Jennifer Triana

Document Type

Honors Thesis

Major

Biomedical Engineering

Advisor(s)

David Neivandt

Committee Members

Ian Dickey, Walter Golet, Melissa Ladenheim, Anne Lichtenwalner

Graduation Year

May 2021

Publication Date

2025

Abstract

Studies such as population and migration analyses of fish are often heavily reliant upon the retention of external fish tags. However, external fish tags are prone to shedding due to a range of factors including weak attachment, the forces experienced during swimming, and interactions with the environment. In addition, it has been observed that wound healing around the site of implantation is often poor. The present work aimed to develop a fish tag that would promote dermal and subcutaneous tissue ingrowth, thereby promoting wound healing and more secure tag attachment. Soft tissue ingrowth and attachment to porous foam metal implants, including in transcutaneous applications, has been successful in a variety of mammalian models. The present work therefore extended these investigations to a piscine model. Two fish tags were designed with porous foam metal elements in the dermal and subcutaneous locations. The first tag was modeled after a conventional nylon dart tag. The second tag was designed as a reenvisioned pop-up satellite tag. Electron beam melting additive manufacturing was employed to print the tags in porous foam titanium. Twelve adult Atlantic salmon were employed as an animal model. A single nylon dart tag was implanted on the left side, and a single porous foam metal dart tag was implanted on the right side of the fish. The fish were harvested at 2, 4, and 9 weeks post-tagging. Tissue samples were taken from the nylon and the porous foam metal tag sites, as well as from a control site away from either tag to represent normal tissue. The tissue samples were stained and analyzed optically to determine the percentage of new fibrous tissue, the presence of which would provide evidence of tissue remodeling and healing. Initial assessment indicated greater tissue remodeling surrounding the porous foam metal implants versus the nylon implants at the 2 and 4 week time points. Statistical analysis however indicated the differences were not significant, a fact potentially attributable to the small size of the study and unbalanced data sets. Nonetheless, all porous foam metal implants were retained in the fish, whereas as one nylon implant was shed. It was concluded therefore that porous foam metal external fish tags may well have utility relative to conventional tags, and that follow on studies should be performed to determine histologically the extent of tissue ingrowth, and to measure the force required to pull out both conventional and porous foam metal tags

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