Elaboration of fluorescent and highly magnetic submicronic polymer particles via a stepwise heterocoagulation process

Using the stepwise heterocoagulation concept, fluorescent and highly magnetic submicronic core-shell polymer particles were prepared. For this purpose a negatively charged oil-in-water magnetic emulsion was first modified by adsorbing the poly(ethyleneimine) (PEI). Secondly, low glass transition temperature (T _g=10°C) anionic film-forming nanoparticles were adsorbed onto the cationic magnetic droplets. Finally the encapsulation was induced by heating the heterocoagulates above the T _g of the film-forming nanoparticles. To produce labeled magnetic particles, fluorescent nanoparticles and film-forming nanoparticles were simultaneously adsorbed. PEI adsorption was investigated. Also investigated was the influence of the amount of film-forming nanoparticles and fluorescent nanoparticles on the encapsulation efficiency.