Functionalized 129Xe contrast agents for magnetic resonance imaging

Area of Science:

• Biomedical Engineering
• Molecular Imaging
• Magnetic Resonance Imaging

Background:

• The concept of xenon biosensors for MRI was introduced in 2001.
• Early work demonstrated hyperpolarized 129Xe bound to cryptophane can detect streptavidin at nM-microM concentrations.

Purpose of the Study:

• To review recent developments in xenon biosensor technology for molecular imaging.
• To highlight advancements addressing challenges in sensitivity and target localization.

Main Methods:

• Synthesis of cryptophanes with enhanced xenon affinity and distinct 129Xe magnetic resonance spectra.
• Development of dendrimeric cryptophane assemblies and inorganic zeolites for targeted xenon localization.
• Design of biosensors detecting changes in 129Xe chemical shift based on biomolecular activity.

Main Results:

• New cryptophanes show 10-fold higher xenon affinity.
• Dendrimeric assemblies and zeolites enable localization of xenon to rare targets.
• Biosensors demonstrate measurable 129Xe chemical shift changes in response to biomolecules.

Conclusions:

• Xenon biosensors have significantly advanced for molecular imaging.
• These developments enable sensitive detection and localization of targets, including initial cell studies.
• Future applications include detecting oligonucleotides, proteins, and enzyme activity via MRI.