Summary This SBIR Phase II project is focused on the design refinement, development, and testing of a ground-breaking multidimensional multifunctional quantitative optical microscopy modular system suitable for live whole cell studies. The proposed Light Engineering modular system addresses the critical need for flexible imaging techniques to image live whole cells with low photodamage and phototoxicity while providing high spatial and temporal resolution as well as a large volumetric field of view. Despite extraordinary advances in optical microscopy, the availability of state-of-the-art commercial solutions has been slow to market, lacking in flexibility and ease of access. The modular instrument is based on an integrated design of the illumination, 3D optical response, data collection, and reconstruction algorithms for fluorescence imaging. Specifically, engineered 3D light excitation limits the background noise while reducing photodamage and phototoxicity. The engineered 3D point spread functions enable multiplex functionality including an extended depth of field imaging, high-sensitivity 3D localization of single-molecules or cellular heterogeneities, multi-color, and 3D imaging. As a result, the target performance outperforms the state of the art in terms of spatial/temporal resolution, signal-to-noise ratio, field of view, single-molecule localization precision, and ease of use. This project is targeted towards commercialization of a cost-effective modular solution that can be easily integrated with existing scientific microscopes. The commercial-ready prototype, will include a small footprint architecture, a set of novel optical phase masks for point spread function engineering and excitation shaping, a robust optomechanical design, and real-time experiment control software. Tests of the instrument in significant biomedical problems at partners? labs will validate end-user acceptance and provide valuable feedback towards commercialization. The implications in biomedical imaging are far-reaching. For instance, the instrument would benefit the study of oncogenesis, owing to its degree of molecular sensitivity for detecting the spatial localization of receptors and other signaling molecules within the tumor/extracellular matrix. It would also empower the study of degenerative diseases where the instrument can help reveal their molecular origin and develop novel therapeutic strategies. The new imaging capabilities could also advance stem cell, cancer and brain research. Double Helix Optics is a startup company with exclusive licensing rights to the Light Engineering technology from the University of Colorado, as well as the novel Tetrapod and Multicolor PSF localization developments from Stanford University. The company, headquartered in the BioFrontiers Institute in Boulder, is optimally positioned to successfully bring this product to market.