Tech Briefs Magazine - August 2021 - 49

EGaIn provided both metal-like electrical
conductivity and stretchability. The
entire device was embedded in a stretchable
silicone elastomer.
The upgraded device employed the
same architecture but significantly im -
proved the thermal engineering of the
previous version, while increasing the
density of the semiconductor elements
responsible for converting heat into
electricity. One of the improvements
was a high-thermal-conductivity silicone
elastomer - essentially a type of rubber
- that encapsulated the EGaIn interconnects.
The
newest iteration adds aerogel flakes
to the silicone elastomer to re duce the
elastomer's thermal conductivity. Exper -
imental results showed that this innovation
reduced the heat leakage through
the elastomer by half. The aerogel stops
the heat from leaking between the device's
thermoelectric " legs. " The higher the heat
leakage, the lower the temperature that
develops across the device, which translates
to lower output power.
The latest iteration of the flexible
device performs an order of magnitude
better than the original device. The technology
employs the same semiconductor
elements used in rigid devices perfected
after decades of research. The approach
also provides a low-cost opportunity to
existing rigid thermoelectric module
manufacturers to enter the flexible thermoelectric
market.
For more information, contact Mick
Kulikowski at mick_kulikowski@ncsu.edu;
919-218-5937.
Wearable Device Captures Cancer Cells from Blood
By capturing more cancer cells than blood draw screening, this device could help doctors
understand a tumor's biology and make decisions about treatment.
University of Michigan, Ann Arbor
umors can release more than 1,000
cancer cells into the bloodstream in a
single minute. Current methods of capturing
cancer cells from blood rely on
samples from the patient - usually no
more than a tablespoon taken in a single
draw. Some blood draws come back with
no cancer cells, even in patients with
advanced cancer, and a typical sample
contains no more than 10 cancer cells.
A prototype wearable device was developed
that can continuously collect live
T
cancer cells directly from a patient's
blood. Over a couple of hours in the hospital,
the device could continuously capture
cancer cells directly from the vein,
screening much larger volumes of a
patient's blood. In tests, the cell-grabbing
chip in the wearable device trapped
3.5 times as many cancer cells per milliliter
of blood compared to the traditional
blood draw samples.
Research shows that most cancer cells
can't survive in the bloodstream, but
those that do are more likely to start a
new tumor. Typically, it is these satellite
tumors, called metastases, that are deadly,
rather than the original tumor. This
means cancer cells captured from blood
could provide better information for
planning treatments than those from a
conventional biopsy.
The device shrinks a machine that is
typically the size of an oven down to something
that could be worn on the wrist and
connected to a vein in the arm. Protocols
were developed for mixing the blood with
heparin, a drug that prevents clotting,
and sterilization methods that killed bacteria
without harming the cell-targeting
immune markers, or antibodies, on the
chip. Some of the smallest medical-grade
pumps were packaged in a 3D-printed
box with the electronics and the cancercell-capturing
chip.
The chip uses the nanomaterial graph -
ene oxide to create dense forests of antiThe
green circuit board inside the device controls the blood pump, heparin injector, and display
data. (Illustration: Tae Hyun Kim)
Tech Briefs, August 2021
Cov
www.techbriefs.com
ToC
body-tipped molecular chains, en abling
it to trap more than 80 percent of the
cancer cells in whole blood that flows
across it. The chip can also be used to
grow the captured cancer cells, producing
larger samples for further analysis.
In the next steps for the device, the
team hopes to increase the blood processing
rate. The device could begin human
trials in three to five years. It would be
used to help to optimize treatments for
human cancers by enabling doctors to
see if the cancer cells are making the molecules
that serve as targets for many
newer cancer drugs.
For more information, contact Katherine
McAlpine at kmca@umich.edu; 734-763-2937.
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Tech Briefs Magazine - August 2021

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