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Surface Functionalization of Single Superparamagnetic Iron Oxide Nanoparticles for Targeted Magnetic Resonance Imaging
Author(s) -
Amstad Esther,
Zurcher Stefan,
Mashaghi Alireza,
Wong Joyce Y.,
Textor Marcus,
Reimhult Erik
Publication year - 2009
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.200801328
Subject(s) - materials science , quartz crystal microbalance , nanoparticle , peg ratio , surface modification , biotinylation , ethylene glycol , iron oxide nanoparticles , magnetic nanoparticles , nanotechnology , surface plasmon resonance , iron oxide , dispersion stability , superparamagnetism , gadolinium , chemical engineering , chemistry , magnetization , adsorption , organic chemistry , biochemistry , physics , finance , quantum mechanics , engineering , magnetic field , economics , metallurgy
Magnetic resonance imaging (MRI), a non‐invasive, non‐radiative technique, is thought to lead to cellular or even molecular resolution if optimized targeted MR contrast agents are introduced. This would allow diagnosing progressive diseases in early stages. Here, it is shown that the high binding affinity of poly(ethylene glycol)‐gallol (PEG‐gallol) allows freeze drying and re‐dispersion of 9 ± 2‐nm iron oxide cores individually stabilized with ≈9‐nm‐thick stealth coatings, yielding particle stability for at least 20 months. Particle size, stability, and magnetic properties of PEGylated particles are compared to Feridex, a commercially available untargeted negative MR contrast agent. Biotin‐PEG(3400)‐gallol/methoxy‐PEG(550)‐gallol stabilized nanoparticles are further functionalized with biotinylated human anti‐VCAM‐1 antibodies using the biotin–neutravidin linkage. Binding kinetics and excellent specificity of these nanoparticles are demonstrated using quartz crystal microbalance with dissipation monitoring (QCM‐D). These MR contrast agents can be functionalized with any biotinylated ligand at controlled ligand surface density, rendering them a versatile research tool.