Issue 31, 2018

Supramolecular assemblies based on amphiphilic Mn2+-complexes as high relaxivity MRI probes

Abstract

In the research field of MRI contrast agents (CAs), amphiphilic paramagnetic complexes are typically sought for the increased plasmatic half-life and high relaxivity values, but limited examples of amphiphilic Mn2+-based CAs have been reported to date. In this work the Mn2+-complexes of six original amphiphilic ligands (three EDTA-like ligands and three 1,4-DO2A derivatives) embodying one or two aliphatic chains were evaluated as potential MRI contrast agents and compared. Strong self-association into micelles resulted in a relaxivity (r1) enhancement (ca. 80% with respect to MnEDTA) as a consequence of the increased molecular tumbling rate of the supramolecular aggregate. In the case of bis-substituted systems the r1 gain is much higher due to the restricted local rotation of the chelates about the pendant aliphatic chains (r1 in the range 12.6–18.4 mM−1 s−1, 2–3 times higher than for the micelles obtained with single-chain EDTA systems). Furthermore, these amphiphilic chelates tightly bind to human serum albumin (HSA) with association constants KA in the range 104–105 M−1. The resulting supramolecular adducts achieve remarkable relaxivity values, in the range 50–60 mM−1 s−1 for the MnEDTA-like chelates and 27–30 mM−1 s−1 for the 1,4-DO2A-like systems (at 298 K and 20 MHz), thanks to their fast water exchange rate.

Graphical abstract: Supramolecular assemblies based on amphiphilic Mn2+-complexes as high relaxivity MRI probes

Supplementary files

Article information

Article type
Paper
Submitted
30 Mac 2018
Accepted
18 Mei 2018
First published
18 Mei 2018

Dalton Trans., 2018,47, 10660-10670

Supramolecular assemblies based on amphiphilic Mn2+-complexes as high relaxivity MRI probes

G. Rolla, V. De Biasio, G. B. Giovenzana, M. Botta and L. Tei, Dalton Trans., 2018, 47, 10660 DOI: 10.1039/C8DT01250D

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements