Architectured design of superparamagnetic Fe3O4nanoparticles for application as MRI contrast agents: mastering size and magnetism for enhanced relaxivity

• DOI: 10.1039/c5tb00789e
• Publication Date: 2015-06-26T15:01:37Z
• Authors: Clara Pereira; André M. Pereira; Mariana Rocha; Cristina Freire; Carlos F. G. C. G...
• Keywords: Nanomaterials; Coprecipitation; Superparamagnetism; Magnetism; Diethanolamine; Triethanolamine; Dispersity; Diamagnetism; Nanodot; Surface Modification; MRI contrast agent

This work reports the mastered design of novel water-dispersible superparamagnetic iron oxide nanomaterials with enhanced magnetic properties and reduced size. A straightforward cost-effective aqueous coprecipitation route was developed, based on use three new agents: polydentate bases diethanolamine, triethanolamine triisopropanolamine. Through selection these alkanolamines which presented different complexing properties, an improvement surface spin order could be achieved upon reduction nanomaterial dimensions (from 8.7 to 3.8 nm) owing complexation subcoordinated cations particle surface. In particular, alkanolamine highest chelating ability (triethanolamine) led smallest size thinnest "dead" layer. evaluate importance dual control magnetism, relaxometric were investigated, whereby maximum values transverse relaxivity r2 300.30 253.92 mM-1 s-1 at 25 37 °C, respectively (at 20 MHz) achieved, making potential T2-weighted MRI contrast agents. Moreover, significantly higher than those reported for commercial T2 agents other oxides identical dimensions. Hence, we able demonstrate that enhancement cannot only by increase particle/cluster size, but also through precise while constraining These achievements open up perspectives nanoprobes, overcoming limitations related deleterious effect reduction.