Elucidating the Stiffness of Extra-Cellular Matrix Fibers with High Speed Microscopy

Research over the past two decades has shown that cellular behavior is heavily influenced by the mechanical properties of the surrounding microenvironment. Microenvironment constituents such as extra-cellular matrix (ECM) fibers have been implicated as playing an important role in diseases such as cancer and fibrosis. However, quantifying ECM stiffness on a cellular scale is non-trivial and consequentially it is difficult to quantify its influence on cellular behavior and disease. In response to this problem, our lab is developing a method to quantify the mechanical properties of individual ECM fibers using a high-speed reflection confocal microscope with Space Time Image Correlation Spectroscopy (STICS). The confocal microscope, using a modified Olympus DSU spinning slit-disk confocal unit, will acquire image data at a high rate: close to 100 frames per second. In comparison, normal confocal systems image up to 60 frames per second. The images will then be analyzed using the STICS method through which the elastic storage modulus of individual fibers can be estimated. We have successfully built a prototype high-speed confocal microscope and are currently building the next generation. This tool will greatly inform future studies of the interplay between cellular behavior and ECM mechanics by quantifying how mechanics influence phenotype on the cellular scale.