Title

In vivo studies and physical models of skin wound healing enhanced with rectangular pulse electrical current stimulation

Date of Award

1994

Availability

Article

Degree Name

Doctor of Philosophy (Ph.D.)

First Committee Member

Peter P. Tarjan, Committee Chair

Abstract

Rectangular pulse electrical current stimulation (RPECS) has been successfully used to enhance skin wound healing. This dissertation is an experimental and analytical investigation of skin regeneration with RPECS at animal, tissue as well as cellular levels, from the view points of engineering and physics. Altogether four key topic areas have been addressed. Based on the experimental results, physical models were proposed.A new conforming electrode was developed and evaluated in experiments with 27 domestic pigs. Better epithelialization results were obtained with RPECS than with any dressing before. Reepithelialization rate vs electrical polarity, duration of the treatment per day, and wound locations were evaluated.In an analytical study at the cellular level, some physical models were developed to quantitatively describe the electrical stimulation of skin cells in terms of electrical voltage and current in the time and the frequency domains. In the time domain, a physical model was proposed to yield a suitable range of externally imposed current for skin wound healing enhanced with RPECS. The model was developed with the help of Cole's formula and published data. The physical models were supported by our in vivo and in vitro experiments. In the frequency domain, RPECS was analyzed using the Fourier transform and found that the RPECS we used could not penetrate the skin cells directly, but polarize or depolarize the cell membrane.In an in vitro experiment on tissue, the conductivities of pig skin and subcutaneous fat were examined. The conductivities were found to be independent of the current density and pulse rate in this experiment. The conductivities of pig skin dermis and subcutaneous fat were both found to be anisotropic. The conductivity data can be used in the physical models we developed.In a further in vivo experiment, 3-D distributions of exogenous electrical fields in pig skin were measured during RPECS. The measured perpendicular fields in the dermis under the stimulating electrodes, were confirmed to be in agreement with the calculated field, consistent with our physical assumption.

Keywords

Health Sciences, Rehabilitation and Therapy; Engineering, Biomedical

Link to Full Text

http://access.library.miami.edu/login?url=http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:9500229