Rotaxane probes for protease detection by ¹²⁹Xe hyperCEST NMR

Area of Science:

• Supramolecular Chemistry
• Chemical Biology
• Biomedical Imaging

Background:

• Matrix metalloproteinase 2 (MMP-2) is frequently overexpressed in cancerous tissues, making it a significant biomarker for cancer detection.
• Current methods for MMP-2 detection can be limited in sensitivity and specificity.
• Developing novel molecular tools for sensitive and specific MMP-2 detection is crucial for advancing cancer diagnostics.

Purpose of the Study:

• To develop a novel supramolecular system for the sensitive and specific detection of matrix metalloproteinase 2 (MMP-2) activity.
• To utilize ¹²⁹Xe hyperCEST NMR as a detection platform for protease activity.
• To create a protease-responsive molecular probe for potential cancer imaging applications.

Main Methods:

• Synthesis of a cyclobis(para-phenylene-22-crown-6) (CB6) based rotaxane incorporating a peptide substrate specific for MMP-2.
• Utilizing CB6-promoted click chemistry for the efficient synthesis of the rotaxane.
• Employing ¹²⁹Xe hyperCEST NMR spectroscopy to monitor the interaction of ¹²⁹Xe with the CB6 cage upon MMP-2 cleavage.

Main Results:

• Successful synthesis of the CB6 rotaxane with an embedded MMP-2 recognition sequence.
• Demonstration that MMP-2 enzymatic activity cleaves the rotaxane, releasing the CB6 cage.
• Observation of protease-responsive activation of ¹²⁹Xe@CB6 interactions, indicating successful detection of MMP-2 activity.

Conclusions:

• The developed CB6 rotaxane serves as an effective molecular probe for MMP-2 activity.
• ¹²⁹Xe hyperCEST NMR in conjunction with this rotaxane offers a sensitive method for detecting protease activity.
• This approach holds promise for the development of new diagnostic tools for cancer detection based on MMP-2 levels.