Facile Method for Preparation of Silica Coated Monodisperse Superparamagnetic Microspheres

Abstract

This paper presents a facile method for preparation of silica coated monodisperse superparamagnetic microsphere. Herein, monodisperse porous polystyrene-divinylbenzene microbeads were prepared by seeded emulsion polymerization and subsequently sulfonated with acetic acid/H2SO4. The as-prepared sulfonated macroporous beads were magnetized in presence of Fe2+/Fe3+under alkaline condition and were subjected to silica coating by sol-gel process, providing water compatibility, easily modifiable surface form, and chemical stability. FE-SEM, TEM, FT-IR, and TGA were employed to characterize the silica coated monodisperse magnetic beads (~7.5 μm). The proposed monodisperse magnetic beads can be used as mobile solid phase particles candidate for protein and DNA separation.

Silica-Coated Magnetic Iron Oxide Nanoparticles Grafted onto Graphene Oxide for Protein Isolation

“…The magnetic property of the GO/MNP@SiO 2 was investigated by using a PPMS-9 vibrating sample magnetometer. The saturation magnetization of the GO/MNPs@SiO 2 was determined to be 9.53 emu/g at magnetic field of 2.0 (T), which is higher than the magnetization of MNPs in previous reports [40,60] (Figure 6a). The magnetization as the function of applied field showed a reversible S-shape and no remnant magnetization is obtained, indicating a superparamagnetic behavior of the GO/MNP@SiO 2 .…”

Surface-Initiated Living Anionic Polymerization of Functional Methacrylates from the Surface of Organic Particles

“…65 Since the conversion of polymer analogous reactions is considered to be seldom complete, a onestep reaction was preferred instead of the three-step reaction to investigate the functional group accessibility. For these reasons and in addition to established conditions in DMSO at room temperature, 67 the functionalization was carried out at a higher temperature in an alkaline solvent (pyridine). The success of the functionalization could already be concluded in terms of the observed particles' color after several purification steps, whereby the particles of the more alkaline functionalization route (PSDVB@PHEMA-01-FITC-b) revealed a higher yellow coloration (Figure S5), which originated from the yellow-orange color of FITC 7.…”

Spectrally encoded microspheres for immunofluorescence analysis

“…143 Generally, magnetic polymeric beads are composed solely of magnetic particles coupled with the polymeric matrix, however, in some cases, silica coatings, for example, may provide colloidal stability and biocompatibility, as well as required surface functionality. 144 The methods for the synthesis of monodisperse polymer/silicon magnetic particles in literature vary from the seed polymerization method, for example, silica coated particles with styrene core 145 to emulsion and dispersion polymerization, for example, monodisperse 0.5, 1, and 2 μm spheres. 120 Silicone magnetic spheres are also designed for replacing magnetic PS spheres in applications where either large magnetic forces or minimal autofluorescence is required.…”