Page 56 - EE Times Europe Magazine | June2020

56 EE|Times EUROPE — Sensors Insert

Microfluidic Technologies Diagnose World’s Return to Normal

patients can be tested per hour.” Lifting the
lockdown, however, requires a massive testing
program “on the order of hundreds of millions
of tests per week.” Supplementing the molec-
ular tests will be serological tests to verify the
presence or absence of SARS-CoV-2 antibod-
ies in blood samples.
A key challenge in the exit plan will be to
identify people who have had an asymptom-
atic or mild form of the virus. In those cases,
molecular tests aren’t needed, said Clerc. “If
the patient has contracted the virus but is
in remission or has fought it, the molecular
test will not be able to detect it. A serological
test will be needed to measure the response
of the patient’s immune system to the virus.”
Those tests are simpler and do not necessarily
require microfluidic technologies.
Complicating matters, it is not yet known
whether immunity to the virus lasts weeks,
months, or years. “It’s too early to tell,” said
Clerc, “but we do know that patients develop
immunity, and if we can detect it through
mass screening of the population, we’ll be
able to ease restrictions.”

PREPARING FOR THE AFTER-CRISIS
The availability of established technologies
has helped companies move faster with
Covid-19 diagnostic testing. Lessons learned
from the 2002 SARS outbreak have guided the
development of Covid-19 identification and
detection solutions. Lessons learned during
the Covid-19 outbreak will result in a call for
more versatile diagnostic solutions to prevent
and manage future epidemics.
Tools that provide accuracy, ease of use,
and automation are essential for health
professionals. The holy grail for diagnostics,
Clerc noted, would be a small box capable of
performing any kind of test in minutes. Such
multimodal platforms could address immu-
noassays, clinical chemistry, cytometry, and
molecular diagnostics with the same instru-
ment, at the point of care.
The choice of materials and manufac- virulence of Covid-19, those battling the Portability and affordability are also
turing methods for microfluidic devices is pandemic are in a race against time, and important. Only one instrument would be
determined by their final applications. The companies have mobilized resources to cut purchased to run hundreds of different tests,
first material used for microfluidics was the time to diagnostic test results from days in parallel or not, on that platform. “Con-
silicon, with chips built using the established to hours to minutes, all while increasing sider a doctor’s office or a pharmacy; there is
processes of the microelectronics industry, throughput. Abbott Laboratories’ ID Now, usually not enough room for several instru-
but silicon was quickly replaced by glass Roche Molecular Systems’ Cobas, and ments,” said Clerc. Extending the subject to
and then polymers. Polymers offer the right Cepheid’s Xpert Xpress are rapid point-of- pandemics affecting developing countries, he
solution because they are cheaper, are robust, care (PoC) molecular assays for Covid-19 added that “it is not convenient to transport
and involve faster fabrication processes. detection. Cepheid’s test has the capacity to multiple machines and install them under a
Polydimethylsiloxane is the most common process multiple samples simultaneously; the tent to perform different types of tests.” Com-
material used for microfluidic devices because Cobas and ID Now platforms can handle only panies such as Qorvo Biotechnologies, Bosch
of its optical transparency, biocompatibility, one sample at a time. Healthcare, Truvian Sciences, and Boehringer
elasticity, and simple manufacturing process “The problem with PoC platforms is that Ingelheim Mobinostics are working on solu-
(soft lithography). the throughput of patient tests is very low,” tions to address those scenarios.
said Clerc. “These platforms can handle Once an automated platform has been
LIFTING THE LOCKDOWN between one and eight samples at a time. developed, the next challenge is designing
The sooner a patient is taken care of, the Even though tests are ultra-fast, [yielding a cost-effective microfluidic cartridge able
better the chances of recovery. Given the results] in 15 to 30 minutes, only a few to run various types of tests on the same

JUNE 2020 | www.eetimes.eu