Metallacrowns could well revolutionize medical imaging and non-invasive diagnosis. This is what scientists from the CNRS show in an article published in the journal
Chemical Science, where they present these new biological imaging agents.
For years, scientists have been interested in lanthanides, these "rare earth" elements capable of emitting an intense and characteristic light in the near-infrared range. Inserted into supramolecular complexes called metallacrowns, they seemed perfect for non-invasive optical biological imaging, including deep tissues and not just superficial ones. Their major problem: they had to be excited using ultraviolet rays, a light source that is aggressive to tissues, which severely limits their use in biology and medicine.
Near-infrared luminescence image superimposed on the white light image obtained on living HeLa cells in which the lanthanide-metallacrowns, whose structure appears as an inset, were incubated.
@Timothée Lathion The team of scientists from the Centre de biophysique moléculaire (CNRS) has now managed to overcome this limitation. They have designed a new family of metallacrowns whose innovative structure incorporates, on their periphery, small biocompatible organic sensitizers called "coumarins". These "antennas" capture visible light, which is harmless to biological systems, and efficiently transfer it to the lanthanide, which then re-emits in the second near-infrared window (NIR-II). This spectral range is ideal for imaging, as this type of light penetrates deep into tissues with very little scattering.
Thanks to this innovative approach, the researchers were able to use this coumarin-integrated metallacrown to label living cells and visualize them using near-infrared microscopy. The images obtained show a stable light signal, offering good detection sensitivity, confirming the robustness of this new generation of imaging probes.
These results mark a key step: they transform a long-promising tool, previously limited by UV excitation, into a technology now compatible with real biological imaging. In the long run, these luminous crowns could become valuable allies for deep observation of living tissues, improving early diagnosis, or monitoring disease progression. A breakthrough published in
Chemical Science that paves the way for a vast field of non-invasive imaging
in vitro and
in vivo.
Editor: AVR