Improved functionalization of oleic acid-coated iron oxide nanoparticles for biomedical applications

Abstract

Superparamagnetic iron oxide nanoparticles can provide multiple benefits for biomedical applications in aqueous environments such as magnetic separation or magnetic resonance imaging. To increase the colloidal stability and allow subsequent reactions, the introduction of hydrophilic functional groups onto the particles’ surface is essential. During this process, the original coating is exchanged by preferably covalently bonded ligands such as trialkoxysilanes. The duration of the silane exchange reaction, which commonly takes more than 24 h, is an important drawback for this approach. In this paper, we present a novel method, which introduces ultrasonication as an energy source to dramatically accelerate this process, resulting in high-quality water-dispersible nanoparticles around 10 nm in size. To prove the generic character, different functional groups were introduced on the surface including polyethylene glycol chains, carboxylic acid, amine, and thiol groups. Their colloidal stability in various aqueous buffer solutions as well as human plasma and serum was investigated to allow implementation in biomedical and sensing applications.Electronic supplementary materialThe online version of this article (doi:10.1007/s11051-012-1100-5) contains supplementary material, which is available to authorized users.

Effect of Surface Charge and Hydrophobicity Modulation on the Antibacterial and Antibiofilm Potential of Magnetic Iron Nanoparticles

“…Functionalizing MNPs with OA resulted in an increase in negative potential to −29.2 mV [35,44]. To synthesize positive charge shifted MNPs, Arg (amino acid) induced a charge shift from −18 to −6 mV [45][46][47].…”

Fatty acid as structure directing agent for controlled secondary growth of CoFe2O4 nanoparticles to achieve mesoscale assemblies: A facile approach for developing hierarchical structures

“…However, escaping this usual trend of intensity variation with oleic acid concentration, CF2, i.e., the assembly sample shows two highest intense peaks at 1115 cm −1 and 949 cm −1 , which are attributed to C O stretching and out-of-plane O H bending vibrations [28,31]. Moreover, one additional peak is observed for this sample at 1482 cm −1 which is ascribed to the in-plane O H bending vibrations [32]. Thus, the observed intense peak of C O stretching and O H bending vibra- tions for the CF2 sample means that, there might be a fraction of oleic acid molecules which are in quasi-boding state.…”

Síntesis y estudio de propiedades estructurales y magnéticas de ferritas Mg1-xZnxFe2O4 (x= 0-0,9)

“…A partir de estos espectros fue posible identificar bandas de absorción que corresponden a los estiramientos simétricos y asimétricos de los enlaces CH 2 (2922 y 2840 cm -1 ), del grupo funcional COO -(1536 y 1391 cm -1 ) y de los enlaces C-O (1017 cm-1) característicos de moléculas de AO unidas química-mente a la superficie de las partículas en forma de carboxilato [2,17]. La formación del óxido magnético puede ser confirmada tomando en cuenta una banda de absorción en aproximadamente 546 cm -1 y que corresponde al estiramiento del enlace Metal-Oxígeno (Fe-O, Mg-O y Zn-O) de los complejos octaédricos y tetraédricos de la espinela [18]. …”