Introduction

The compounds object of the invention are a new metal-free class of contrast agents for magnetic resonance, whose action is based on an innovative mechanism that do not use potentially toxic metals. The compounds work at fixed frequencies and they may be used for the design of nano- and micro- devices reporting on local pathological and physiological changes, in vitro and in vivo.

Technical features

The compounds, immobilized in biocompatible polymers, contain histidine in polymeric form. The imidazole group of histidine produces a significant reduction in the relaxation time at the magnetic field value where the proton frequency and the nitrogen nuclear quadrupole resonance frequency coincide (quadrupolar peaks). They  generate an image contrast at frequencies well distinguishable from the one associated with the amidic peptide bonds from endogenous proteins. They are pH- sensitive and versatile for several uses, such as nanoparticle preparation for studies of tumor pathologies or scaffolds for tissue engineering in the field of regenerative medicine.
They are proposed as contrast agents for Field Cycling-MRI (FFC-MRI), a new technique that introduces the strength of the applied magnetic field as an entirely new dimension into MRI (Magnetic Resonance Imaging).

Possible Applications

• Low field NMR application, exploring the T1 dispersion behavior, a marker of deasese
• Assessment of pH-microenvironment for monitoring malignant pathlogies (diagnosis, treatment)
• Development of innovative biocompatible sensors for in vivo evaluation of tissue implants

Advantages

• Innovative action principle not based on the use of potentialy toxic metals, present in the clinical CA currently used
• Biocompatibility
• Simplicity of preparation and versatility
• Non invasive
• pH dependence of contrast, with important application in oncology and regenerative medicine