Transcript Document
Identifiction of IBD using an
electronic ‘e’ nose
Arasaradnam RP1,2, Ouaret N3, Nwokolo C1, Bardhan KD4,
Covington JA3
1University Hospital Coventry & Warwickshire &
2Clinical Sciences Research Institute, Medical School,
University of Warwick
3School of Engineering, University of Warwick, 4Rotherham NHS Trust
10th BROAD Meeting – February 2012
1
The Senses
5 Senses by Aristotle
Sight
Hearing
Smell
Taste
Touch
But also…
Nociception (pain)
Equilibrioception (balance)
Proprioception & kinesthesia
(joint motion and acceleration)
Sense of time
Thermoception (temperature
differences)
Magnetoception (direction)
‘Smell’ @ Warwick
First research group dedicated to the sense of smell
First company making artificial olfaction instruments
First commercial products manufactured here…
Long history of smell research…
Life in ‘Smell’
Persaud & Dodd Nature 1982
Sniffing diseases..…
Electronic Nose
Human olfactory system
Axel & Buck Nobel Prize 2004
How does it work?
Array of sensors with different broad sensitivity e.g. Alcohols
Operate by measuring change in
resistance/capacitance/frequency
ee- e-
e-
ee-
e-
e-
ee-
e-
e-
ee-
e- e
e-
If
a different
compound
causedby
thea air
to change,
the output
Each
sensor changes
its had
resistance
different
amount,
makingpattern
a pattern
Measurement
of baseline resistance
will
different:
of
thebechange
Electronic noses
Gas emissions and
Manufacturing processes
Food and cosmetics
Applications of
Electronic nose
Environmental
pollutants
Homeland security
Medical
applications
Sampling
Disease alters gut flora -
altered fermentation patterns
which alters the composition
of gases emitted from urine
Urine headspace measured
using an electronic nose and
FAIMS (field asymmetric ion
mobility spectrometry)
Novel method – non invasive
Possible faster and earlier
detection of IBD
Methods
• 48 patients and 14 volunteers; n = 62
• UC (n=20; active n=4), CD (n=20; active n=4) and
14 controls
• Urine analysis with ‘e’ nose and FAIMS
• Analysis was by Principal Component Analysis
(PCA) – not pre-classified and LDA (Linear
Discriminant Analysis) (pre-classified)
E - nose
Warwick Electronic Nose
Sample air is passed over sensors (300 secs)
followed by clean air (300 secs)
Filtered air is passed over
sample (1 L/min), capturing gas/vapours
emanating from the sample
10 ml of sample, placed in a sterilin bottle & heated to 40 oC
Separation of IBD with ‘E’ nose
Arasaradnam et al JMET 2011
Can we detect IBD by measuring Volatile organic
compounds/ gasses?
Arasaradnam et al 2010
FAIMS – Field Asymetric Ion Mobility
Spectrometry
Simple fast analysis of vapours
and gases
Detects chemicals in complex
mixtures
Identifies by mobility (ion
movement through an electric
field)
Mobility determined by
molecule size and mass
Chemicals identified and
separated
Can train to identify anomalies
Creates a chemical fingerprint
FAIMS
Covington et al 2011
IBD flare v remission
What are we detecting?
Summary of chemical peaks in volunteers and Crohns and UC
patients
Total OA (TOA)
Volunteer (V)
Time
/Patient (Pt) (weeks)
146 ± 6
V
CD
UC
Peaks (n)
Ratio
HA:AA:PG
1 : 1 : 0.05
Total A, K
(TAK)
(%)
7.5 ± 1.5
26 ± 6
(%)
0
164
1 : 1: 0.2
12
10
2
151
1:1:2
20
12
6
145
1 : 1.4 : 0.3
15
8
0
146
1 : 0.8 : 0.05
9
15
3
156
1 : 1.7 : 0.1
20
22
HA=hydrogen azide (HN3); AA=acetic acid (CH3COOH); PG=propylene glycol (C3H6(OH)2);
A=aldehydes; K=ketones; OA=organic acids.
Summary
o Potential alternate diagnosis method
o Able to distinguish between control and IBD patient
groups
o Can also identify specific disease groups ulcerative
colitis and Crohn’s
o Greatest difference is shown between diseased and
non-diseased
o FAIMS can also be used to identify diseased groups
and supports e nose data
Thank you - Questions
Acknowledgements:
BROAD Foundation
the future.......?