Surface Modification of Magnetic Iron Oxide Nanoparticles

Abstract

Functionalized iron oxide nanoparticles (IONPs) are of great interest due to wide range applications, especially in nanomedicine. However, they face challenges preventing their further applications such as rapid agglomeration, oxidation, etc. Appropriate surface modification of IONPs can conquer these barriers with improved physicochemical properties. This review summarizes recent advances in the surface modification of IONPs with small organic molecules, polymers and inorganic materials. The preparation methods, mechanisms and applications of surface-modified IONPs with different materials are discussed. Finally, the technical barriers of IONPs and their limitations in practical applications are pointed out, and the development trends and prospects are discussed.

Keywords: iron oxide nanoparticles; magnetic nanoparticles; nanomedicine; surface modification.

Figure 1

Typical morphologies of magnetic composite nanomaterials. Reproduced with permission from [50]. Copyright Institute of Physics, 2015.

Figure 2

Transmission electron microscope (TEM) image of 12.2-nm Fe₃O₄@SiO₂ nanoparticles (NPs) with shell thicknesses of (a) 2.0 nm, (b) 6.3 nm, (c) 14.1 nm, and (d) 19.8 nm. Scale bar = 20 nm. Reproduced with permission from [65]. Copyright American Chemical Society, 2012.

Figure 3

Illustration of the coating mechanism of SiO₂ on the Surface of Fe₃O₄ NPs. Reproduced with permission from [62]. Copyright American Chemical Society, 2012.

Scheme 1

Schematic illustration of flame synthesis and in situ selective modification of double-faced g-Fe₂O₃||SiO₂ NHs. Reproduced with permission from [67]. Copyright Royal Society of Chemistry, 2013.

Scheme 2

Schematic formation mechanism of three-dimensional Fe₃O₄/rGO hybrids. Reproduced with permission from [113]. Copyright American Chemical Society, 2017.

Scheme 3

Schematic illustration of the two routes for gold coating. Reproduced with permission from [120]. Copyright Royal Society of Chemistry, 2016.

Scheme 4

Schematic illustration of the bifunctional Fe₃O₄/Au nanocomposites. Reproduced with permission from [124]. Copyright Elsevier, 2014.

Scheme 5

Preparation procedure of Fe₃O₄@PZS@Au shells. Reproduced with permission from [131]. Copyright American Chemical Society, 2013.

Scheme 6

A proposed photocatalytic reaction mechanism of the Fe₃O₄@ZnO. Reproduced with permission from [150]. Copyright Elsevier, 2014.

Scheme 7

Schematic illustration of the synthesis of PEG/PVP-coated superparamagnetic iron oxide nanoparticles (SPIONs). Reproduced with permission from [180]. Copyright Elsevier, 2013.

Scheme 8

Physicochemical mechanism for modifying the silane agents on the surface of iron oxide NPs. Reproduced with permission from [155]. Copyright Wei Wu, 2008.