Advanced nanoassemblies of paramagnetic amphiphilic chelates as MRI contrast agents

Introduction: Supramolecular nanoparticles made from the self-assembly of paramagnetic amphiphilic chelates, hereafter referred to as paramagnetic nanoassemblies, have many properties deemed necessary for an ideal magnetic resonance imaging (MRI) contrast agent. These include slow molecular reorientation, ability to deliver high payloads of paramagnetic metal ions, ease of altering their sizes, their ability to passively target tumours through enhanced permeation and retention, and the possibility of incorporating (active) targeting moieties or therapeutic drugs within their framework. Although, liposomes and micelles have been extensively explored as MRI contrast agents,1 advanced supramolecular structures such as cubosomes and hexosomes, capable of delivering a much higher payload of paramagnetic metal ions, have received limited attention. This presentation reports on the design, synthesis, characterisation and relaxation properties of the highly ordered supramolecular nanoassemblies of novel paramagnetic amphiphilic chelates as advanced MRI contrast agents. In addition, the development and characterisation of hypoxia (oxygen deprived tumorous tissue)-specific paramagnetic liposomes is also presented with a view to extend the hypoxia targeting ability to the advanced supramolecular structures.