Exhaled breath condensate based breath analyser
File(s)
Author(s)
Chen, Yu-Chih
Type
Thesis
Abstract
Exhaled breath condensate (EBC) based breath analysis has gained significant interest in
pulmonary disease diagnostics over the past few years due to the non-invasiveness and
simplicity of the technique.
Most approaches to date have separated EBC collection from the subsequent lab-based
analysis, more notably, integrated EBC collector and analyser do not exist. Under current
suggested protocol EBC samples for hydrogen peroxide analysis needs freezing at -70 C
immediately after collection but still exhibit instabilities in concentration.
To address those difficulties and to provide easy-to-use devices for patients, we have
proposed a portable integrated EBC analyser, which gives measurement results within 3
minutes. The device incorporates Peltier cooling for sample collection; electronics control
system and a disposable chemically modified amperometric sensor.
Cooling system and device architecture were designed based on thermofluidic analysis of
Falkner-Skan solution. Theoretical modelling and experimental evidence suggest that
previously reported large variations between analyte concentrations arise from poor control of
the condensation process. Fundamental studies suggest higher condensation temperature
favours more concentrated analyte collection, relieving the burden on electrochemical sensor
limit of detection (LOD).
Low hydrogen peroxide in EBC presents another challenge. We have developed a modified
Prussian blue (PB) sensor, by blending PB in conducting polymer matrix to increase PB
density on electrode as well as cross linking matrix to improve the mechanical properties and
enhance processability. Full mechanistic investigation using rotation disk electrode and
chronoamperometry experiments reveal the kinetics of the sensor and informed subsequent
development. The sensor has been demonstrated to measure hydrogen peroxide in EBC.
pulmonary disease diagnostics over the past few years due to the non-invasiveness and
simplicity of the technique.
Most approaches to date have separated EBC collection from the subsequent lab-based
analysis, more notably, integrated EBC collector and analyser do not exist. Under current
suggested protocol EBC samples for hydrogen peroxide analysis needs freezing at -70 C
immediately after collection but still exhibit instabilities in concentration.
To address those difficulties and to provide easy-to-use devices for patients, we have
proposed a portable integrated EBC analyser, which gives measurement results within 3
minutes. The device incorporates Peltier cooling for sample collection; electronics control
system and a disposable chemically modified amperometric sensor.
Cooling system and device architecture were designed based on thermofluidic analysis of
Falkner-Skan solution. Theoretical modelling and experimental evidence suggest that
previously reported large variations between analyte concentrations arise from poor control of
the condensation process. Fundamental studies suggest higher condensation temperature
favours more concentrated analyte collection, relieving the burden on electrochemical sensor
limit of detection (LOD).
Low hydrogen peroxide in EBC presents another challenge. We have developed a modified
Prussian blue (PB) sensor, by blending PB in conducting polymer matrix to increase PB
density on electrode as well as cross linking matrix to improve the mechanical properties and
enhance processability. Full mechanistic investigation using rotation disk electrode and
chronoamperometry experiments reveal the kinetics of the sensor and informed subsequent
development. The sensor has been demonstrated to measure hydrogen peroxide in EBC.
Version
Open Access
Date Issued
2020-08
Date Awarded
2021-04
Copyright Statement
Creative Commons Attribution NonCommercial ShareAlike Licence
Advisor
O'Hare, Danny
Publisher Department
Department of Bioengineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)