Fluorescent Reactive Core–Shell Composite Nanoparticles with A High Surface Concentration of Epoxy Functionalities

A method for the synthesis of fluorescent core–shell nanoparticles with reactive epoxide functional groups on the surface has been developed as a platform for the generation of functional and labeled nanoparticles for diverse applications. Namely, poly(glycidyl methacrylate), PGMA, was used to form a reactive and fluorescent shell on the nanoparticle surface. Prior to deposition on the silica nanoparticle, the PGMA was fluorescently labeled with Rhodamine B via a reaction between the epoxy groups of the polymer and carboxyl groups of the dye. A strong fluorescence emission was observed for the colloidal suspension of the modified nanoparticles. Atomic force microscopy, dynamic light scattering, and thermogravimetric and elemental analysis were used to characterize the nanoparticles. The reactive nanoparticles are a convenient and straightforward platform to generate fluorescent particles with various molecules attached to their exterior, because epoxy groups (located on the particle exterior) are highly active in various chemical reactions. Reactivity of the particles was confirmed via modification of the surface of polyester fibers with the nanoparticles and synthesis of polymer grafted layers on their surface using “grafting to” and “grafting from” approaches. The newly designed technique will be applicable toward particles made from a wide variety of organic and inorganic materials, as long as the surface of material contains functional groups reactive with epoxy moiety.