Medical Design Briefs - June 2021 - 18

Next-Gen POC Diagnostics
Fig. 3 - The electrochemistry chip ADuCM355 by Analog Devices is part of the EmStat Pico potentiostat
module, which was used to build the handheld, Bluetooth-operated potentiostat Sensit BT.
of common electrochemical techniques
and advanced techniques like electrochemical
impedance spectroscopy (EIS).
While having the size of a common glucose
meter, these devices offer more
functionalities and are more versatile.
EIS is a very interface-sensitive technique,
which allows among other applications
label-free detection of biomolecules
for example DNA.1 It is no surprise
that in 2021 these compact potentiostats
were also used for different SARS-CoV-2
detection systems.2-5 While the academic
world reacted swiftly and developed
many new detection methods for SARSCoV-2,
the translation of the proof of
principles into a commercial product is
a challenging task. Developing a dedicated
device including electronics design,
firmware, and software requires a team
of specialized staff and time.
Commercial solutions that support
this translation are available as well. The
Fig. 4 - Potentiostat module on a development board (left), modular potentiostat (middle, right).
Another reason for long development times is software development. Potentiostat modules often
have specialized firmware and software development kits (SDK) which allow writing simple user interfaces
in a short amount of time, because the communication with potentiostat itself is simplified.
The software developer is in full control without learning the details on a circuitry level.
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Fig. 5 - Block diagram of an IVD system.
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IVD System Architecture
Let's take a closer look at what's in the
box of a typical EC system and the tradeoffs
needed when creating a requirements
document for a new meter
design. System power management is
typically a good starting point in any new
design (see Figure 5). The number of
tests a meter will need to perform, along
with the timing, voltages, and currents
of those tests and communication
(wired/wireless/display/sound) will de -
fine the capacity requirements for the
battery.
Many home glucose meters on the
market today use 3 V CR2032 batteries, as
they are small and provide sufficient
power of 250 mAHr to support up to a
year of daily testing with each test lasting
less than 5 seconds. For example, if the
Medical Design Briefs, June 2021
development can be accelerated by
using potentiostat modules. Instead of
designing your own potentiostats and
firmware, potentiostat modules provide
the electrochemical methods of the
measurement system. Another option is
to use modular potentiostats, which can
be changed into an individual product
with just a few customizations. The simplest
version of such a solution is just
exchanging the logo on the device.
More advanced solutions allow modification
of the electrode connection, as well
as offering battery and Bluetooth op -
tions and customized keypads. Such
turnkey electronic design services allow
having prototypes of a reader within a
few months (see Figure 4).

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Medical Design Briefs - June 2021

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