Fluorescein Derivative Monomer for the Production of Fluorescent Latex Particles

Abstract The use of fluorescent latex particles (FLP) as a tool for microscopy imaging or flux cytometry is an excellent choice for diagnosis, research, and development. They are suitable for complex formation with several biological molecules and macromolecules. A simple and cost‐effective method is here proposed to produce FLP. To this effect, the synthesis of a fluorescent monomer, capable of being copolymerized with vinyl monomers, is achieved by a reaction between fluorescein and glycidyl methacrylate, and monitored by UV–vis, IR, NMR, and Fluorescence spectrometry. The synthesis of fluorescent particles is carried out by emulsion copolymerization of styrene, methacrylic acid, and the fluorescent monomer. Latexes are characterized by measuring styrene/methacrylic acid conversion, average particle diameter, fluorescence, surface charge, and group density. Conversion reaches ≈90%, and negatively charged particles of 130–260 nm are obtained, which proved to have high fluorescence with an emission maximum of 511 nm. Cell fluorescent staining is carried out using the obtained particles. Observation of the FLP‐treated cells by confocal microscopy exhibited intense fluorescence within all the internal media, with a fluorescein‐like emission pattern. The production of stable fluorescent particles, with controlled size and high fluorescein incorporation, capable of interacting with proteins and cells efficiently, is confirmed.