Supramolecular assemblies based on amphiphilic Mn2+-complexes as high relaxivity MRI probes.
Gabriele RollaValeria De BiasioGiovanni Battista GiovenzanaMauro BottaLorenzo TeiPublished in: Dalton transactions (Cambridge, England : 2003) (2018)
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.
Keyphrases
- contrast enhanced
- magnetic resonance imaging
- magnetic resonance
- crispr cas
- drug delivery
- diffusion weighted imaging
- human serum albumin
- genome editing
- room temperature
- computed tomography
- energy transfer
- cancer therapy
- small molecule
- drug release
- hyaluronic acid
- metal organic framework
- molecular docking
- ionic liquid
- climate change
- crystal structure