Shown above is a digital image of two orthogonal lateral views of a bovine articular cartilage explant tested in unconfined compression. Mirrors are used to simultaneously project the two orthogonal views to a digital camera. Post-processing of the images in MATLAB allows the calculation of Poisson's ratios in the two orthogonal directions to aid in determining anisotropic material properties.
Introduction
The Cal Poly Cartilage Biomechanics Group is a team of engineering students and professors who share the interest of studying the biomechanics of the human body using state-of-the-art engineering analysis.
Biomechanical engineering can be described as reverse engineering, in which the design principles of a system are discovered after studying its structure and function. This approach is the opposite of traditional design analysis, where objectives and constraints are identified, materials are chosen, and analysis leads to the creation of a component, system, or process. In the study of biomechanics, the design (i.e. the human body or its parts) and its component materials (i.e. tissues) are given, and experimental and theoretical studies are performed in order to discover the design principles.
In order to improve or repair certain features of the human body, we must first understand the properties of the design materials. Our work involves modeling the biomechanical properties of articular cartilage tissue, especially during in vitro (i.e. outside the body) growth and remodeling experiments with tissue explants subjected to different types of mechanical and biochemical stimulation.
Accurate modeling of tissue biomechanics at the organ, tissue, and cellular levels is a challenging and increasingly complex field of study. Despite the obstacles, the Cal Poly Cartilage Biomechanics Group aims to aid in the development of improved diagnostic, preventative, and therapeutic methods to reduce the incidence of articular cartilage tissue injury and disease. Important secondary aims of our research are to enhance health related research in our predominantly undergraduate engineering program at Cal Poly San Luis Obispo, and to engage undergraduates in biomedical research to help prepare them for careers in biomedical engineering.
Shown above are proteoglycan (PG) and collagen (COL) volume fraction contours predicted by our cartilage growth finite element model for in vitro growth in a steady state permeation bioreactor. This configuration corresponds to release from the bioreactor chamber and illustrates the non-uniform geometry that results from growth. The average dimension of the elements are 25.33 × 63.85 μm. The curvature deformation is scaled by a factor of 5.
© 2008 Stephen M. Klisch | Mechanical Engineering