Hair cells are a class of mechanosensory receptor cells in all vertebrates, which are used to detect sound, head movement, vibration, and gravity. The first step in the process converting the mechanical stimulus to a nerve signal is the deflection of the microscopic bundle, called a ciliary bundle, that is a tuft of hairlike processes on the top of the cell. This project is a collaborative bioengineering effort between a neurobiologist and a bioengineer, using a novel methodology to explore the micromechanics of these bundles. Microscopic anatomical techniques are used to quantify the detailed structures of the ciliary bundles, and these data will be used in a computational model incorporating the contribution of different structural elements to bundle mechanics, and to predict the performance of bundles having different shapes and sizes. A novel fiber-optics system technology is being developed to measure bundle stiffness by direct experiments on an isolated preparation of tissue, to test the model predictions. These studies will provide important fundamental and novel information on mechanosensory mechanisms at the subcellular level, with impact on auditory and other mechanosensory systems, and the technology developed may have important applications in micromechanics in bioengineering and biomedical applications, and in industry.
