A novel class of 1H-MRI Contrast Agents based on the relaxation enhancement induced on water protons by 14N imidazole moieties

Simona Baroni, R. Stefania, Lionel Broche, Nicholas Senn, David Lurie, James J Ross, Silvio Aime, S Geninatti Crich* (Corresponding Author)

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)
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This study aims at developing a completely new class of MRI contrast agents, displaying remarkable relaxation effects in the absence of paramagnetic metal ions. Their detection requires the acquisition of images at variable magnetic field strength as provided by Fast Field Cycling imaging scanners. They contain poly-histidine chains (poly-His), whose imidazole groups generate 14N-QuadrupolarPeaks that cause a relaxation enhancement of water protons at a frequency (1.38±0.3 MHz) that is readily detectable from the frequencies associated with endogenous proteins. The poly-His QPs are detectable only when the polymer is in a solid-like form, i.e. at pH > 6.6. Above this value, their intensity is pH dependent and can beused to report on the occurring pH changes. On this basis, the polyHis moieties were conjugated to biocompatible polymers such aspolylactic and glycolic acid, in order to form stable nanoparticles ableto encapsulate structured water in their core. FFC images were acquired to assess their contrast-generating ability.
Original languageEnglish
Pages (from-to)4208-4214
Number of pages7
JournalAngewandte Chemie International Edition
Issue number8
Early online date15 Dec 2020
Publication statusPublished - 19 Feb 2021

Bibliographical note

This project has received funding from the European Union Horizon 2020 research and innovation programme under grant agreement No 668119 (project “IDentIFY”) and from the ATTRACT project funded by the EC under Grant Agreement No.777222. This work was performed in the frame of the COST Action AC15209 (EURELAX). The Italian Ministry for Educationand Research (MIUR) is gratefully acknowledged for yearly FOE funding to the Euro-BioImaging Multi-Modal Molecular Imaging Italian Node (MMMI).


  • Magnetic Resonance Imaging
  • contrast agents
  • 14N quadrupolar peaks
  • fast field cycling
  • nanoparticles
  • magnetic resonance imaging
  • peptides
  • biosensors
  • N-14


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