Among a stratum of engineering solutions that address global health issues, instrumentation and devices that enable early disease diagnoses are critical. In the case of ex-vivo, or in vitro, diagnostic systems, optic and photonic-based devices are quite useful. The measurement of light scatter and fluorescence in particular can indicate cellular shape, size, genetic expression, protein movement, and many other types of molecular phenomena. Fluorescence microscopy tools enable these measurements as do flow cytometers. Flow cytometers, like microscopes, capture fluorescence and autofluorescence when emitted from cells, so that intracellular molecular events can be studied. Moreover flow cytometers permit high-throughput measurements by continuously moving or ''flowing'' the cells while measuring the fluorescence output. Faculty in the CHME department are designing and improving cytometry-based instrumentation and assays to study fluorescence decay kinetics and improve the ways in which light is used as an indicator of cellular heterogeneity.