Magnetic Nanoparticles: Synthesis, Protection, Functionalization, and Application

Abstract

This review focuses on the synthesis, protection, functionalization, and application of magnetic nanoparticles, as well as the magnetic properties of nanostructured systems. Substantial progress in the size and shape control of magnetic nanoparticles has been made by developing methods such as co-precipitation, thermal decomposition and/or reduction, micelle synthesis, and hydrothermal synthesis. A major challenge still is protection against corrosion, and therefore suitable protection strategies will be emphasized, for example, surfactant/polymer coating, silica coating and carbon coating of magnetic nanoparticles or embedding them in a matrix/support. Properly protected magnetic nanoparticles can be used as building blocks for the fabrication of various functional systems, and their application in catalysis and biotechnology will be briefly reviewed. Finally, some future trends and perspectives in these research areas will be outlined.

Magnetic microreactors for efficient and reliable magnetic nanoparticle surface functionalization

“…2,3 Surface functionalization strategies have been established during recent years using standard bioconjugation techniques 4 , supramolecular or bioorthogonal chemistry 5 , or nanoparticles (NPs) such as gold 6 , which are almost readymade for coupling procedures due to their particular chemistry. Despite significant progress in the field, surface functionalization is usually achieved in a tedious process by adapting typical synthesis parameters such as reaction time, concentration or pH.…”

Magnetite (Fe3 O4 ) nanoparticles: Are they really safe?

“…Experimental studies have shown that metal and metal oxide nanoparticles induced DNA damage and apoptosis through ROS generation and oxidative stress (Ahamed et al, 2011). Fe 3 O 4 -NPs, in particular, could produce; oxidative stress following a direct route through Fe +2 and Fe +3 ions liberation from nanoparticles themself , by a surface catalytic action over H 2 O 2 (Lu et al, 2007) producing OH and OH − those are highly reactive species (Luo et al, 2014); and producing inflammation reactions (Ahamed et al, 2011;Choi et al, 2009). …”

Impurity-Induced Plasmon Damping in Individual Cobalt-Doped Hollow Au Nanoshells

“…(26) After allowing the reduction reaction to complete for 10 min under N 2 flow, 33 mL of the CoNP solution is added to a 0.1 M solution of chloroauric acid trihydrate (HAuCl 4 ·3H 2 O) in ambient air. As Co oxidizes, Au ions are reduced onto the CoNPs via galvanic replacement, since the reduction potential of gold is greater than the reduction potential of Co. (27) Cobalt nanoparticles (CoNPs) are known to exhibit a strong field-dependent magnetization and to align themselves into (magnetic) dipole chains (28,29) (Figure 1Ai). The Co-HGNS synthesis procedure prevents chain formation at the earliest stages by rapid vortexing; subsequent exposure of the solution during Au reduction to ambient air oxides the nanoparticle core, further reducing its magnetic response (Figure 1Aii, Aiii).…”