A Study into the Utility of Impedance Spectroscopy to Give Predictive Information About Skin Breakdown

  • Emily Owen

Student thesis: Doctoral ThesisPhD


This thesis explores the utility of Electrochemical Impedance Spectroscopy (EIS) to provide predictive information about skin breakdown, focusing on early-stage pressure ulcers and Incontinence Associated Dermatitis (IAD). Principal skin models used in this study included ex vivo porcine skin and in vivo human skin.
The third chapter involved developing a protocol to measure skin barrier function, using EIS. The impedance data was fitted to an R1(R2Q) equivalent circuit model, where changes in resistance (R2) related to stratum corneum integrity, in terms of thickness and hydration status. The technique was found to be equally sensitive, if not more, as standard measures of skin barrier function, including TEWL and stratum corneum moisture.
The fourth chapter involved modelling early-stage pressure ulcer formation via changes in stratum corneum resistance, using the established EIS technique. Evidence suggested that the two suspected mechanisms of pressure injury (physical deformation and ischaemia-reperfusion injury) significantly contribute to skin damage. Given that the mechanical loading applied to human participants was not sufficient to disrupt the skin barrier in some individuals, this shows that EIS is a useful tool to monitor an individual’s tissue tolerance and implement personalised pressure ulcer management strategies.
The fifth chapter explored IAD, in terms of the role of enzyme urease in converting urea into ammonia. The accumulation of ammonia was found to cause a significant reduction in skin resistance which was specific to ammonia, as opposed to simply the high pH. Furthermore, the high pH was linked with increased activity of faecal enzyme trypsin and opportunistic pathogens, Candida albicans and Staphylococcus aureus, in terms of enhanced skin damage. Finally, two urease inhibitors, acetohydroxamic acid (AHA) and Nasturtium officinale (N. officinale), were shown to reduce urease-mediated skin damage. This suggests that urease inhibition could be a future therapeutic strategy to improve management of IAD.
Date of Award24 Apr 2024
Original languageEnglish
Awarding Institution
  • University of Bath
SponsorsConvatec Ltd.
SupervisorToby Jenkins (Supervisor) & Frank Marken (Supervisor)


  • Impedance spectroscopy
  • Skin barrier function
  • Pressure ulcer
  • Incontinence associated dermatitis
  • Urease

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