This document summarizes Dr. Saidhbhe O'Riordan's research using electrochemical methods to monitor physiological biomarkers in real-time. Specifically, it discusses using sensors to detect hydrogen peroxide levels in rodent brains to study disorders like Parkinson's disease, and oxygen levels to evaluate muscle tissue viability and potentially translate this to human patients. The research aims to further understand disease pathogenesis and provide diagnostic tools. Key findings include characterizing a dual catalase-based sensor for detecting brain hydrogen peroxide levels in freely-moving animals and developing an oxygen sensor with potential for clinical use in monitoring brain and peripheral oxygen levels in rodents and eventually humans.

1. ELECTROCHEMICAL METHODS TO INVESTIGATE DISORDERS
OF THE BRAIN AND EVALUATE MUSCLE TISSUE VIABILITY;
REAL-TIME MONITORING OF PHYSIOLOGICAL BIOMARKERS.
Dr. Saidhbhe O’Riordan,
14th Apr, 2016

2. Outline
maynoothuniversity.ie
• What?
Hydrogen peroxide (H2O2), Oxygen (O2)
• Where?
Brain H2O2 , Muscle tissue O2
• Who?
Rodents H2O2 and O2, Clinical O2
• How?
Electrochemical real-time, instantaneous information
• Why?
Pathogenesis, Diagnostic
Animal models of disease e.g. PD, patients ischemia
14th April 2016 | Dr. Saidhbhe O’Riordan | DCU CASi

3. In-vitro
maynoothuniversity.ie14th April 2016 | Dr. Saidhbhe O’Riordan | DCU CASi

4. Sensors (in-vivo)
maynoothuniversity.ie14th April 2016 | Dr. Saidhbhe O’Riordan | DCU CASi

5. L.I.V.E. (in-vivo)
maynoothuniversity.ie14th April 2016 | Dr. Saidhbhe O’Riordan | DCU CASi

6. In-vivo characterisation of a dual catalase-
based biosensor for the real-time
electrochemical detection of brain hydrogen
peroxide in freely-moving animals.
SL O’Riordan1 and JP Lowry1
1Neurochemistry Research Unit, BioAnalytics Laboratory, Department of Chemistry, Maynooth University, Maynooth, Co.
Kildare, Ireland.
MANUSCRIPT IN PROGRESS

7. maynoothuniversity.ie
Sensitivity (MCS)
Baseline
1.35 ± 0.25 nA
Max
1.65 ± 0.31 nA
(P = 0.0414*)
n = 3
0 10 20 30 40 50 60 70
0.9
1.0
1.1
1.2
1.3
1.4
Time, min
I,nA
Baseline MCS max.
0.0
0.5
1.0
1.5
2.0
2.5
*
I,nA
14th April 2016 | Dr. Saidhbhe O’Riordan | DCU CASi

8. maynoothuniversity.ie
Selectivity (AA)
Baseline
0.95 ± 0.38 nA
Max
1.04 ± 0.42 nA
(P = 0.1043)
n = 6
0 5 10 15 20 25 30
0.6
0.7
0.8
0.9
1.0
Time, min
I,nA
Baseline AA max.
0.0
0.5
1.0
1.5
2.0
I,nA
14th April 2016 | Dr. Saidhbhe O’Riordan | DCU CASi

9. maynoothuniversity.ie
Stability (in-vivo)
Baseline stability
5-6 am, 12 days
(P = 0.9185)
n = 7
0 2 4 6 8 10 12
0.0
0.5
1.0
1.5
Time (days)
I,nA
14th April 2016 | Dr. Saidhbhe O’Riordan | DCU CASi

10. Clinical O2 sensor
Translational research from benchtop to bedside
14th April 2016 | Dr. Saidhbhe O’Riordan | DCU CASi

11. Clinical O2
maynoothuniversity.ie14th April 2016 | Dr. Saidhbhe O’Riordan | DCU CASi

12. maynoothuniversity.ie
Clinical O2
Sensitivity
1.36 ± 0.045 nA/µM
R2 =0.99
n = 3
14th April 2016 | Dr. Saidhbhe O’Riordan | DCU CASi
0 5 10 15 20 25 30 35
0
100
200
300
400
500
25µM
50µM
75µM
100µM
125µM
Time, min
I,nA

13. Conclusion
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• Hydrogen peroxide
Characterised
Oxidative stress monitoring
Animal models
• Clinical O2
Rodent brain/periphery
Proof of concept
Human participants
Mr. Jack Kelly MB, FRCI, MD, FRCS (Plast) GUH
14th April 2016 | Dr. Saidhbhe O’Riordan | DCU CASi

14. Acknowledgements
• Prof. John Lowry
• Mr. Jack Kelly
• Neurochemistry Research Unit (MU)
• Dept. of Chemistry
• Health Research Board (O2)
• Wexford County Council (H2O2)