Medical Design Briefs - February 2021 - 26

Antimicrobial Ag*
Decreasing Bacterial
Toxin Production
1.2
Background
0 min Ag*
10 min Ag*
30 min Ag*

Current (μA)

0.9

0.6

0.3

0.0

Carbon Ultramicroelectrode Arrays
on a Flexible Substrate

-0.8

-0.6

-0.4

-0.2

0.0

Potential (V vs. SCE)

Cellular Culture in
Wound Simulant
Redox Bacterial Toxins

Fast Detection

Fig. 1 - The researchers built an early prototype of an electroanalytical wound sensor based on carbon ultra-microelectrode arrays on flexible substrates. (Credit: Olja Simoska et al./ACS sensors)

in complex biofluid simulants that closely mimic real biological environments, "
Stevenson says.
For the new study, the researchers
built an early prototype of an electroanalytical wound sensor based on carbon
ultra-microelectrode arrays (CUAs) on
flexible substrates (see Figure 1). In previous studies, this sensor had been
placed on quartz substrates, but to
ensure flexibility, the authors developed

a method of putting the arrays on a polyethylene terephthalate (PET) substrate.
The team used a simulated wound
environment to test the sensitivity of
their sensor to three critical biomarkers:
pyocyanin, produced by Pseudomonas
aeruginosa, a bacterium typically colonizing chronic wounds; nitric oxide (NO*)
secreted in response to bacterial infections by cells of the immune system; and
uric acid, a metabolite that strongly cor-

relates with the severity of a wound. All
these compounds are electroactive; that
is, they respond to electrical activity and
thus can be detected by an electroanalytical sensor.
Testing showed that both the sensor's limits of detection and linear
dynamic ranges, which represent the
ranges of concentrations where a sensor produces meaningful quantitative
results, were within the biologically
relevant concentrations - that means
a device based on these sensors could
be used for wound monitoring in a
clinical setting.
The researchers also tested their
electroanalytical wound sensor in cell
cultures, where it successfully detected
pyocyanin from P. aeruginosa and NO*
from macrophages (immune cells that
destroy bacteria and other " invaders " ).
Finally, the sensor was also able to
detect the influence of Ag+ silver ions,
a known antimicrobial agent, that suppressed pyocyanin production by the
bacteria.
" The next step is to utilize this sensor
technology for in vivo studies and realtime monitoring of wound treatment
effectiveness on human subjects in clinical settings, " Stevenson notes.
For more information, visit https://
www.skoltech.ru/en.

Chipset-Specific IPDs Simplify Development of Next-Gen
Wireless Medical IoT Applications
Miniaturized, front-end
IPDs are specifically
designed to seamlessly
connect.
Johanson Technology
Camarillo, CA
For the next generation of low-cost,
battery operated, wireless IoT products,
the design goal is to provide exceptional
RF signal range and stability, while also
reducing power consumption, in a
miniaturized package. As a result, RF
chipset and component manufacturers
are increasingly fine-tuning and improving their products to do just that.
According to Semtech, LoRa® and
LoRaWAN® are already the " de facto
technology for Internet of Things (IoT)
networks worldwide, " and these technologies will provide long-range connec-

An integrated passive device (IPD) makes the final PCB size smaller and simpler. (Credit: Johanson
Technology)

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Medical Design Briefs - February 2021

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