered in under five minutes.
That kind of fast turnaround is awesome for so many reasons! Like,
infected patients can start treatment sooner, and negative patients aren’t waiting and worrying.
And the researchers claim the test is just as,
if not more sensitive than the ones currently being used.
Plus, it could spot different amounts of the virus—what experts call the
viral load—which is super useful for understanding infection dynamics.
But what’s really exciting here is that this kind of test
could change how we spot infections in general.
For one thing, the materials needed are relatively inexpensive.
The researchers suggest chips like this could be sold for about $10 each.
They’re also super portable and can be integrated with all kinds of computers,
including smartphones, so they could be used in a doctor’s office or at home.
And in theory, scientists could design similar rapid-testing chips for any virus — new or old!
So not only could this be a new way of detecting COVID-19,
it could lead to more rapid and accessible tests for all sorts of diseases,
which would be a boon for patients, doctors, and researchers alike.
Though, first, these sensors are going to have to prove themselves to oversight agencies like the
US FDA, which probably means in-depth testing and comparison to other tests on the market.
And someone will have to figure out how to mass produce the chips,
as well as the hardware and software needed to actually run the test.
So I wouldn’t expect these tests to be everywhere, like, tomorrow.
Still, it’s pretty cool to see technologies like this coming into their own — and I
wouldn’t be surprised if nanobiosensors soon become all the rage in medicine.
Thanks for watching this episode of SciShow News! And a special thank
you to Matthew Brant, our President of Space!
We here at SciShow salute you Matthew! And
we’re truly grateful to have you as a part of our awesome patron community.
If you want to learn more about joining that community — including how you, too,
could be President of Space — you can head on over to Patreon.com/SciShow.
[♪ OUTRO]