Novel fluorescent poly(glycidyl methacrylate) – Silica microspheres

Abstract Monodisperse macroporous poly(glycidyl methacrylate) (PGMA) microspheres were prepared by multiple swelling polymerization using a modified Ugelstad method. The outer and inner parts of PGMA microspheres were coated with silica (SiO 2 ) using tetramethyl othosilicate (TMOS) and trimethoxy(methyl)silane (TMMS) to produce PGMA&SiO 2 and PGMA&Me SiO 2 hybrid particles, respectively. In order to introduce amino groups, the microsphere surface was functionalized with (3-aminopropyl)diethoxy(methyl)silane (APDMS) and (3-aminopropyl)triethoxysilane (APTES) resulting in PGMA&SiO 2 NH 2 and PGMA&Me SiO 2 NH 2 particles, respectively. The particles were characterized by SEM and TEM coupled with energy dispersive X-ray analysis (EDAX) and FT-IR spectroscopy to determine morphology, particle size, polydispersity and the presence of functional groups. Elemental and thermogravimetric (TGA) analyses were used for determination of the formed SiO 2 . Moreover, specific surface areas of the hybrid microspheres were determined by dynamic adsorption of nitrogen. In biological experiments, PGMA, PGMA&SiO 2 and PGMA&SiO 2 NH 2 microspheres demonstrated good biocompatibility in vitro , since no significant increase in the amount of dead (Trypan Blue) human Jurkat T cells was observed when the microsphere concentrations in the medium increased from 0.1 to 1 μg/ml. The microspheres exhibited red and green fluorescence. The former increased in the order PGMA  2 2 NH 2 . The PGMA&SiO 2 NH 2 microspheres did not significantly swell at pH 7.0–9.5. They were capable of binding biomacromolecules, e.g., bovine serum albumin by adsorption or Dextran Blue by covalent binding.