Preparation of monodisperse, superparamagnetic, luminescent, and multifunctional PGMA microspheres with amino-groups

Micron-sized, monodisperse, superparamagnetic, luminescent composite poly(glycidyl methacrylate) (PGMA) microspheres with functional amino-groups were successfully synthesized in this study. The process of preparation was as follows: preparation of monodisperse poly(glycidyl methacrylate) mi- crospheres by dispersion polymerization method; modification of poly(glycidyl methacrylate) micro- spheres with ethylene diamine to form amino-groups; impregnation of iron ions (Fe2+ and Fe3+) inside the microspheres and subsequently precipitating them with ammonium hydroxide to form magnetite (Fe3O4) nanoparticles within the polymer microspheres; infusion of CdSe/CdS core-shell quantum dots (QDs) into magnetic polymer microspheres. Scanning electron microscopy (SEM) was used to char- acterize surface morphology and size distribution of composite microspheres. The average size of mi- crospheres was 1.42 μm with a size variation of 3.8%. The composite microspheres were bright enough and easily observed using a conventional fluorescence microscope. The composite microspheres were easily separated from solution by magnetic decantation using a permanent magnet. The new multi- functional composite microspheres are promising to be used in a variety of bioanalytical assays in- volving luminescence detection and magnetic separation.

Micron-sized, monodisperse, superparamagnetic, luminescent composite poly（glycidyl methacrylate） （PGMA） microspheres with functional amino-groups were successfully synthesized in this study. The process of preparation was as follows： preparation of monodisperse poly（glycidyl methacrylate） microspheres by dispersion polymerization method; modification of poly（glycidyl methacrylate） microspheres with ethylene diamine to form amino-groups; impregnation of iron ions （Fe^2＋ and Fe^3＋） inside the microspheres and subsequently precipitating them with ammonium hydroxide to form magnetite （Fe3O4） nanoparticles within the polymer microspheres; infusion of CdSe/CdS core-shell quantum dots （QDs） into magnetic polymer microspheres. Scanning electron microscopy （SEM） was used to characterize surface morphology and size distribution of composite microspheres. The average size of microspheres was 1.42 μm with a size variation of 3.8%. The composite microspheres were bright enough and easily observed using a conventional fluorescence microscope. The composite microspheres were easily separated from solution by magnetic decantation using a permanent magnet. The new multifunctional composite microspheres are promising to be used in a variety of bioanalyUcal assays involving luminescence detection and magnetic separation.