Improvement of Photodynamic Activity of Lipid–Membrane‐Incorporated Fullerene Derivative by Combination with a Photo‐Antenna Molecule

Abstract

The weak absorbance of pristine C , C , and fullerene derivatives at wavelengths over 600 nm hampers the use of these molecules as photosensitizers (PSs) for photodynamic therapy (PDT). The coexistence of light-harvesting antenna molecules with a fullerene derivative in lipid membrane bilayers solved this issue. By controlling the location of the C derivative in the lipid membrane, the liposomal dyad system for PDT improved the photodynamic activity via an efficient photoenergy transfer from antenna molecules to the fullerene derivative. The photodynamic activity was found to be much higher than those of dyad systems using pristine C and C .

Photodynamic Activity of Fullerene Derivatives Solubilized in Water by Natural‐Product‐Based Solubilizing Agents

“…By controlling the location of the C 60 derivatives in the liposomes by using ap olar substituent, [113] the dyad system is expected to achieve efficient photoenergy transfer between the C 60 derivative andD iD and to improve the photoinduced cytotoxicity. [116] Compound 2 was therefore employed as the photoactive molecule. The fluorescence quenching effect of LMI2-DiD (87 %) was much higher than those of LMIC 60 -DiD and LMIC 70 -DiD (55 and 59 %, respectively); this indicated that energy transfer occurred more efficiently from photoactivated DiD to 2,t han that to C 60 or C 70 .I nc ontrast, the fluorescenceq uenching effects of DiD in aqueous solution were compared with the g-CDx·C 60 and g-CDx·2 complexes in the absence of liposomes.…”

“…However, because C 60 , which exists near the center of the membrane bilayer, as mentioned in Section 3.4, keeps DiD at a distance, the positions are not optimal for energy transfer between C 60 and DiD. By controlling the location of the C 60 derivatives in the liposomes by using a polar substituent, the dyad system is expected to achieve efficient photoenergy transfer between the C 60 derivative and DiD and to improve the photoinduced cytotoxicity . Compound 2 was therefore employed as the photoactive molecule.…”

A Bio‐Conjugated Fullerene as a Subcellular‐Targeted and Multifaceted Phototheranostic Agent

“…This work fully elaborates the capabilities of fullerene@protein complexes as image‐guided PDT agents. As such complexes are highly adaptable, future work could aim at their functionalization both with tumor‐targeting tags to improve the cancer cell selectivity and promote the cellular uptake of the photosensitizing agent, [ 76 ] and with light‐harvesting molecular antennae [ 45,77–79 ] to improve both therapeutic efficiency and treatment depth in PDT.…”

Bacterial elimination via the photodynamic activity of a fullerene/light-harvesting antenna molecule assembled system integrated into liposome membranes

“…26 In particular, liposomal membranes are attractive platforms for designing and constructing assembled systems of fullerenes with dialkylated light-harvesting antenna molecules. [32][33][34] Previously, the poor absorption capacity of our photosensitizers over the longwavelength range between 600 and 700 nm was improved and the photoinduced cytotoxicity toward HeLa cells of these types of assembled systems was enhanced. Without the need for complicated synthesis of fullerenes, we used our system, which is based on LMI systems, to maximize and expand the availability of our photosensitizers at will by combining them with commercially available light-harvesting molecules.…”

“…The preparation and detailed characterization of the catC 60 / light-harvesting antenna molecule assembled system integrated into the liposomal membranes are reported elsewhere. 33 Briey, LMI-light-harvesting antenna molecules were prepared via a conventional freeze-thaw method using DMPC and dyes such as 1,1 0 -dioctadecyl-3,3,3 0 ,3 0 -tetramethylindocarbocyanine perchlorate (DiI; l max , 549 nm) and 1,1 0 -dioctadecyl-3,3,3 0 ,3 0tetramethylindodicarbocyanine (DiD; l max , 644 nm). Aerward, the catC 60 was introduced into the liposomal membranes via an exchange reaction 33 by mixing the catC 60 /g-cyclodextrin complex at 80 C, a temperature which is higher than the phase transition temperature of DMPC (DMPC, 1 mM; DiD or DiI, 0.025 mM; catC 60 , 0.05 mM).…”