Speaker
Description
Lanthanide Luminescent Bioprobes (LLBs) exploit the pecular properties of lanthanides such as sharp and intense emission band spread from the visible to the Near Infra-Red (NIR) and long luminescent lifetimes (up to ms for Eu and Tb), which make them useful tools for time-resolved optical imaging. Structurally, LLBs consist in lanthanide chelates functionalized with a chromophore in charge of sensitizing the metal centre. Polyazacycloalcanes are well known to form highly stable metal complexes. Among them, due to the rigidity brought by its pyridine unit, pyclen has emerged as an interesting platform and was studied in our group to developed Ln3+ complexes with great photophysical properties under one-photon excitation. However, UV-excitation limits the potential of these bioprobes because of its poor penetration in tissues. We will present here the conception of new generations of LLBs (Figure 1) exploiting the advantages of two-photon excitation (biological transparency windows, high resolution). Indeed, functionalization of pyclen with π-conjugated antennas led to LLBs with astonishing emissive properties. Cell imaging was successful thanks to the high brightness of the bioprobes, even with both excitation and detection in the NIR channel. Imaging studies performed on Zebrafish also demonstrated the potential of these LLBs for in vivo imaging. We then confirmed that the introduction of a coupling function on the pyclen skeleton for further targeting preserves the photophysical properties of the bioprobes.
