<s>
A	O
chemical	B-Algorithm
sensor	I-Algorithm
array	I-Algorithm
is	O
a	O
sensor	O
architecture	O
with	O
multiple	O
sensor	O
components	O
that	O
create	O
a	O
pattern	O
for	O
analyte	O
detection	O
from	O
the	O
additive	O
responses	O
of	O
individual	O
sensor	O
components	O
.	O
</s>
<s>
There	O
exist	O
several	O
types	O
of	O
chemical	B-Algorithm
sensor	I-Algorithm
arrays	I-Algorithm
including	O
electronic	O
,	O
optical	O
,	O
acoustic	O
wave	O
,	O
and	O
potentiometric	O
devices	O
.	O
</s>
<s>
These	O
chemical	B-Algorithm
sensor	I-Algorithm
arrays	I-Algorithm
can	O
employ	O
multiple	O
sensor	O
types	O
that	O
are	O
cross-reactive	O
or	O
tuned	O
to	O
sense	O
specific	O
analytes	O
.	O
</s>
<s>
Chemical	B-Algorithm
sensor	I-Algorithm
arrays	I-Algorithm
differ	O
from	O
other	O
multianalyte	O
tests	O
such	O
as	O
a	O
urinalysis	O
stick	O
assay	O
which	O
utilizes	O
multiple	O
,	O
specific	O
sensor	O
materials	O
for	O
targeted	O
detection	O
of	O
analytes	O
in	O
a	O
mixture	O
;	O
instead	O
,	O
chemical	B-Algorithm
sensor	I-Algorithm
arrays	I-Algorithm
rely	O
on	O
cross-reactivity	O
of	O
individual	O
sensor	O
components	O
to	O
generate	O
fingerprints	O
based	O
on	O
the	O
additive	O
responses	O
of	O
sensor	O
components	O
to	O
the	O
target	O
analyte	O
.	O
</s>
<s>
Chemical	B-Algorithm
sensor	I-Algorithm
arrays	I-Algorithm
employ	O
pattern	O
recognition	O
of	O
combinatorial	O
responses	O
of	O
cross-reactive	O
sensor	O
components	O
to	O
enable	O
sensing	O
of	O
a	O
diverse	O
array	O
of	O
mixtures	O
in	O
a	O
variety	O
of	O
conditions	O
.	O
</s>
<s>
Chemical	B-Algorithm
sensor	I-Algorithm
arrays	I-Algorithm
are	O
often	O
noted	O
as	O
mimicking	O
the	O
five	O
senses	O
—	O
audition	O
,	O
gustation	O
,	O
olfaction	O
,	O
somatosensation	O
,	O
and	O
vision	O
—	O
because	O
the	O
combinatorial	O
responses	O
to	O
the	O
different	O
array	O
components	O
of	O
a	O
particular	O
analytes	O
create	O
fingerprints	O
for	O
specific	O
analytes	O
or	O
mixtures	O
using	O
both	O
targeted	O
molecular	O
interactions	O
and	O
pattern	O
recognition	O
.	O
</s>
<s>
The	O
history	O
of	O
chemical	B-Algorithm
sensor	I-Algorithm
arrays	I-Algorithm
is	O
closely	O
linked	O
with	O
the	O
development	O
of	O
other	O
chemical	O
sensor	O
technologies	O
,	O
with	O
research	O
in	O
the	O
area	O
of	O
electronic	O
chemical	O
sensors	O
picking	O
up	O
in	O
the	O
1960s	O
with	O
the	O
demonstration	O
of	O
metal-oxide	O
semiconductor	O
sensors	O
capable	O
of	O
sensing	O
analyses	O
such	O
as	O
oxygen	O
.	O
</s>
<s>
One	O
of	O
the	O
design	O
aims	O
of	O
many	O
chemical	B-Algorithm
sensor	I-Algorithm
arrays	I-Algorithm
is	O
to	O
mimic	O
the	O
performance	O
of	O
olfaction	O
to	O
design	O
an	O
electronic	O
nose	O
integrated	O
with	O
a	O
variety	O
of	O
materials	O
.	O
</s>
<s>
Combining	O
chemical	B-Algorithm
sensor	I-Algorithm
arrays	I-Algorithm
with	O
pattern	O
recognition	O
methods	O
mimics	O
biological	O
sensory	O
recognition	O
methods	O
.	O
</s>
<s>
At	O
the	O
center	O
of	O
chemical	B-Algorithm
sensor	I-Algorithm
arrays	I-Algorithm
is	O
the	O
principle	O
that	O
different	O
analytes	O
will	O
interact	O
differently	O
with	O
a	O
variety	O
of	O
materials	O
.	O
</s>
<s>
From	O
this	O
idea	O
,	O
cross-reactive	O
sensor	O
arrays	O
have	O
been	O
the	O
focus	O
of	O
chemical	B-Algorithm
sensor	I-Algorithm
array	I-Algorithm
development	O
for	O
their	O
broad	O
compatibility	O
with	O
the	O
compounds	O
as	O
components	O
of	O
mixtures	O
.	O
</s>
<s>
Many	O
techniques	O
are	O
useful	O
in	O
processing	O
array	O
data	O
including	O
principal	B-Application
component	I-Application
analysis	I-Application
(	O
PCA	O
)	O
,	O
least	B-Algorithm
square	I-Algorithm
analysis	I-Algorithm
,	O
and	O
more	O
recently	O
training	O
of	O
neural	B-Architecture
networks	I-Architecture
and	O
utilization	O
of	O
machine	O
learning	O
for	O
pattern	O
development	O
and	O
identification	O
.	O
</s>
<s>
Machine	O
learning	O
has	O
been	O
a	O
more	O
recent	O
development	O
for	O
generation	O
and	O
recognition	O
of	O
patterns	O
for	O
chemical	B-Algorithm
sensor	I-Algorithm
array	I-Algorithm
data	O
.	O
</s>
<s>
The	O
method	O
of	O
data	O
analysis	O
chosen	O
depends	O
on	O
a	O
variety	O
of	O
factors	O
including	O
sensing	O
parameters	O
,	O
desired	O
use	O
of	O
the	O
information	O
(	O
quantitative	O
or	O
qualitative	O
)	O
,	O
and	O
the	O
method	O
of	O
detection	O
which	O
can	O
be	O
classified	O
under	O
four	O
major	O
types	O
of	O
chemical	B-Algorithm
sensor	I-Algorithm
array	I-Algorithm
:	O
electronic	O
,	O
optical	O
,	O
acoustic	O
wave	O
,	O
and	O
electrochemical	O
sensor	O
arrays	O
.	O
</s>
<s>
The	O
first	O
type	O
of	O
chemical	B-Algorithm
sensor	I-Algorithm
array	I-Algorithm
relies	O
on	O
modulation	O
of	O
an	O
electronic	O
signal	O
for	O
signal	O
acquisition	O
.	O
</s>
<s>
This	O
type	O
of	O
chemical	B-Algorithm
sensor	I-Algorithm
array	I-Algorithm
often	O
utilizes	O
a	O
semiconductive	O
material	O
such	O
as	O
metal-oxide	B-Architecture
semiconductors	I-Architecture
,	O
conductive	B-Algorithm
polymers	I-Algorithm
,	O
nanomaterials	O
,	O
or	O
framework	O
materials	O
such	O
as	O
metal-organic	O
and	O
covalent-organic	O
frameworks	O
.	O
</s>
<s>
One	O
of	O
the	O
simplest	O
device	O
architectures	O
for	O
an	O
electronic	O
chemical	O
sensor	O
is	O
a	O
chemiresistor	B-Algorithm
,	O
and	O
other	O
architectures	O
include	O
capacitors	O
and	O
transistors	O
;	O
these	O
materials	O
have	O
a	O
resistance	O
which	O
can	O
be	O
altered	O
through	O
physisorption	O
or	O
chemisorption	O
of	O
target	O
molecules	O
and	O
thus	O
a	O
measurable	O
signal	O
as	O
a	O
change	O
in	O
electrical	O
current	O
,	O
capacitance	O
,	O
or	O
voltage	O
.	O
</s>
<s>
Metal-oxide	B-Architecture
semiconductors	I-Architecture
were	O
first	O
reported	O
in	O
the	O
1960s	O
as	O
a	O
chemiresistor	B-Algorithm
sensor	O
for	O
single-analyte	O
detection	O
of	O
organic	O
vapors	O
.	O
</s>
<s>
The	O
first	O
commercially	O
available	O
chemiresistive	O
sensors	O
utilized	O
metal-oxide	B-Architecture
semiconductors	I-Architecture
for	O
the	O
detection	O
of	O
carbon	O
monoxide	O
.	O
</s>
<s>
Although	O
most	O
known	O
for	O
their	O
use	O
in	O
carbon	O
monoxide	O
detectors	O
,	O
metal-oxide	B-Architecture
semiconductors	I-Architecture
are	O
capable	O
of	O
sensing	O
other	O
analytes	O
through	O
strategic	O
tuning	O
of	O
their	O
composition	O
.	O
</s>
<s>
Sensitivity	O
of	O
sensors	O
has	O
also	O
been	O
shown	O
to	O
be	O
influenced	O
by	O
changing	O
the	O
ratio	O
of	O
the	O
metal	O
within	O
each	O
device	O
and	O
data	O
processing	O
utilized	O
least	B-Algorithm
square	I-Algorithm
analysis	I-Algorithm
.	O
</s>
<s>
Another	O
example	O
of	O
metal-oxide	B-Architecture
semiconductors	I-Architecture
is	O
arrays	O
of	O
metal-oxide	B-Architecture
semiconductor	I-Architecture
field	I-Architecture
effect	I-Architecture
transistors	I-Architecture
(	O
MOSFET	B-Architecture
)	O
,	O
which	O
consist	O
of	O
a	O
catalytically	O
active	O
gate	O
metal	O
(	O
such	O
as	O
palladium	O
)	O
over	O
a	O
silicon	O
dioxide	O
layer	O
on	O
a	O
p-type	O
silicon	O
base	O
with	O
n-doped	O
channels	O
adjacent	O
to	O
the	O
gate	O
,	O
and	O
they	O
have	O
been	O
used	O
to	O
sense	O
hydrogen	O
,	O
ammonia	O
,	O
and	O
ethanol	O
.	O
</s>
<s>
These	O
MOSFETs	B-Architecture
through	O
adsorbed-analyte	O
modulating	O
the	O
semiconductor	O
gate	O
work	O
function	O
,	O
which	O
causes	O
changes	O
in	O
voltage	O
across	O
the	O
device	O
.	O
</s>
<s>
MOSFETs	B-Architecture
are	O
highly	O
tunable	O
but	O
remain	O
limited	O
by	O
their	O
cross-reactivity	O
,	O
and	O
high	O
operating	O
temperatures	O
.	O
</s>
<s>
Several	O
intrinsically	B-Algorithm
conductive	I-Algorithm
polymers	I-Algorithm
of	O
interest	O
include	O
polyacetylene	B-Language
,	O
polythiophene	B-Algorithm
,	O
and	O
polyaniline	B-Algorithm
,	O
and	O
others	O
may	O
be	O
made	O
conductive	O
through	O
processes	O
including	O
chemical	B-Algorithm
doping	I-Algorithm
.	O
</s>
<s>
The	O
principle	O
chemistry	O
underlying	O
the	O
electronic	O
sensing	O
mechanism	O
of	O
conductive	B-Algorithm
polymers	I-Algorithm
is	O
modulation	O
of	O
the	O
conductivity	O
of	O
these	O
polymers	O
upon	O
changes	O
to	O
their	O
physical	O
structure	O
(	O
swelling	O
)	O
resulting	O
from	O
interactions	O
with	O
analytes	O
(	O
mainly	O
through	O
absorption	O
)	O
.	O
</s>
<s>
An	O
advantage	O
of	O
using	O
conductive	B-Algorithm
polymers	I-Algorithm
in	O
sensor	O
arrays	O
is	O
that	O
there	O
is	O
synthetic	O
access	O
of	O
a	O
vast	O
library	O
of	O
polymers	O
.	O
</s>
<s>
As	O
a	O
result	O
,	O
conductive	B-Algorithm
polymers	I-Algorithm
are	O
a	O
promising	O
alternative	O
to	O
metal-oxide	B-Architecture
semiconductors	I-Architecture
because	O
a	O
greater	O
number	O
of	O
sensors	O
with	O
different	O
functionalities	O
may	O
be	O
used	O
to	O
design	O
a	O
more	O
robust	O
array	O
tailored	O
for	O
specific	O
applications	O
.	O
</s>
<s>
Monomer	O
identity	O
,	O
polymerization	O
conditions	O
,	O
and	O
device	O
fabrication	O
methods	O
impact	O
both	O
the	O
morphological	O
and	O
chemical	O
properties	O
of	O
conductive	B-Algorithm
polymers	I-Algorithm
,	O
which	O
also	O
contributes	O
to	O
the	O
greater	O
variety	O
of	O
possible	O
array	O
components	O
which	O
may	O
be	O
designed	O
.	O
</s>
<s>
The	O
limitations	O
of	O
conductive	B-Algorithm
polymer	I-Algorithm
arrays	O
are	O
similar	O
to	O
those	O
of	O
single	O
sensor	O
analogs	O
in	O
that	O
the	O
signal	O
transduction	O
pathways	O
through	O
the	O
polymer	O
material	O
are	O
poorly	O
understood	O
and	O
both	O
struggle	O
to	O
sense	O
non-polar	O
species	O
due	O
to	O
minimal	O
adsorption	O
to	O
the	O
polymer	O
.	O
</s>
<s>
Several	O
commercially	O
available	O
systems	O
are	O
available	O
and	O
are	O
used	O
in	O
food	O
analysis	O
and	O
sensing	O
of	O
volatile	O
organic	O
compounds	O
;	O
however	O
,	O
progress	O
to	O
advance	O
chemiresistive	O
sensor	O
arrays	O
utilizing	O
conductive	B-Algorithm
polymers	I-Algorithm
has	O
decreased	O
as	O
other	O
materials	O
and	O
sensing	O
methods	O
have	O
been	O
developed	O
.	O
</s>
<s>
Development	O
of	O
novel	O
nanomaterials	O
such	O
as	O
graphene	O
,	O
carbon	O
nanotubes	O
,	O
and	O
2D	O
and	O
3D	O
framework	O
materials	O
have	O
been	O
reported	O
as	O
new	O
classes	O
of	O
materials	O
for	O
applications	O
in	O
electronic	O
chemical	B-Algorithm
sensor	I-Algorithm
arrays	I-Algorithm
.	O
</s>
<s>
Bimetallic	O
metallophthalocyanine	O
metal-organic	O
frameworks	O
(	O
MOFs	O
)	O
and	O
covalent	O
organic	O
frameworks	O
(	O
COFs	O
)	O
have	O
shown	O
promise	O
in	O
single	O
device	O
chemiresistors	B-Algorithm
at	O
sensing	O
hydrogen	O
sulfide	O
,	O
ammonia	O
,	O
and	O
nitric	O
oxide	O
.	O
</s>
<s>
The	O
development	O
of	O
these	O
materials	O
as	O
chemiresistors	B-Algorithm
allows	O
for	O
strategic	O
design	O
of	O
arrays	O
capable	O
of	O
targeted	O
molecular	O
interactions	O
,	O
which	O
can	O
be	O
employed	O
to	O
develop	O
array	O
components	O
tailored	O
to	O
sensing	O
specific	O
compounds	O
.	O
</s>
<s>
Efforts	O
have	O
been	O
made	O
to	O
overcome	O
the	O
specific	O
limitations	O
of	O
different	O
classes	O
of	O
materials	O
suited	O
for	O
use	O
in	O
electronic	O
chemical	B-Algorithm
sensor	I-Algorithm
arrays	I-Algorithm
by	O
combining	O
sensors	O
fabricated	O
with	O
different	O
materials	O
into	O
one	O
array	O
.	O
</s>
<s>
Separate	O
from	O
electronic	O
chemical	B-Algorithm
sensor	I-Algorithm
arrays	I-Algorithm
are	O
optical	O
chemical	B-Algorithm
sensor	I-Algorithm
arrays	I-Algorithm
which	O
probe	O
chemical	O
interactions	O
between	O
target	O
analytes	O
and	O
a	O
sensing	O
material	O
with	O
light	O
(	O
ultraviolet	B-Application
,	O
visible	O
,	O
infrared	O
)	O
.	O
</s>
<s>
Similar	O
to	O
the	O
electronic	O
nose	O
,	O
optical	O
chemical	B-Algorithm
sensor	I-Algorithm
arrays	I-Algorithm
have	O
been	O
categorized	O
under	O
the	O
umbrella	O
topic	O
of	O
optoelectronic	O
nose	O
and	O
similarly	O
operate	O
by	O
developing	O
fingerprints	O
for	O
specific	O
compounds	O
and	O
using	O
pattern	O
recognition	O
to	O
identify	O
those	O
components	O
in	O
mixture	O
.	O
</s>
<s>
Much	O
like	O
electrical	O
chemical	B-Algorithm
sensor	I-Algorithm
arrays	I-Algorithm
,	O
optical	O
chemical	B-Algorithm
sensor	I-Algorithm
arrays	I-Algorithm
face	O
challenges	O
in	O
sensing	O
in	O
the	O
presence	O
of	O
competing	O
analytes	O
such	O
as	O
water	O
.	O
</s>
<s>
While	O
Brønsted-Lowry	O
acid-base	O
interactions	O
are	O
sensitive	O
to	O
a	O
broad	O
range	O
of	O
compounds	O
,	O
Lewis	O
acid	O
and	O
base	O
interactions	O
comprise	O
some	O
of	O
the	O
most	O
sensitive	O
set	O
of	O
intermolecular	O
interactions	O
relevant	O
to	O
colorimetric	O
chemical	B-Algorithm
sensor	I-Algorithm
arrays	I-Algorithm
.	O
</s>
<s>
These	O
include	O
redox	B-Operating_System
active	O
chromo	O
-	O
and	O
fluorophores	O
which	O
undergo	O
specific	O
color	O
changes	O
at	O
different	O
applied	O
potentials	O
.	O
</s>
<s>
Nanomaterials	O
development	O
has	O
allowed	O
for	O
surface	O
modification	O
of	O
certain	O
dyes	O
(	O
especially	O
redox	B-Operating_System
active	O
dyes	O
)	O
to	O
afford	O
high	O
sensitivity	O
due	O
to	O
larger	O
surface	O
area-to-volume	O
ratio	O
resulting	O
for	O
more	O
active	O
sites	O
for	O
analyte	O
interaction	O
with	O
dyes	O
.	O
</s>
<s>
Unlike	O
the	O
materials	O
used	O
in	O
electronic	O
chemical	B-Algorithm
sensor	I-Algorithm
arrays	I-Algorithm
,	O
in	O
which	O
direct	O
interaction	O
between	O
the	O
sensing	O
material	O
and	O
an	O
analyte	O
leads	O
to	O
signal	O
transduction	O
as	O
a	O
change	O
in	O
conductivity	O
or	O
voltage	O
,	O
fabrication	O
of	O
colorimetric	O
sensor	O
arrays	O
requires	O
consideration	O
of	O
both	O
analyte-substrate	O
interaction	O
and	O
transduction	O
of	O
the	O
optical	O
signal	O
.	O
</s>
<s>
These	O
microspheres	O
are	O
then	O
incorporated	O
into	O
fiber	B-Architecture
optics	I-Architecture
.	O
</s>
<s>
Inclusion	O
of	O
digital	B-Algorithm
imaging	I-Algorithm
and	O
or	O
illumination	O
of	O
optical	O
chemical	B-Algorithm
sensor	I-Algorithm
array	I-Algorithm
elements	O
allows	O
for	O
rapid	O
,	O
real-time	O
signal	O
transduction	O
of	O
colorimetric	O
data	O
measurements	O
in	O
real-time	O
of	O
colorimetric	O
and	O
fluorescent	O
data	O
from	O
microsphere	O
or	O
plated	O
sensors	O
.	O
</s>
<s>
Much	O
like	O
electronic	O
chemical	B-Algorithm
sensor	I-Algorithm
arrays	I-Algorithm
,	O
optical	O
chemical	B-Algorithm
sensor	I-Algorithm
arrays	I-Algorithm
are	O
being	O
miniaturized	O
using	O
microfabrication	O
techniques	O
to	O
increase	O
the	O
applicability	O
.	O
</s>
<s>
Recent	O
advancements	O
in	O
optical	O
chemical	B-Algorithm
sensor	I-Algorithm
arrays	I-Algorithm
have	O
resulted	O
in	O
sensor	O
arrays	O
being	O
directly	O
integrated	O
into	O
flatbed	B-Application
scanners	I-Application
and	O
mobile	O
electronics	O
such	O
as	O
smart	O
phones	O
(	O
through	O
microplate	O
fabrication	O
)	O
.	O
</s>
<s>
Although	O
less	O
common	O
,	O
there	O
are	O
two	O
other	O
classifications	O
of	O
devices	O
with	O
demonstrated	O
functionality	O
as	O
chemical	B-Algorithm
sensor	I-Algorithm
arrays	I-Algorithm
.	O
</s>
<s>
These	O
devices	O
may	O
be	O
modified	O
with	O
the	O
plurality	O
of	O
the	O
materials	O
already	O
discussed	O
as	O
being	O
useful	O
materials	O
in	O
chemical	B-Algorithm
sensor	I-Algorithm
array	I-Algorithm
.	O
</s>
<s>
Bulk	O
and	O
surface	O
acoustic	O
wave	O
devices	O
have	O
used	O
in	O
higher	O
order	O
sensors	O
in	O
which	O
the	O
sensing	O
material	O
gives	O
rise	O
to	O
multiple	O
modes	O
for	O
signal	O
transduction	O
,	O
such	O
as	O
electrical	O
and	O
optical	O
;	O
additionally	O
the	O
same	O
wave	O
devices	O
have	O
also	O
been	O
used	O
to	O
create	O
virtual	O
chemical	B-Algorithm
sensor	I-Algorithm
arrays	I-Algorithm
,	O
in	O
which	O
data	O
from	O
one	O
sensor	O
component	O
is	O
further	O
processed	O
.	O
</s>
<s>
A	O
chemical	B-Algorithm
sensor	I-Algorithm
array	I-Algorithm
of	O
surface-modified	O
quartz	O
crystal	O
microbalances	O
with	O
a	O
variety	O
of	O
materials	O
including	O
copper	O
phthalocyanine	O
,	O
single	O
-	O
and	O
multi-walled	O
carbon	O
nanotubes	O
was	O
shown	O
as	O
a	O
promising	O
electronic	O
nose	O
for	O
gas	O
sensing	O
when	O
machine	O
learning	O
algorithms	O
were	O
employed	O
for	O
data	O
processing	O
.	O
</s>
<s>
Another	O
class	O
of	O
devices	O
usable	O
in	O
chemical	B-Algorithm
sensor	I-Algorithm
arrays	I-Algorithm
are	O
electrodes	O
.	O
</s>
<s>
Both	O
voltametric	O
and	O
potentiometric	O
methods	O
have	O
been	O
developed	O
,	O
and	O
this	O
technique	O
is	O
an	O
active	O
area	O
of	O
research	O
not	O
only	O
for	O
multianalyte	O
analysis	O
of	O
aqueous	O
solutions	O
such	O
as	O
cerebrospinal	O
fluid	O
,	O
but	O
also	O
differentiation	O
of	O
redox	B-Operating_System
products	O
in	O
electrochemical	O
reactions	O
.	O
</s>
<s>
There	O
exists	O
a	O
diversity	O
of	O
well-understood	O
,	O
and	O
emerging	O
research	O
focused	O
on	O
developing	O
chemical	B-Algorithm
sensor	I-Algorithm
arrays	I-Algorithm
for	O
a	O
variety	O
of	O
applications	O
.	O
</s>
<s>
Analytical	O
devices	O
integrated	O
with	O
a	O
chemical	B-Algorithm
sensor	I-Algorithm
array	I-Algorithm
have	O
been	O
proposed	O
as	O
diagnostic	O
tests	O
for	O
cancer	O
,	O
bacterial	O
infections	O
based	O
on	O
fingerprint	O
analysis	O
of	O
exhaled	O
breath	O
,	O
as	O
well	O
as	O
for	O
food	O
and	O
product	O
quality	O
control	O
.	O
</s>
<s>
Clinical	O
trial	O
of	O
a	O
chemical	B-Algorithm
sensor	I-Algorithm
array	I-Algorithm
device	O
made	O
with	O
gold	O
nanoparticles	O
linked	O
with	O
different	O
organic	O
ligands	O
capable	O
of	O
detecting	O
COVID-19	O
infections	O
.	O
</s>
<s>
The	O
Handheld	O
Electronic	O
Nose	O
(	O
HEN	O
)	O
commercial	O
chemical	B-Algorithm
sensor	I-Algorithm
array	I-Algorithm
device	O
which	O
enables	O
optimization	O
of	O
the	O
fermentation	O
of	O
tea	O
,	O
see	O
Figure	O
3	O
.	O
</s>
<s>
The	O
WOLF	O
eNose	O
is	O
a	O
commercially	O
available	O
system	O
of	O
chemical	B-Algorithm
sensor	I-Algorithm
arrays	I-Algorithm
using	O
both	O
electronic	O
and	O
colorimetric	O
sensors	O
for	O
the	O
detection	O
of	O
volatile	O
organic	O
compounds	O
,	O
and	O
it	O
has	O
been	O
employed	O
for	O
detection	O
of	O
urinary	O
tract	O
infection-causing	O
bacteria	O
.	O
</s>
<s>
The	O
Cyranose	O
320	O
Electronic	O
Nose	O
is	O
a	O
commercially	O
available	O
chemical	B-Algorithm
sensor	I-Algorithm
array	I-Algorithm
fabricated	O
from	O
32	O
black	O
carbon-polymer	O
sensors	O
capable	O
of	O
identifying	O
six	O
bacteria	O
that	O
cause	O
eye	O
infections	O
with	O
96%	O
accuracy	O
,	O
see	O
Figure	O
4	O
.	O
</s>
