Publication Date


Document Type


Committee Members

Greg Boivin (Committee Member), Robert Goldenberg (Advisor), Larry Ream (Committee Member)

Degree Name

Master of Science (MS)


Polyvinylidene fluoride (PVDF) film, a biomaterial that is an integral part of a Totally Implantable Sustainable Hearing Aide (TISHA) device, was examined to determine its biocompatibility within the murine cochlea. The biofilm was implanted in the ear using a round window cochleostomy in 7-9 week old male C57BL/6 mice. Three test groups containing seven mice each were implanted with PVDF film. Each mouse received a sham surgery on the non-implanted cochlea. Three test groups were examined at 48 hours, 3 weeks, and 3 months. At the end of this time the mouse was euthanized, the tissue containing the cochlea was extracted, decalcified in cal-rite solution, processed through a gradient of alcohols and xylene and embedded in paraffin. Slides were made and stained with Hemotoxylin and Eosin.The degree of the Foreign Body Reaction (FBR) in the cochlea with the implanted biofilm was determined quantitatively and qualitatively using nonparametric and parametric tests. We found that quantitatively the amount of erythrocytes significantly decreased between the 48 hour and 3 week survival length groups (1-way ANOVA, P-value=.020). The amount of neutrophils significantly decreased between the 48 hour and 3 week (1-way ANOVA, P-value=0.22) and 48 hour and 3 month survival length groups (1-way ANOVA, P-value=0.28). Membrane formation around the implant and presence of foreign body giant cells (FGBCs) and fibrocytes were evident in the chronically implanted animals. Damage to inner and outer hair cells of the Organ of Corti was observed in both implanted and control cochlea. Angiogenesis, a normal phase of the healing process, was significant only in the 3 week survival group (Fisher's exact test, P-value=.0002). Animals were assigned individual scores that were related to a certain intensity level of the FBR. There was a significant increase in the average score of the FBR between the 48 hour and 3 week survival length group (Kruskal-Wallis test, P-value=.030). The majority of animals were assigned the lowest intensity level, very mild, while 3 animals received a mild intensity rating. We determined that PVDF film was biocompatible based on the observation that acute responses of the FBR decreased after the initial time of implantation, chronic response of the FBR did not progress in intensity after the 3 week time point, the average rank of the FBR was the lowest score on our intensity scale, and the components of the FBR did not spread from the site of implantation into surrounding areas of the cochlea. PVDF film did not interrupt the healing process of the host such as the clotting mechanism or become extruded from the cochlea.

Page Count


Department or Program

Department of Neuroscience, Cell Biology & Physiology

Year Degree Awarded


Included in

Anatomy Commons