During early stages of injury, degeneration, and disease, soft tissues often exhibit disrupted or abnormal tissue microstructure, or extracellular matrix. Currently, direct detection of these changes requires invasive optical imaging methods not suitable for routine screenings. Alternatively, multi-scale modeling of mechanical behavior could leverage structure-function relationships to “see” tissue microstructure, with lower resolution, non-invasive imaging modalities (e.g., MRI, ultrasound). However, accurate material modeling of soft tissues has been challenging, as strain heterogeneity invalidates assumptions required for standard modeling methods. In contrast, full-field (i.e., image-based) methods for material characterization make strain heterogeneity an asset; the multiple modes and states of strain present in a single heterogeneous deformation are collectively used to better inform models of material behavior. In this talk, I will present evidence that specific microstructural features can be discerned using mesoscale measures of mechanical function alone. Specifically, I will describe my work using full-volume deformation fields and inverse methods to construct constitutive models for ligament tissues. I will also discuss ongoing work to develop damage models for soft tissues and the application of my methods to study how extracellular matrix composition and organization affect injury risk. Finally, I will present my roadmap for integration of these ideas to develop mechanics-based technology for non-invasive detection of tissue microdamage and microstructural abnormalities.
About the Speaker
Callan Luetkemeyer is a Schmidt Science Fellow in the Department of Mechanical Engineering at the University of Colorado Boulder, where she collaborates with Sarah Calve, Corey Neu, and Virginia Ferguson. She earned a bachelor’s degree in Biomedical Engineering in 2014 from St. Louis University and a Master’s degree and Ph.D. in Mechanical Engineering in 2020 from the University of Michigan, where she was advised by Ellen Arruda. For her work on image-based material modeling of soft tissues, Callan received the McIvor Award for Excellence in Applied Mechanics Research from the University of Michigan College of Engineering, the Savio Woo Young Researcher Award from the International Symposium on Ligaments and Tendons, and the Schmidt Science Fellowship from Schmidt Futures, which has allowed her to pursue her own research vision as a postdoctoral fellow.