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Development and Preclinical Testing of Laser-Generated Shockwave Therapy for Infected Wounds

  • Author(s): Francis, Nathan Craig
  • Advisor(s): Grundfest, Warren S
  • et al.
Abstract

The goal of this thesis is to translate laser-generated shockwave (LGS) therapy from a bench- top, research system into a portable, clinical system for in vivo animal trials. Prior research along this topic was completed using a benchtop system, in a physical setup dissimilar to the clinical setup. So the technology required re-engineering in order to apply it to animal studies. This began with the construction of a portable LGS therapy system, mobile enough to transport from laboratory to clinical settings. Included in the portable system is a 2D scanning system to consistently treat wound areas of varying geometries with shockwaves of 3 mm diameter spot sizes. The shockwaves generated by the portable laser system were characterized, along with the varying shockwave-generating substrates possible for clinical application. A final material selection of black polyimide was chosen because of its complete absorption of laser light and its ability to conform to tight wound geometries.

Since shockwaves have never been demonstrated to delaminate biofilm from a tissue surface, a proof-of-concept study was completed successfully delaminating Staphylococcus epidermidis from wounded ex vivo pigskin. Through false-colored SEM imaging, biofilm area reduction between treated and non-treated samples were calculated. A 53% reduction in biofilm area and signifcant biofilm fragmentation was seen. An in vivo safety study was conducted next to observe potential physiological effects of LGS on healthy dermal tissue. Treated subjects were observed over a 3 day period, and no physiological or inflammatory effects were seen in the histological analysis. Finally, a pilot wound healing study was com- pleted on excisional wound healing model in rats, with S. epidermidis as the infectious agent, to measure the effect of LGS on wound healing area and rate compared to other treatments. After 9 days of wound healing, no treatment or controls showed a significant difference in wound healing rate or wound area. As a result, LGS also showed no deleterious effects on the tissue which would hinder wound healing. With these results, LGS therapy shows promise as an alternative infected wound treatment, and a system capable of completing thorough animal trials is available for future researchers.

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