Thesis
Development of a disposable sensor system for monitoring the pH of wounds and wound dressings
- Creator
- Rights statement
- Awarding institution
- University of Strathclyde
- Date of award
- 2012
- Thesis identifier
- T13305
- Qualification Level
- Qualification Name
- Department, School or Faculty
- Abstract
- The pH of a wound can affect many different phases of the healing process such as oxygen levels, cell proliferation, protease enzyme activity and bacterial growth. If the pH level of a wound can be effectively monitored then it can act as a biological marker to aid in diagnostics and in establishing the optimum conditions for healing. However without an easy to use pH sensor for nurses and carers, this potentially important near-patient diagnostic parameter, will not enter clinical diagnostics. The standard glass pH electrode is still the only effective way to measure the pH of a wound. They are expensive and difficult to sterilise. The pH electrode has not been successfully adapted into smaller and alternate packaging because the membrane that forms the selective part of the electrode, being made of silicon glass, is fragile, thus limiting manufcture, sterilisation and practical application. This thesis describes two defined areas of work. The first area reported details the development of a disposable hand-held measurement system for measuring wound pH. Four screen printed solid state sensor types are studied and evaluated. Three of the sensors are based on conducting polymers (Polypyrrole doped with C1¯ or PTS¯ ions and PEDOT) with ion-selective membranes. The fourth sensor tested is the screen printed carbon electrode with an ion-selective membrane. The best performing sensor was the carbon coated with an ion-selective membrane which was operational in the pH range 3.5-10. The superior performance of the carbon substrate was investigated and attributed to the partial dissolving of the screen printed carbon layer during membrane deposition, enabling good sensor adhesion and stability between the mebrane and conducting contact. The second area for invetigation that is reported here describes the use of the developed pH measurement system to observe the influence on pH of a number of wound dressings (Activon Tulle (Advancis Medical), Aquacel(Convatec), Tegaderm Matrix (3M) and Promogran(Systagenics)) in real time after application to a wound bed model. The wound dressings were first tested in a non-buffered (for pH) solution to observe the pH change. It was found that the dressings all had low pH values of below pH4 in this environment. The second experiment used horse serum as a woiund exudate substitute to monitor the real time change in pH after application of wound dressing as it would mimic the buffering capacity of real wound exudate. The results showed that the Tegaderm dressing had the strongest acid concentration but that all the wound dressings would influence local pH in a wound to some extent. The variation in the pH measured on the wound bed model with the different dressings highlights the need to gain a further understanding of the role of pH, dressing influence on pH and the optimum pH conditions for wound healing.
- Advisor / supervisor
- Connolly, Patricia
- Resource Type
- Note
- Previously held under moratorium from 8th January 2013 until 8th January 2017.
- DOI
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