NEWS & TECHNOLOGY FLEXIBLE ELECTRONICS
Flexible paper biobatteries are triggered by spit
By Nick Flaherty
Researchers at Binghamton University in New York state
have created a paper ‘biobattery’ activated by saliva.
The microbial fuel cells on a paper substrate can be
used to power point-of-care (POC) diagnostic biosensors.
“On-demand micro-power generation is required especially for
point-of-care diagnostic applications in developing countries,”
said Seokheun “Sean” Choi from the Electrical and Computer
Engineering Department. “Typically, those applications require
only several tens of microwatt-level power for several minutes,
but commercial batteries or other energy harvesting technologies
are too expensive and over-qualified. Also, they pose environmental
pollution issues.”
Choi, along with research assistant
Maedeh Mohammadifar,
created a high-performance,
paper-based, bacteria-powered
battery by building microbial fuel
cells (MFC) with inactive, freezedried
cells that generates power
within minutes of adding saliva.
“The proposed battery has
competitive advantages over
other conventional power solutions because the biological fluid
for on-demand battery activation is readily available even in
the most resource-constrained settings, and the freeze-drying
technology enables long-term storage of cells without degradation
or denaturation,” said Choi,
“Now, our power density is about a few microwatts per
centimeter square. Although 16 microbial fuel cells connected
in a series on a single sheet of paper generated desired values
of electrical current and voltage to power a light-emitting diode
(LED), further power improvement is required for other electronic
applications demanding hundreds of milliwatts of energy,”
said Choi.
This follows the development of a biodegradeable paper
biobattery that can be stacked to provide the necessary power.
“There’s been a dramatic increase in electronic waste and
this may be an excellent way to start reducing that,” said Choi.
“Our hybrid paper battery exhibited a
much higher power-to-cost ratio than all
previously reported paper-based microbial
batteries.”
The biobattery uses a hybrid of paper
and engineered polymers. The polymers
- poly (amic) acid and poly (pyromellitic
dianhydride-p-phenylenediamine) - allow
the battery to decompose. This was tested
in water, clearly biodegrading without the
need for special facilities, conditions or
introduction of other microorganisms.
The polymer-paper structures are lightweight, low-cost and
flexible and can be stacked to provide more power. “Power
enhancement can be potentially achieved by simply folding or
stacking the hybrid, flexible paper-polymer devices,” he said.
Flexible wearable customizes drug delivery upon diagnosis
By Julien Happich
Researchers from the Korea Advanced Institute of Science
& Technology (KAIST) have devised a flexible and
wearable drug delivery device enabling controlled drug
release for customized medicine based on the wearer’s physiological
data.
Theragnosis, the collection of accurate physiological metrics
to simultaneously diagnose a health condition and then offer
the most accurate treatment and personalized doses of medicines
is an emerging medical technology. Theragnosis devices
including smart contact lenses and microneedle patches which
integrate physiological data sensors and drug delivery devices.
For this microdevice, Professor Daesoo Kim from the Department
of Biological
Science and Professor
Keon Jae Lee
from the Department
of Materials
Science and Engineering
lead a team
to fabricate a device
on a rigid substrate
and transferred a
50 μm-thick active
drug delivery layer
to the flexible substrate
via inorganic
laser lift off.
While remaining mechanically flexible, the device retains
its capability to precisely administer exact dosages at desired
times. The core technology consists in producing a freestanding
gold capping layer directly on top of drug-filled microreservoirs.
The new flexible drug delivery system could be applied to
smart contact lenses or brain disease treatments as it can be
implanted and can conform to cramped and corrugated organs.
If powered wirelessly, it could offer a novel platform for personalized
medicine, the researchers anticipate. Through animal
experimentation, the
team demonstrated
the device could
improve brain epilepsy
treatments by
precisely and timely
releasing anti-epileptic
medication.
The study was
described in a paper
titled “Flexible Wireless
Powered Drug
Delivery System for
Targeted Administration
on Cerebral
Cortex” published in
the June online issue
of Nano Energy.
The flexible drug delivery device for
controlled release attached on a glass
rod.
Schematic view of the flexible drug
delivery micro-device, fabricated via
inorganic laser lift off.
24 News September 2018 @eeNewsEurope www.eenewseurope.com
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