(Invited) C₆₀-Based Switchable Fluorescent Probes

Photodynamic therapy (PDT), an emerging non-invasive tumor treatment, requires suitable photosensitizer (PS) molecules that generate reactive oxygen species (ROSs) efficiently under long wavelength of light with deep tissue penetration, ideally activated in the diseased tissue. C 60 is known as an excellent acceptor molecule in both electron- and energy-transfer reactions and exhibits biocompatibility and efficient ROS generation, rendering it a promising candidate as a PS for PDT. In this study, we developed a C 60 -based dual-functional molecular probe containing a water-soluble C 60 -peptide and a donor fluorophore connected with a ligand peptide specific for matrix metalloproteinases (MMP) (Figure 1). We expect that such a molecular probe can be used in both diagnostic imaging and concurrent treatment. The probe revealed increased fluorescence signal and 1 O 2 generation in the presence of MMP2/9 enzymes that are known to be overexpressed in tumor cells. Furthermore, in vitro cellular tests demonstrated the probe's abilities in imaging MMP activity and photocytotoxicity on MMP-expressing tumor cells.