Understanding compression-induced damage in cartilage using high resolution optical elastography
Abstract
Understanding compression-induced damage in cartilage using high resolution optical elastographyUnderstanding the mechanical behavior of biological materials is immensely complex due to the heterogeneity of the architecture at both the nano- and microscale. For example, in a tissue slice, cells are connected by the extracellular matrix (ECM). While it is clear that the ECM and the cells have different stiffness values, recent results show an inter-dependence between the two systems. More importantly, the time-dependent cell viability may induce mechanical behaviorchange in the tissues.The nature of this dependence is of particular importance in tissue where the structure and mechanical properties directly determine the physiological behavior, and damage in one structure can induce a behavioral change. Understanding the cause and effect has the potential to enable improved preventative measures to be developed or to inform treatment methods. Therefore,performing measurements with live tissue is critically important in order to draw accurate conclusions.Current methods for characterizing the mechanical behavior of materials attempt to balance spatial resolution with material complexity, forcing researchers to choose between either measuring individual cells (high resolution, but low sample complexity) or complete tissue (low resolution, but high complexity). Both methods result in key information being left out of theanalysis. Moreover, the majority of the research trying to understand cartilage damage has focused on one of two areas: sports injuries or age-related degradation. Neither of these is similar to those experienced by military personnel. Sports-related injuries frequently arise from a single, traumatic event of high impact, as opposed to repetitive low to moderate impact. However, the age group is similar to military personnel. In contrast, age-related degradation can be viewed as similar because the wear is from repetitive motion and moderate impact. Unfortunately, the agegroup is significantly older, and therefore, in most cases, additional complications have also begun to play a role.We hypothesize that the mechanical behavior of soft biomaterials, and changes in the behavior, are due to the microstructure evolution within the biomaterials. While this behavior occurs naturally over time, the process can also be accelerated by environmental factors. The proposed multi-faceted research effort leverages advances in 3D printing of biomimetic sampleswith advances in mechanical profiling to develop a comprehensive model of tissue degradationdue to repetitive compressive stress and validate it experimentally.Using an optical polarimetric elastography characterization instrument pioneered by the PI, aseries of 3D printed biomimetic samples and tissue (cartilage and skeletal muscle) samples will be characterized before and after damage. The 3D-architected elastomer lattices will be designedto mimic different structures with different failure mechanisms. This series of measurements isenabled by the micron-scale resolution of the optical polarimetric system.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 03, 2017
- Source ID
- N000141712270
Entities
People
- Andrea Armani
Organizations
- Office of Naval Research
- United States Navy
- University of Southern California