My interests broadly span experimental studies of protein dynamics and photophysics in vitro and in vivo, and development of optical tools to explore biological function. Over the past several years we developed innovative new methodology integrating spectroscopy with flow cytometry. Although we continue to deepen our understanding of molecular dynamics with femtosecond and longer-timescale spectroscopy in vitro, we have broken new ground by developing microfluidics-based single-cell spectroscopy techniques to characterize photophysics in vivo on 105–member libraries of fluorescent proteins. We are performing selections to isolate clones with new properties and discover structure-dynamics relationships that would not be apparent from conventional biophysical studies focusing on a small number of variants. We have also developed a microfluidic method to initiate and monitor the dynamics of ratiometric biosensors in single cells within a population, and the capability to sort libraries based on the magnitude or kinetics of the sensor response. These and other novel technologies developed in my lab are integral to our directed evolution strategies for creating new biophotonic functionalities. The payoffs we envision range from discovery of new molecular dynamics underlying the unique photophysical properties of chromoproteins to biological applications benefitting from the improved visualization and control of cellular events.