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Journal of Nanotechnology
Volume 2015, Article ID 848020, 8 pages
http://dx.doi.org/10.1155/2015/848020
Research Article

and Relaxivities of Dendrons Based on a OEG-DTPA Architecture: Effect of Gd3+ Placement and Dendron Functionalization

1Institute for Research in Biomedicine, Baldiri Reixac 10, 08028 Barcelona, Spain
2Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Spain
3Combinatorial Chemistry Unit, Barcelona Science Park, Baldiri Reixac 10, 08028 Barcelona, Spain
4Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Unitat de Biociències, Edifici C, 08193 Cerdanyola del Vallès, Spain
5Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Spain
6Department of Organic Chemistry, University of Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain
7School of Chemistry & Physics, University of KwaZulua-Natal, Durban 4001, South Africa

Received 23 December 2014; Revised 23 February 2015; Accepted 23 February 2015

Academic Editor: Paresh Chandra Ray

Copyright © 2015 Peter Fransen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

In magnetic resonance imaging, contrast agents are employed to enhance the signal intensity. However, current commercial contrast agents are hindered by a low relaxivity constant. Dendrimers can be employed to create higher molecular weight contrast agents which have an increased relaxivity due to a lower molecular rotation. In this study, dendrimers containing DTPA derivatives as cores and/or branching units were used to chelate gadolinium ions. Locating the gadolinium ions inside the dendrimers results in higher relaxivity constants, possibly because the paramagnetic center is closer to the rotational axis of the macromolecule. The highest gain in relaxivity was produced by decorating the dendron surface with peptide sequences, which could be explained by the presence of more second-sphere water molecules attracted by the peptides. These findings could contribute to the development of more effective contrast agents, either by placing the paramagnetic gadolinium ion in a strategic position or through functionalization of the dendron surface.