JBNB  Vol.4 No.3 , July 2013
Synthesis and Surface Modification of Spindle-Type Magnetic Nanoparticles: Gold Coating and PEG Functionalization

In this paper, we describe the synthesis of gold coated spindle-type iron nanoparticles and its surface modification by a thiolated fluorescently-labelled polyethylene glycol (PEG) polymer. A forced hydrolysis of ferric salts in the presence of phosphate ions was used to produce α-Fe2O3 spindle-type particles. The oxide powders were first reduced to α-iron under high temperature and controlled dihydrogen atmosphere. Then, the resulting magnetic spindle-type particles were covered by a shell of gold. The formation of the core@shell structure was driven by a redox-transmetalation reaction between iron(0) at the surface of particles and a gold(III) salt. Protected against oxidation, the Fe@Au core@shell nanoparticles were then grafted with a water soluble fluorescent-PEG-thiol. TEM, XRD, EDX and measurements of magnetic properties of particles confirm 1) the conversion of hematite into iron and 2) their subsequent surface protection with a gold shell. Furthermore, the functionalization of the gold nanoparticle surface with a PEG carrying a fluorescent dye was unambiguously attested by confocal laser scanning microscopy.

Cite this paper: J. Mendez-Garza, B. Wang, A. Madeira, C. Giorgio and G. Bossis, "Synthesis and Surface Modification of Spindle-Type Magnetic Nanoparticles: Gold Coating and PEG Functionalization," Journal of Biomaterials and Nanobiotechnology, Vol. 4 No. 3, 2013, pp. 222-228. doi: 10.4236/jbnb.2013.43027.

[1]   Y. N. Wu, D. H. Chen, X. Y. Shi, C. C. Lian, T. Y. Wang, C. S. Yeh, K. R. Ratinac, P. Thordarson, F. Braet and D. B. Shieh, “Cancer-Cell-Specific Cytotoxicity of Non-Oxidized Iron Elements in Iron Core-Gold Shell NPs,” Nanomedicine: Nanotechnology, Biology and Medicine, Vol. 7, No. 4, 2011, pp. 420-427. doi:10.1016/j.nano.2011.01.002

[2]   M. Chen, S. Yamamuro, D. Farrell and S. A. Majetich, “Gold-Coated Iron Nanoparticles for Biomedical Applications,” Journal of Applied Physics, Vol. 93, No. 10, 2003, pp. 7551-7553. doi:10.1063/1.1555312

[3]   K. Kandori and T. Ishikawa, “Preparation and Microstructural Studies on Hydrothermally Prepared Hematite,” Journal of Colloid and Interface Science, Vol. 272, No. 1, 2004, pp. 246-248. doi:10.1016/j.jcis.2003.08.075

[4]   T. Ishikawa and E. Matijevic, “Formation of Monodispersed Pure and Coated Spindle-Type Iron Particles,” Langmuir, Vol. 4, No. 1, 1988, pp. 26-31. doi:10.1021/la00079a004

[5]   M. Ocaña, M. P. Morales and C. J. Serna, “Homogeneous Precipitation of Uniform α-Fe2O3 Particles from Iron Salts Solutions in the Presence of Urea,” Journal of Colloid and Interface Science, Vol. 212, No. 2, 1999, pp. 317-323. doi:10.1006/jcis.1998.6042

[6]   X. L. Gou, G. X. Wang, J. Park, H. Liu and J. Yang, “Monodisperse Hematite Porous Nanospheres: Synthesis, Characterization, and Applications for Gas Sensors,” Nanotechnology, Vol. 19, No. 12, 2008, Article ID: 125606. doi:10.1088/0957-4484/19/12/125606

[7]   C. Baker, S. K. Hasanain and S. I. Shah, “The Magnetic Behavior of Iron Oxide Passivated Iron Nanoparticles,” Journal of Applied Physics, Vol. 96, No. 11, 2004, pp. 6657-6662. doi:10.1063/1.1806263

[8]   E. E. Carpenter, S. Calvin, R. M. Stroud and V. G. Harris, “Passivated Iron as Core-Shell Nanoparticles,” Chemical Materials, Vol. 15, No. 17, 2003, pp. 3245-3246. doi:10.1021/cm034131l

[9]   K. K. Fung, B. Qin and X. X. Zhang, “Passivation of α-Fe Nanoparticle by Epitaxial γ-Fe2O3 Shell,” Materials Science and Engineering: A, Vol. 286, No. 1, 2000, pp. 135138. doi:10.1016/S0921-5093(00)00717-6

[10]   S. H. Hu and X. Gao, “Nanocomposites with Spatially Separated Functionalities for Combined Imaging and Magnetolytic Therapy,” Journal of American Chemistry Society, Vol. 132, No. 21, 2010, pp. 7234-7237. doi:10.1021/ja102489q

[11]   D. H. Kim, E. A. Rozhkova, I. V. Ulasov, S. D. Bader, T. Rajh, M. S. Lesniak and V. Novosad, “Biofunctionalized Magnetic-Vortex Microdiscs for Targeted Cancer-Cell Destruction,” Natural Materials, Vol. 9, No. 2, 2010, pp. 165-171. doi:10.1038/nmat2591

[12]   S. Zalipsky and J. M. Harris, “Introduction to Chemistry and Biological Applications of Poly(Ethylene Glycol), in Poly(Ethylene Glycol),” American Chemical Society, 1997, pp. 1-13. doi:10.1021/bk-1997-0680.ch001

[13]   C. Leostean, O. Pana, R. Turcu, M. L. Soran, S. Macavei, O. Chauvet and C. Payen, “Comparative Study of CoreShell Iron/Iron Oxide Gold Covered Magnetic Nanoparticles Obtained in Different Conditions,” Journal of Nanoparticle Research, Vol. 13, No. 11, 2011, pp. 6181-6192. doi:10.1007/s11051-011-0313-3

[14]   Z. Ma, H. Han, S. Tu and J. Xue, “Fabrication of ShapeControlled Hematite Particles and Growth of Gold Nanoshells,” Colloids and Surfaces A: Physicochemical and Engineering Aspects, Vol. 334, No. 1-3, 2009, pp. 142-146. doi:10.1016/j.colsurfa.2008.10.015

[15]   H. Salehizadeh, E. Hekmatian, M. Sadeghi and K. Kennedy, “Synthesis and Characterization of Core-Shell Fe3O4Gold-Chitosan Nanostructure,” Journal of Nanobiotechnology, Vol. 10, No. 1, 2012, pp. 1-7. doi:10.1186/1477-3155-10-3

[16]   M. P. Morales, T. Gonazles-Carreño and C. J. Serna, “The Formation of a-Fe2O3 Mono-dispersed Particles in Solution,” Journal of Material Research, Vol. 7, 1992, pp. 2538-2545. doi:10.1557/JMR.1992.2538

[17]   W. R. Lee, M. G. Kim, J. R. Choi, J. L. Park, S. J. Ko, S. J. Oh and J. Cheon, “Redox-Transmetalation Process as a Generalized Synthetic Strategy for Core-Shell Magnetic Nanoparticles,” Journal of American Chemistry Society, Vol. 127, No. 46, 2005, pp. 16090-16097. doi:10.1021/ja053659j

[18]   S.-J. Cho, J.-C. Idrobo, J. Olamit, K. Liu, N. D. Browning and S. M. Kauzlarich, “Growth Mechanisms and Oxidation Resistance of Gold-Coated Iron Nanoparticles,” Chemistry of Materials, Vol. 17, No. 12, 2005, pp. 3181-3186. doi:10.1021/cm0500713

[19]   H. Danan, A. Herr and A. J. P. Meyer, “New Determinations of the Saturation Magnetization of Nickel and Iron,” Journal of Applied Physics, Vol. 39, No. 2, 1968, pp. 669-670. doi:10.1063/1.2163571