In the ongoing global efforts to contain the Covid-19 virus, the ability to conduct rapid mass testing is proving critical to success. It is also an area where many countries are facing major challenges. Researchers at Carnegie Mellon University and the University of Pittsburgh have just developed a test that may help overcome this challenge.
Created by a joint
team of engineers and virologists, the test enables Covid antibodies, the
blood-borne protein that attacks the coronavirus, to be detected in 10 seconds.
The presence of these antibodies in a person’s blood indicates that they were
previously infected by the virus. Pinpointing who within a population has Covid
antibodies helps track the virus’ progress, including by identifying who may
have developed immunity.
Micro 3D printing
technology lies at the heart of this research innovation. Dr. Rahul Panat,
Associate Professor of Mechanical Engineering at Carnegie Mellon University,
whose group developed the test, explained:
“Micro 3D printing
allows you to produce new shapes in devices and new combinations of materials.
The progress we are making today in biomedical devices is inherently tied to
the progress in microfabrication.”
The device is made
using trademarked Aerosol Jet 3D electronics printers developed and patented by
Optomec, a U.S.-based company specializing in additive manufacturing
technology. About the size of a U.S. quarter coin, the device is formed by
printing gold micropillars onto a substrate, coating them with reduced graphene
oxide, then attaching Covid antigens, the markers of the virus. A pinprick of
blood is obtained from the person being tested, and if the sample has any Covid
antibodies they latch on to the antigen, creating an electrochemical reaction.
Unlike other
manufacturing processes that create a smooth surface finish, the Optomec
aerosol jet printer produces a rough surface on the gold micropillars. This
trademark ‘stickiness’ allows the antigen to easily load onto the micropillar
resulting in it being able to detect even very small amounts of antibodies. A
single device costs in the range of tens of dollars to make.
Like a Home Glucose
Test
The device gets
connected to a dongle that has a small electrochemical analyzer, which confirms
the presence of antibodies. The dongle connects to a smartphone that reads the
result on a custom app. Both interfaces—the dongle and smartphone app—are
already widely available on the market. One advantage of choosing such
interfaces, according to Dr. Panat, is that:
“It lowers the
technical expertise needed to take a reading. It can be like a glucose test you
do at home.”
After a test is
performed, the device gets washed with formic acid and another test can be done
in a minute. While at least 10 tests can be done with complete accuracy, the
detection capability weakens after that and the device needs to be replaced.
The research team published its preliminary data in September, with
larger-scale trials underway at the University of Pittsburgh Medical Center.
With parts of the
world getting battered by a new wave of Covid infections and a vaccine very
likely still months away, testing is set to remain an indispensable part of
nations’ Covid mitigation strategies. For example, when China, which had been
doing very well at containing Covid-19 over the summer, experienced an outbreak
in October in the eastern city of Qingdao, it managed to stave off a resurgence
by testing all of Qingdao’s 10 million residents in a few days. Dr. Panat said:
“Rapid mass testing
can help us eradicate the virus by effectively isolating patients. If a test
takes 24 or 48 hours to get results—or even 20 minutes—that is simply too
long.”