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Dissertation
Measurement and analysis of electrical impedance in simplified dermal surrogate model (SDSM) with ultrasound and chemical stimuli
Doctor of Philosophy (Ph.D.), Drexel University
Nov 1999
DOI:
https://doi.org/10.17918/00000616
Abstract
The goal of this study had been to develop an electrical impedance spectroscopy (EIS) technique and investigate its applicability when used in a simplified dermal surrogate model (SDSM). Such a model is highly desirable to minimize animal experiment. Two types of agents, aggressive chemical stimulus agent (sodium lauryl sulfate (SLS)) and beneficial stimulus agent (ultrasound), were used. The study of ultrasound stimulus test was prompted by our previous findings which showed that appropriate ultrasound exposure could result in increased rate of wound healing. The healing process was also reflected by measurable changes in the electrical impedance of intact skin. The project required development of the electrical impedance analyzer and skin substitute. The model consisted of a computer, function generator, instrumentation amplifier, and multifunction data acquisition board. The instrumentation was controlled and coordinated using virtual instrumentation (VI) implemented in LabViewTM. The dermal surrogate model (SDSM) was fabricated using a biobarrier material (gelatin) with erythrocytes added to allow evaluation of membrane integrity. Studies were performed using ultrasound energy at several frequencies (0.75 MHz, 1 MHz, and 2 MHz) and energy levels, and with 0.5% sodium lauryl sulfate (SLS). The electrical impedance was measured at three frequencies, 50, 100, and 500 Hz, and used to calculate the (DC) resistance, reactance, and phase change. The measured data resistance, reactance, and phase change were used to solve an electrical equivalent skin model in order to obtain the values of membrane capacitance (MC), intracellular resistance (ICL), and extracellular resistance (XCL). The results of this experiment suggested that a simplified dermal surrogate model (SDSM) is suitable for chemical testing. Changes were determined in the model parameters reflecting penetration of a protein matrix, alternation of membrane integrity, and possible effects on organelle function. Also, it was found that the electrical impedance spectroscopy method holds promise for monitoring the interaction between therapeutic ultrasound levels and skin.
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Details
- Title
- Measurement and analysis of electrical impedance in simplified dermal surrogate model (SDSM) with ultrasound and chemical stimuli
- Creators
- Min-Chih Chou
- Contributors
- Stephen E. Dubin (Advisor)Peter Andreas Lewin (Advisor)
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- xii, 146 pages
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- School of Biomedical Engineering, Science, and Health Systems (1997-2026); Drexel University
- Other Identifier
- 991014970315104721