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Biocompatible magnetite nanoparticles with varying silica‐coating layer for use in biomedicine: Physicochemical and magnetic properties, and cellular compatibility
Author(s) -
Singh Rajendra K.,
Kim TaeHyun,
Patel Kapil D.,
Knowles Jonathan C.,
Kim HaeWon
Publication year - 2012
Publication title -
journal of biomedical materials research part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.849
H-Index - 150
eISSN - 1552-4965
pISSN - 1549-3296
DOI - 10.1002/jbm.a.34140
Subject(s) - materials science , chemical engineering , biocompatibility , nanoparticle , coating , magnetic nanoparticles , zeta potential , surface modification , magnetization , particle size , aqueous solution , surface charge , polyethylene glycol , nanotechnology , organic chemistry , chemistry , physics , quantum mechanics , magnetic field , engineering , metallurgy
Magnetic nanoparticles (MNPs) are considered highly useful in therapeutic and diagnostic applications. However, MNPs require surface modification to promote dispersibility in aqueous solutions and thus biocompatibility. In this article, the authors modified MNPs with inorganic silica layer to create silica‐coated magnetite nanoparticles (MNP@Si) via sol–gel process. Synthesis involves hydrolysis and condensation steps using tetraethylorthosilicate (TEOS) in methanol/ polyethylene glycol (PEG) solution and ammonia catalyst. Nanoparticles were characterized in terms of morphology, particle size, crystalline phase, chemical‐bond structure, surface charge and magnetic properties: in particular, the MNP@Si size was easily tunable through alteration of the Fe 3 O 4 ‐to‐TEOS ratio. As this ratio increased, the MNP@Si size decreased from 270 to 15 nm whilst maintaining core 12‐nm MNP particle size, indicating decrease in thickness of the silica coating. All MNP@Si, in direct contrast to uncoated MNPs, showed excellent stability in aqueous solution. The particles' physicochemical and magnetic properties systematically varied with size (coating thickness), and the zeta potential diminished toward negative values, while magnetization increased as the coating thickness decreased. 15‐nm MNP@Si showed excellent magnetization (about 64.1 emu/g), almost comparable to that of uncoated MNPs (70.8 emu/g). Preliminary in vitro assays confirmed that the silica layer significantly reduced cellular toxicity as assessed by increase in cell viability and reduction in reactive oxygen species production during 48 h of culture. Newly‐developed MNP@Si, with a high capacity for magnetization, water‐dispersibility, and diminished cell toxicity, may be potentially useful in diverse biomedical applications, including delivery of therapeutic and diagnostic biomolecules. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.