In this study, iron oxide (IO) nanoparticles from various precursors have been synthesized using sonochemical method and characterized for their structural variability and toxicity. The iron oxide (IO) precursor solutions were prepared from iron acetate (IA), iron pentacarbonyl (IP), decalin, PEG (poly(ethylene glycol)), EG (ethylene glycol), PVA (poly(vinyl alcohol)), β-cyclodextrin (CD), and distilled water. These precursor solutions were irradiated with high power ultrasound for 3 hours and heat treated as needed. These as-prepared iron oxide nanoparticles were characterized using X-ray diffraction (XRD), M？ssbauer spectroscopy, transmission electron microscopy (TEM), and magnetization measurements. XRD results show that all the particles are highly crystalline in nature and the particles sizes measured from TEM are approximately 5–20？nm. The maximum magnetization was observed for IO-IP at approximately 60.17？emu/g and the minimum was approximately 30.56？emu/g for IO-IA. These results confirm that the particles are superparamagnetic (SPM) in nature. M？ssbauer spectroscopy verified the magnetic nanoparticles are purely Fe3O4 and particles sizes varied by the nature of the precursor and coatings. 1. Introduction Iron based nanomaterials have found applications in many areas of science and technology due to their unique magnetic properties [1–5]. Recently, they are also used in biomedical applications such as MRI contrast agents for imaging [6], magnetic hyperthermia [7], and targeted drug delivery [8] because of their size compatibility [9] to cells, genes, and viruses. A size reduction of these materials from bulk to the nanoscale permits them to display various size related properties. Among other changes, a significant decrease in size can alter reactivity, increase surface area, and change the magnetic properties [10–12]. Iron oxide, for example, exhibits ferromagnetic behavior in bulk where it can reach full magnetization and the effect persists even after removal of the magnetic field. These same particles below a certain size (<20？nm) may exhibit a behavior similar to paramagnetism even when at temperatures below the Curie point. This is a nanoscale phenomenon, where the energy required to change the direction of the magnetic moment of a particle is comparable to the ambient thermal energy. The energy required to change the direction of magnetization of a crystallite is called the crystalline anisotropy energy and depends both on the material properties and the crystallite size. As the crystallite size decreases, so does the crystalline
References
[1]
D. L. J. Thorek, A. K. Chen, J. Czupryna, and A. Tsourkas, “Superparamagnetic iron oxide nanoparticle probes for molecular imaging,” Annals of Biomedical Engineering, vol. 34, no. 1, pp. 23–38, 2006.
[2]
E. Amstad, T. Gillich, I. Bilecka, M. Textor, and E. Reimhult, “Ultrastable iron oxide nanoparticle colloidal suspensions using dispersants with catechol-derived anchor groups,” Nano Letters, vol. 9, no. 12, pp. 4042–4048, 2009.
[3]
R. Qiao, C. Yang, and M. Gao, “Superparamagnetic iron oxide nanoparticles: from preparations to in vivo MRI applications,” Journal of Materials Chemistry, vol. 19, no. 35, pp. 6274–6293, 2009.
[4]
S. T. Amyn and K. Pei-Yoong, “Synthesis, properties, and applications of magnetic iron oxide nanoparticles,” Progress in Crystal Growth and Characterization of Materials, vol. 55, no. 1-2, pp. 22–45, 2009.
[5]
L. Wang, J. Luo, M. M. Maye et al., “Iron oxide-gold core-shell nanoparticles and thin film assembly,” Journal of Materials Chemistry, vol. 15, no. 18, pp. 1821–1832, 2005.
[6]
K. Tanaka, N. Kitamura, M. Morita, T. Inubushi, and Y. Chujo, “Assembly system of direct modified superparamagnetic iron oxide nanoparticles for target-specific MRI contrast agents,” Bioorganic and Medicinal Chemistry Letters, vol. 18, no. 20, pp. 5463–5465, 2008.
[7]
M. Gonzales-Weimuller, M. Zeisberger, and K. M. Krishnan, “Size-dependant heating rates of iron oxide nanoparticles for magnetic fluid hyperthermia,” Journal of Magnetism and Magnetic Materials, vol. 321, no. 13, pp. 1947–1950, 2009.
[8]
B. Gaihre, M. S. Khil, D. R. Lee, and H. Y. Kim, “Gelatin-coated magnetic iron oxide nanoparticles as carrier system: drug loading and in vitro drug release study,” International Journal of Pharmaceutics, vol. 365, no. 1-2, pp. 180–189, 2009.
[9]
D. L. Leslie-Pelecky, V. D. Labhasetwar, and R. H. Kraus, Advanced Magnetic Nanostructures, Kluwer, New York, NY, USA, 2007.
[10]
D. K. Kim, Y. Zhang, W. Voit, K. V. Rao, and M. Muhammed, “Synthesis and characterization of surfactant-coated superparamagnetic monodispersed iron oxide nanoparticles,” Journal of Magnetism and Magnetic Materials, vol. 225, no. 1-2, pp. 30–36, 2001.
[11]
T. Neuberger, B. Sch？pf, H. Hofmann, M. Hofmann, and B. Von Rechenberg, “Superparamagnetic nanoparticles for biomedical applications: possibilities and limitations of a new drug delivery system,” Journal of Magnetism and Magnetic Materials, vol. 293, no. 1, pp. 483–496, 2005.
[12]
R. Asmatulu, M. A. Zalich, R. O. Claus, and J. S. Riffle, “Synthesis, characterization and targeting of biodegradable magnetic nanocomposite particles by external magnetic fields,” Journal of Magnetism and Magnetic Materials, vol. 292, pp. 108–119, 2005.
[13]
V. P. Torchilin, “Drug targeting,” European Journal of Pharmaceutical Sciences, vol. 11, no. 2, pp. S81–S91, 2000.
[14]
F. C. Maluf and D. Spriggs, “Anthracyclines in the treatment of gynecologic malignancies,” Gynecologic Oncology, vol. 85, no. 1, pp. 18–31, 2002.
[15]
M. A. Morales, T. K. Jain, V. Labhasetwar, and D. L. Leslie-Pelecky, “Magnetic studies of iron oxide nanoparticles coated with oleic acid and Pluronic block copolymer,” Journal of Applied Physics, vol. 97, no. 10, Article ID 10Q905, 3 pages, 2005.
[16]
I. Banerjee, Y. B. Khollam, C. Balasubramanian et al., “Preparation of γ-Fe2O3 nanoparticles using DC thermal arc-plasma route, their characterization and magnetic properties,” Scripta Materialia, vol. 54, no. 7, pp. 1235–1240, 2006.
[17]
Z. Surowiec, M. Wiertel, M. Budzyński, J. Sarzyński, and J. Goworek, “Magnetite nanowires in MCM-41 type mesoporous silica templates,” Journal of Non-Crystalline Solids, vol. 354, no. 35–39, pp. 4271–4274, 2008.
[18]
P. Tartaj, M. Del Puerto Morales, S. Veintemillas-Verdaguer, T. González-Carre？o, and C. J. Serna, “The preparation of magnetic nanoparticles for applications in biomedicine,” Journal of Physics D, vol. 36, no. 13, pp. R182–R197, 2003.
[19]
J. Huang, H. Pen, Z. Xu, and C. Yi, “Magnetic Fe3O4/poly(styrene-co-acrylamide) composite nanoparticles prepared by microwave-assisted emulsion polymerization,” Reactive and Functional Polymers, vol. 68, no. 1, pp. 332–339, 2008.
[20]
J. Pinkas, V. Reichlova, R. Zboril, Z. Moravec, P. Bezdicka, and J. Matejkova, “Sonochemical synthesis of amorphous nanoscopic iron(III) oxide from Fe(acac)3,” Ultrasonics Sonochemistry, vol. 15, no. 3, pp. 257–264, 2008.
[21]
K. S. Suslick, S. B. Choe, A. A. Cichowlas, and M. W. Grinstaff, “Sonochemical synthesis of amorphous iron,” Nature, vol. 353, no. 6343, pp. 414–416, 1991.
[22]
R. Vijayakumar, Y. Koltypin, I. Felner, and A. Gedanken, “Sonochemical synthesis and characterization of pure nanometer-sized Fe3O4 particles,” Materials Science and Engineering A, vol. 286, no. 1, pp. 101–105, 2000.
[23]
A. Gedanken, “Using sonochemistry for the fabrication of nanomaterials,” Ultrasonics Sonochemistry, vol. 11, no. 2, pp. 47–55, 2004.
[24]
G. Q. Zhang, H. P. Wu, M. Y. Ge, Q. K. Jiang, L. Y. Chen, and J. M. Yao, “Ultrasonic-assisted preparation of monodisperse iron oxide nanoparticles,” Materials Letters, vol. 61, no. 11-12, pp. 2204–2207, 2007.
[25]
A. Gedanken, Ultrasonic Processing to Produce Nanoparticles, Encyclopedia of Materials, Science and Technology Elsevier Science, Oxford, UK, 2008.
[26]
P. Dallas, A. B. Bourlinos, D. Niarchos, and D. Petridis, “Synthesis of tunable sized capped magnetic iron oxide nanoparticles highly soluble in organic solvents,” Journal of Materials Science, vol. 42, no. 13, pp. 4996–5002, 2007.
[27]
R. V. Ramanujan and Y. Y. Yeow, “Synthesis and characterisation of polymer-coated metallic magnetic materials,” Materials Science and Engineering C, vol. 25, no. 1, pp. 39–41, 2005.
[28]
J. L. Arias, V. Gallardo, S. A. Gómez-Lopera, R. C. Plaza, and A. V. Delgado, “Synthesis and characterization of poly(ethyl-2-cyanoacrylate) nanoparticles with a magnetic core,” Journal of Controlled Release, vol. 77, no. 3, pp. 309–321, 2001.
[29]
L. Seung-Jun, J. Jong-Ryul, S. Sung-Chul et al., “Magnetic enhancement of iron oxide nanoparticles encapsulated with poly(D,L-latide-co-glycolide),” Colloids and Surfaces A, vol. 255, no. 1–3, pp. 19–25, 2005.
[30]
H. Yaci Acar, R. S. Garaas, F. Syud, P. Bonitatebus, and A. M. Kulkarni, “Superparamagnetic nanoparticles stabilized by polymerized PEGylated coatings,” Journal of Magnetism and Magnetic Materials, vol. 293, no. 1, pp. 1–7, 2005.
[31]
P. J. Reséndiz-Hernández, O. S. Rodríguez-Fernández, and L. A. García-Cerda, “Synthesis of poly(vinyl alcohol)-magnetite ferrogel obtained by freezing-thawing technique,” Journal of Magnetism and Magnetic Materials, vol. 320, pp. e373–e376, 2008.
[32]
T. K. Jain, M. A. Morales, S. K. Sahoo, D. L. Leslie-Pelecky, and V. Labhasetwar, “Iron oxide nanoparticles for sustained delivery of anticancer agents,” Molecular Pharmaceutics, vol. 2, no. 3, pp. 194–205, 2005.
[33]
S. Hanessian, J. A. Grzyb, F. Cengelli, and L. Juillerat-Jeanneret, “Synthesis of chemically functionalized superparamagnetic nanoparticles as delivery vectors for chemotherapeutic drugs,” Bioorganic and Medicinal Chemistry, vol. 16, no. 6, pp. 2921–2931, 2008.
[34]
X. Cao, “Preparation and characterization of amorphous nanometre sized Fe3O4 powder,” Journal of Materials Chemistry, vol. 7, no. 6, pp. 1007–1009, 1997.
[35]
S. R. Elliott, Physics of Amorphous Materials, Longman, London, UK, 1984.
[36]
C. C. Daniela, M. Gabriela, P. Lumini？a, and D. Lucian, “Synthesis and characterization of maltol modified magnetite nanoparticles,” Revue Roumaine de Chimie, vol. 55, no. 2, pp. 131–135, 2010.
[37]
N. N. Greenwood and T. C. Gibb, M？ssbauer Spectroscopy, Chapman and Hall, London, UK, 1971.
[38]
K. R. Vijaya, Y. Koltypin, X. N. Xu, Y. Yeshurun, A. Gedanken, and I. Felner, “Fabrication of magnetite nanorods by ultrasound irradiation,” Journal of Applied Physics, vol. 89, no. 11, p. 6324, 2001.
[39]
W. Kündig, H. B？mmel, G. Constabaris, and R. H. Lindquist, “Some properties of supported small α-Fe2O3 particles determined with the M？ssbauer effect,” Physical Review, vol. 42, no. 2, pp. 327–333, 1966.
