title: Synthesis of small-sized, porous, and low-toxic magnetite nanoparticles by thin POSS silica coating.
abstract: In this communication, we report the synthesis of small-sized (<10 nm), water-soluble, magnetic nanoparticles (MNPs) coated with polyhedral oligomeric silsesquioxanes (POSS), which contain either polyethylene glycol (PEG) or octa(tetramethylammonium) (OctaTMA) as functional groups. The POSS-coated MNPs exhibit superparamagnetic behavior with saturation magnetic moments (51-53 emu g(-1)) comparable to silica-coated MNPs. They also provide good colloidal stability at different pH and salt concentrations, and low cytotoxicity to MCF-7 human breast epithelial cells. The relaxivity data and magnetic resonance (MR) phantom images demonstrate the potential application of these MNPs in bioimaging.
authors: Institute of Materials Research and Engineering (IMRE), A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602 (Singapore).
authors: Swee Kuan
authors: SK
authors: Yen
authors: D Prathyusha
authors: DP
authors: Varma
authors: Wei Mei
authors: WM
authors: Guo
authors: Vincent H B
authors: VH
authors: Ho
authors: Vimalan
authors: V
authors: Vijayaragavan
authors: Parasuraman
authors: P
authors: Padmanabhan
authors: Kishore
authors: K
authors: Bhakoo
authors: Subramanian Tamil
authors: ST
authors: Selvan
mesh_terms: D004847:Epithelial Cells / Q000166:cytology* / Q000187:drug effects; D005290:Ferric Compounds / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D061986:MCF-7 Cells / Q000737:chemistry*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles; D017646:Organosilicon Compounds / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D016062:Porosity; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012822:Silicon Dioxide / Q000138:chemical synthesis* / Q000737:chemistry*
chemical_list: D005290:Ferric Compounds; D058185:Magnetite Nanoparticles; D017646:Organosilicon Compounds; D000644:Quaternary Ammonium Compounds; D011092:Polyethylene Glycols; D012822:Silicon Dioxide; C027917:tetramethylammonium
keywords: iron oxide; ligand exchange; magnetic properties; magnetic resonance imaging; nanoparticles