A Biophotonics Platform for Mechanotransduction and Metabolic Microscopy (M3) Project Summary: (30 lines) Mechanotransduction has emerged as one of the main regulators of biological function. While the downstream effects of cellular mechanotransduction have been widely studied, the interplay between cellular mechanotransduction and metabolism remains relatively unexplored. This proposal represents a multi-disciplinary collaboration between specialists in mechanobiology, laser-tissue interactions, and advanced fluorescence microscopy methods to develop a unique biophotonics technology platform that enables the precise application of impulsive force to 2-D cell cultures, 3-D tissue cultures, and live animal models to dynamically measure cellular mechanosensitivity and cellular mechanosignaling and correlate these with metabolic state, membrane fluidity, messenger RNA (mRNA) expression, as well as cell/matrix composition, morphology, organization, and stiffness. This will be achieved through a unique integration pulsed laser microbeam irradiation used for cell/tissue stimulation with laser scanning confocal (LSCM), multi-photon (MPM), fluorescence lifetime imaging (FLIM) microscopy, and multi- spectral imaging modalities. We will verify and demonstrate the capabilities of this platform in a variety of 2-D cell culture and 3-D tissue culture systems of varying complexity and material composition and stiffness. The proposed technology development will enable a unique capability to measure and examine the dynamic cellular interplay of sensitivity to mechanical cues, mechanosignalling, and other biological system characteristics including cellular metabolism, mRNA expression, and extracellular matrix remodeling. The proposed technology platform has broad applications for the study of normal tissue development and disease and for high-throughput drug screening.