Hybrid photoactive fullerene derivative–ruboxyl nanostructures for photodynamic therapy

Abstract

Here we report the investigation of photophysical properties and photodynamic action of two novel water soluble hybrid molecular structures based on [60]fullerene dyads bearing covalently attached residues of anthracycline antibiotic "ruboxyl". Molecular structures of the designed compounds were confirmed by IR and UV-VIS absorption spectroscopy, electrospray mass spectrometry (compound 5), and (1)H and (13)C NMR spectroscopy. Dynamic light scattering, steady-state and kinetic fluorimetry and UV-VIS absorption spectroscopy techniques were used to study the behavior of the synthesized hybrid molecular structures in aqueous solutions. Photodynamic activity of the compounds was evaluated by monitoring the O2(-) generation under visible light irradiation using the NBT test. It has been shown that the anthracycline chromophore (ruboxyl moiety possesses no photodynamic activity) behaves as an efficient photosensitizer for the fullerene core operating via the energy and/or the electron transfer pathways. The presented approach opens up wide opportunities for the design of various fullerene-based donor-acceptor systems with enhanced photodynamic properties potentially suitable for biomedicinal applications.

Enhancing Type I Photochemistry in Photodynamic Therapy Under Near Infrared Light by Using Antennae–Fullerene Complexes

“…Kotelnikov et al reported that as an antenna for fullerene, ruboxyl, with a luminescence band at 590 nm, had two mechanisms for fluorescence quenching, namely, Förster energy transfer and photo‐induced electron transfer (Fig. E and F) .…”

“…On the one hand, A* could transfer energy to PS to form A‐ 3 PS* , which can react with O 2 and form O 2 − and 1 O 2 via the type I and II pathways, respectively. The specific energy transfer varies depending on the antenna and PS, but 3 PS* is always a by‐product of the photo‐induced energy transfer process . On the other hand, A* could transfer electrons to PS to form A •+ ‐PS •− , and the PS •− of this radical ion pair leads to the efficient generation of O 2 − via the type I pathway .…”

Pyropheophorbide-Fullerene Dyad: Synthesis and Photochemical Properties

“…The creation of highly efficient photosensitizers that generate ROS by pathway I is of considerable interest since it is expected that they should be more effective in some cases, for example, against hypoxic tumors. [7] We have previously created dyads based on fullerene and dyes fluorescein, [8] ruboxyl [9] and chlorin, [10] which showed the high efficiency of ROS generation. For example, a tenfold increase in the superoxide generation efficiency by a fullerene-chlorin dyad in an aqueous solution (compared to a free chlorin) was shown.…”

Molekulare Halbleiter‐Tenside mit Fullerenol‐Kopfgruppe und Farbstoffketten für die photokatalytische Umwandlung von Kohlenstoffdioxid

“…Abbildung b,c zeigt einen vorgeschlagenen Mechanismus für diesen Prozess . Wir gehen davon aus, dass der allgemeine Mechanismus dem der photokatalytischen Superoxidproduktion von Fullerenen und Fullerenolen ähnlich ist, bei der das Fullerenol Elektronen überträgt . Die Reduzierbarkeit der Fullerenolverbidung hängt stark vom Grad der Polyhydroxylierung und der Art der Polyhydroxylierungseinheiten ab und kann zwischen einem leicht negativen und einem positiven Potential variieren, während eine stärkere Reduktionsfähigkeit aus einer größeren π‐Elektronenstabilisierung resultiert .…”