Scientific Reports (Aug 2023)

4-Amino-TEMPO loaded liposomes as sensitive EPR and OMRI probes for the detection of phospholipase A2 activity

  • Diego Alberti,
  • Eric Thiaudiere,
  • Elodie Parzy,
  • Sabrina Elkhanoufi,
  • Sahar Rakhshan,
  • Rachele Stefania,
  • Philippe Massot,
  • Philippe Mellet,
  • Silvio Aime,
  • Simonetta Geninatti Crich

DOI
https://doi.org/10.1038/s41598-023-40857-4
Journal volume & issue
Vol. 13, no. 1
pp. 1 – 10

Abstract

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Abstract This work aims at developing a diagnostic method based on Electron Paramagnetic Resonance (EPR) measurements of stable nitroxide radicals released from “EPR silent” liposomes. The liposome destabilisation and consequent radical release is enzymatically triggered by the action of phospholipase A2 (PLA2) present in the biological sample of interest. PLA2 are involved in a broad range of processes, and changes in their activity may be considered as a unique valuable biomarker for early diagnoses. The minimum amount of PLA2 measured “in vitro” was 0.09 U/mL. Moreover, the liposomes were successfully used to perform Overhauser-enhanced Magnetic Resonance Imaging (OMRI) in vitro at 0.2 T. The amount of radicals released by PLA2 driven liposome destabilization was sufficient to generate a well detectable contrast enhancement in the corresponding OMRI image.