5 research outputs found
Ln[DO3A-N-α-(pyrenebutanamido)propionate] complexes: optimized relaxivity and NIR optical properties†
We have proposed recently that the DO3A-N-α-(amino)propionate chelator and its amide conjugates are
leads to targeted, high relaxivity, safe contrast agents for magnetic resonance imaging. In this work we
illustrate further the expeditious nature and robustness of the synthetic methodologies developed by preparing
the DO3A-N-(α-pyrenebutanamido)propionate chelator. Its Gd3+ chelate retains the optimized
water exchange, high stability and inertness of the parent complex. The pyrene moiety imparts concentration-
dependent self-assembly properties and aggregation-sensitive fluorescence emission to the Gd3+
complex. The Gd3+ complex displays pyrene-centred fluorescence whilst the Yb3+ and Nd3+ complexes
exhibit sensitized lanthanide-centred near-infrared luminescence. The aggregated form of the complex
displays high relaxivity (32 mM−1 s−1, 20 MHz, 25 °C) thanks to simultaneous optimization of the rotational
correlation time and of the water exchange rate. The relaxivity is however still limited by chelate flexibility.
This report demonstrates that the DO3A-N-(α-amino)propionate chelator is a valuable platform for constructing
high relaxivity CA using simple design principles and robust chemistries accessible to most
chemistry labs.This work was financially supported by Fundação para a
Ciência e Tecnologia, Portugal: project PTDC/QUI/70063/2006,
including a grant to C.I.O.M., grant SFRH/BD/63994/2009 to
M.F.F., grant SFRH/BD/46370/2008 to A.F.M. and sabbatical
grant SFRH/BSAB/ 1328/2013 to J.A.M. and Rede Nacional de
RMN (REDE/1517/RMN/2005) for the acquisition of the Varian
VNMRS 600 NMR spectrometer in Coimbra. The work in
France was supported by La Ligue contre le Cancer. This work
was carried out in the framework of the COST Actions D38
“Metal Based Systems for Molecular Imaging”, TD1004 “Theragnostic
Imaging” and CM1006 “EUFEN: European F-Element
Network”. S.P. acknowledges support from the Institut
National de la Santé et de la Recherche Médicale (INSERM)