title: Solvent-free atom transfer radical polymerization for the preparation of poly(poly(ethyleneglycol) monomethacrylate)-grafted Fe3O4 nanoparticles: synthesis, characterization and cellular uptake.
abstract: Poly(poly(ethyleneglycol) monomethacrylate) (P(PEGMA))-grafted magnetic nanoparticles (MNPs) were successfully prepared via a solvent-free atom transfer radical polymerization (ATRP) method. The macroinitiators were immobilized on the surface of 6.4+/-0.8 nm Fe(3)O(4) nanoparticles via effective ligand exchange of oleic acid with 3-chloropropionic acid (CPA), which rendered the nanoparticles soluble in the PEGMA monomer. The so-obtained P(PEGMA)-grafted MNPs have a uniform hydrodynamic particle size of 36.0+/-1.2 nm. The successful grafting of P(PEGMA) on the MNP surface was ascertained from FTIR and XPS analyses. The uptake of the MNPs by macrophage cells is reduced by two-orders of magnitude to <2 pg Fe/cell after surface grafting with P(PEGMA). Furthermore, the morphology and viability of the macrophage cells cultured in a medium containing 0.2 mg/mL of P(PEGMA)-grafted MNPs were found similar to those of cells cultured without nanoparticles, indicating an absence of significant cytotoxicity effects. T(2)-weighted magnetic resonance imaging (MRI) of P(PEGMA)-grafted MNPs showed that the magnetic resonance signal is enhanced significantly with increasing nanoparticle concentration in water. The R(1) and R(2) values per millimole Fe, and R(2)/R(1) value of the P(PEGMA)-grafted MNPs were calculated to be 8.8 mm(-1)s(-1), 140 mm(-1)s(-1), and 16, respectively. These results indicate that the P(PEGMA)-grafted MNPs have great potential for application in MRI of specific biotargets.
authors: Department of Diagnostic Radiology, National University of Singapore, Kent Ridge, Singapore 119260, Singapore.
authors: Qu-Li
authors: QL
authors: Fan
authors: Koon-Gee
authors: KG
authors: Neoh
authors: En-Tang
authors: ET
authors: Kang
authors: Borys
authors: B
authors: Shuter
authors: Shih-Chang
authors: SC
authors: Wang
mesh_terms: D000818:Animals; D002460:Cell Line; D002463:Cell Membrane Permeability / Q000187:drug effects; D005290:Ferric Compounds / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D005609:Free Radicals / Q000737:chemistry; D008279:Magnetic Resonance Imaging; D008280:Magnetics; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D008689:Methacrylates / Q000737:chemistry*; D051379:Mice; D046529:Microscopy, Electron, Transmission; D015394:Molecular Structure; D011092:Polyethylene Glycols / Q000737:chemistry*; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry; D012997:Solvents; D013057:Spectrum Analysis
chemical_list: D005290:Ferric Compounds; D005609:Free Radicals; D008689:Methacrylates; D011108:Polymers; D012997:Solvents; C524499:polyethylene glycol methacrylate; D011092:Polyethylene Glycols