Dissertation
Multiscale modeling of the skin’s biomechanics and aging
University of Iowa
Doctor of Philosophy (PhD), University of Iowa
Spring 2024
DOI: 10.25820/etd.007438
Abstract
Skin is a complex multilayered tissue that regulates temperature and hydration, provides sensory information to the nervous system, and protects against chemical, biological, and physical assaults from the environment. It also must be distensible to accommodate body movement and tough enough to withstand physical forces that could lead to tissue damage. It is increasingly clear that the local mechanical environment within a tissue provides important cues that regulate normal tissue function. These cues are highly dependent on the local composition and organization of the extracellular matrix, as well as mechanical forces transmitted across spatial scales of the tissue. The effects of disease, aging, injury, and repair of the skin all depend heavily on how macroscopic tissue-level forces distribute down to the microscale level of cells and matrix proteins. Thus, to understand dynamic changes in skin function, including those associated with aging and injury, it is critical that one takes a multiscale perspective.
However, investigating the multiscale structure-function relationships of skin faces challenges due to experimental limitations and the difficulty in replicating microstructural kinematics using standard computational modeling techniques. To better understand the skin’s biomechanics, we constructed image based multiscale mechanical models (MSM) of mouse skin and represented the collagenous dermis with experimental images of dermal microstructure acquired during mechanical testing. Three models that spanned the cases of highly aligned, moderately aligned, and nearly random fiber networks were examined and compared to the data acquired from uniaxially stretched skin. We also investigated alterations in the skin with aging by simulating increased nonenzymatic crosslinking with discrete fiber networks, representing changes in collagen fiber properties and fiber-fiber connectivity (i.e., network fragmentation). Furthermore, we analyzed the influence of increased collagen fragmentation on the mechanical behavior and failure properties of skin using notched multiscale models loaded in tension. These findings contribute to a better understanding of the dermal microstructure with changes in alignment and age dependent alterations with nonenzymatic crosslinking.
Details
- Title: Subtitle
- Multiscale modeling of the skin’s biomechanics and aging
- Creators
- Nathaniel James Witt
- Contributors
- Edward Sander (Advisor)Kyle Quinn (Committee Member)Suresh Raghavan (Committee Member)Jacob Herrmann (Committee Member)
- Resource Type
- Dissertation
- Degree Awarded
- Doctor of Philosophy (PhD), University of Iowa
- Degree in
- Biomedical Engineering
- Date degree season
- Spring 2024
- DOI
- 10.25820/etd.007438
- Publisher
- University of Iowa
- Number of pages
- xii, 90 pages
- Copyright
- Copyright 2024 Nathaniel James Witt
- Language
- English
- Date submitted
- 04/23/2024
- Description illustrations
- Illustrations, tables, graphs, charts
- Description bibliographic
- Includes bibliographical references (pages 75-85).
- Public Abstract (ETD)
As the population ages and obesity rates rise, the incidence of skin injuries and hospitalizations is projected to escalate. By 2024, the financial burden associated solely with treating chronic wounds is estimated to exceed $22 billion. With advancing age, the skin undergoes notable changes, leading to increased susceptibility to wrinkles, fragility, and compromised wound healing. These alterations stem from shifts in the underlying structure of the skin, particularly within the dermal layer. Reductions in hydrating proteins and disruptions in the collagen network, responsible for skin strength, are key factors in this process. However, comprehending the precise implications of changes in the skin’s mechanics and health poses a challenge. While mechanical forces exerted on the skin influence cellular behavior and repair mechanisms, the intricacies of these interactions remain incompletely understood. This is particularly true of the structure-function relationships deriving from the dermal microstructure and their contributions to the biomechanical properties, failure characteristics, and changes with aging of the skin. The studies contained herein aim to investigate these underlying mechanisms via computational models that allow for detailed analysis at the tissue and microstructural levels. Ultimately, this may yield advancements with potential implications for enhancing wound healing and promoting overall skin health in the future.
- Academic Unit
- Roy J. Carver Department of Biomedical Engineering; Craniofacial Anomalies Research Center
- Record Identifier
- 9984647646102771
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