Synthesis of uniform, fluorescent poly(glycidyl methacrylate) based particles and their characterization by confocal laser scanning microscopy

Abstract

Uniform poly(glycidyl methacrylate) (poly(GMA)) particles with different size and surface properties were obtained by dispersion polymerization formulations including different initiator and stabilizer types. The particle size was correlated with the half-life of the initiator. The use of poly(acrylic acid) (PAA) as a novel steric stabilizer in the dispersion polymerization of GMA resulted in the synthesis of smaller particles with higher surface charge density with respect to those in the literature. As a new initiator–stabilizer system for GMA, 4,4′-azobis(4-cyanovaleric acid)–poly(acrylic acid) provided the synthesis of bifunctional uniform latex particles carrying epoxide and carboxyl groups. The reactive character of poly(GMA) particles allowed the preparation of their primary amine carrying form. The fluorescent form of the amine carrying poly(GMA) based latex particles was first obtained by labeling with FITC and characterized by confocal laser scanning microscopy (CLSM). A CLSM method was developed to determine the amine group distribution in the particles based on the fluorescent intensity profile. A core part with low primary amine content was observed in the particle interior while the amine group concentration was high on the shell part located on the particle surface. The photobleaching time of poly(GMA) based particles was found to be two-fold longer than the highest value reported for the uniform particles. Low photobleaching rate is extremely important for the CLSM applications of uniform particles particularly in microfluidics and biomedical area.