There is a strong interest in nanoparticles (NPs) in bio-applications, and in particular cerium oxide (CeO2) ones due to their unusual redox and optical properties, stability and biocompatibility. Cerium is a rare earth element and is naturally abundant in the Earth's crust, e.g., 66.5 mg/kg similar to copper and zinc. Unlike most rare earth metals, cerium can exist in both +3 (fully reduced) and +4 (fully oxidized) states. There is a mix of both valence states in the CeO2 NPs form which exhibits oxygen vacancies or defects in the lattice structure. Changes in redox state and oxygen vacancies impact CeO 2 NPs physical and chemical properties such as intrinsic photoluminescence (multi colored emission) and biological activity (interaction with free radicals). The photophysics of such CeO2 NPs strongly depends upon their growth, heterogeneities and defects. This study aims to develop CeO 2 NPs synthesis control the size and luminescence properties using to microfluidic techniques. Real time monitoring using Fluorescence-Lifetime Imaging Microscopy will provide an in-depth understanding of single NPs growth.