Medical Design Briefs - June 2022 - 26

A new microfluidic chip for diagnosing diseases that uses a minimal number of components and can be powered wirelessly by a smartphone. (Credit:
Laboratory of Nanostructures and Biosensing, University of Minnesota)
" It's not an exaggeration that a state-ofthe-art,
microfluidic lab-on-a-chip system
is very labor intensive to put together.
Our thought was, can we just get rid of
the cover material, wires, and pumps altogether
and make it simple? "
n Diagnostic Microchip with Liquid
Droplets on the Surface
Many lab-on-a-chip technologies work
by moving liquid droplets across a microchip
to detect the virus pathogens or
bacteria inside the sample. The University
of Minnesota researchers' solution was
inspired by a peculiar real-world phenomenon
with which wine drinkers will
be familiar - the " legs, " or long droplets
that form inside a wine bottle due to surface
tension caused by the evaporation
of alcohol.
Using a technique pioneered by Oh's
lab in the early 2010s, the researchers
placed tiny electrodes very close together
on a 2 × 2 cm chip, which generate
strong electric fields that pull droplets
across the chip and create a similar " leg "
of liquid to detect the molecules within.
Because the electrodes are placed so
closely together (with only 10 nm of
space between), the resulting electric
field is so strong that the chip only needs
less than a volt of electricity to function.
This incredibly low voltage required allowed
the researchers to activate the diagnostic
chip using near-field communication
signals from a smartphone, the
same technology used for contactless
payment in stores.
This is the first time researchers have
been able to use a smartphone to wirelessly
activate narrow channels without
microfluidic structures, paving the way
26
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MDB Tech Briefs 0622_1.indd 26
for cheaper, more accessible at-home
diagnostic devices.
" This is a very exciting, new concept, "
says Christopher Ertsgaard, lead
author of the study and a recent CSE
alumnus (ECE PhD '20). " During this
pandemic, I think everyone has realized
the importance of at-home, rapid,
point-of-care
diagnostics. And there
are technologies available, but we need
faster and more sensitive techniques.
With scaling and high-density manufacturing,
we can bring these sophisticated
technologies to at-home diagnostics
at a more affordable cost. "
Oh's lab is working with Minnesota
startup company GRIP Molecular Technologies,
which manufactures at-home
diagnostic devices, to commercialize the
microchip platform. The chip is designed
to have broad applications for
detecting viruses, pathogens, bacteria, and
other biomarkers in liquid samples.
" To be commercially successful, in-home
diagnostics must be low cost and easy to
use, " says Bruce Batten, founder and president
of GRIP Molecular Technologies.
" Low voltage fluid movement, such as what
Professor Oh's team has achieved, enables
us to meet both of those requirements.
GRIP has had the good fortune to collaborate
with the University of Minnesota on
the development of our technology platform.
Linking basic and translational research
is crucial to developing a pipeline of
innovative, transformational products. "
In addition to Oh and Ertsgaard, the research
team included University of Minnesota
department of electrical and computer
engineering alumni Daniel Klemme
(PhD '19) and Daehan Yoo (PhD '16) and
PhD student Peter Christenson.
www.medicaldesignbriefs.com
ToC
5/25/22 2:50 PM
I cm
The U of M team's microfluidic device functions without
all of the bulky components typically required for
complex lab-on-a-chip diagnostic technology. (Credit:
Laboratory of Nanostructures and Biosensing, University
of Minnesota)
This research was supported by the National
Science Foundation (NSF). Oh received
support from the Sanford P. Bordeau
Endowed Chair at the University of
Minnesota and the McKnight University
Professorship. Device fabrication was performed
in the Minnesota Nano Center at
the University of Minnesota, which is supported
by NSF through the National Nanotechnology
Coordinated Infrastructure
(NNCI).
The University of Minnesota Twin Cities
researchers' paper is published in
Nature Communications. Read the full
paper entitled, " Open-channel microfluidics
via resonant wireless power
transfer, " on the journal's website. Researchers
are also working to commercialize
the technology.
For more information, visit https://cse.
umn.edu.
Medical Design Briefs, June 2022

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Medical Design Briefs - June 2022

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