Tuning Photodynamic Properties of BODIPY Dyes, Porphyrins’ Little Sisters

Abstract

The photodynamic properties of a series of non-halogenated, dibrominated and diiodinated BODIPYs with a phthalimido or amino end modification on the phenoxypentyl and phenoxyoctyl linker in the meso position were investigated. Halogen substitution substantially increased the singlet oxygen production based on the heavy atom effect. This increase was accompanied by a higher photodynamic activity against skin melanoma cancer cells SK-MEL-28, with the best compound reaching an EC50 = 0.052 ± 0.01 µM upon light activation. The dark toxicity (toxicity without light activation) of all studied dyes was not detected up to the solubility limit in cell culture medium (10 µM). All studied BODIPY derivatives were predominantly found in adiposomes (lipid droplets) with further lower signals colocalized in either endolysosomal vesicles or the endoplasmic reticulum. A detailed investigation of cell death indicated that the compounds act primarily through the induction of apoptosis. In conclusion, halogenation in the 2,6 position of BODIPY dyes is crucial for the efficient photodynamic activity of these photosensitizers.

Synthesis and Spectroscopic Properties of Selenophene[3, 2-b]-Fused BODIPYs

“…This may be beneficial to the generation of singlet oxygen. Green light (500–550 nm) prevents deep tissue damage to surrounding healthy cells caused by superficial skin tumors and is the best light source for PDT treatment of skin tumors. , 7 and 8 had almost the same absorption and emission peaks and the same low fluorescence quantum yield; we chose 7 as the representative of this type of dye. The singlet oxygen generation efficiencies were calculated with the 1 O 2 -specific capture agent of DPBF (1,3-diphenylisobenzofuran) under a green laser source (525 nm), and 8-phenyl-1,3,5,7-tetramethyl-2,6-bromo-BODIPY ( 2Br-BDP ) was chosen as a reference (Φ Δ = 0.31 in DCM) .…”

Combination of Two Photosensitisers in Anticancer, Antimicrobial and Upconversion Photodynamic Therapy

“…Together with their fluorescent properties that can be sufficiently retained, they become very interesting as possible theranostic agents [148,149]. The most common approach to improving ISC and 1 O 2 production is halogenation at the 2-and 6-positions, and although no BODIPY molecules have yet been approved for clinical trials, research into opening areas of application is continuing [150,151]. To improve the properties of both PDT and imaging, in some instances, BODIPY was prepared in a conjugate with porphyrin [152], or more commonly with phthalocyanines [153], and via the assembly of Pcs with conjugates of BODIPY and NPs such as nanodiamonds [154] and graphene quantum dots [155].…”

Structural alterations in cell organelles induced by photodynamic treatment with chlorin p6‐histamine conjugate in human oral carcinoma cells probed by 3D fluorescence microscopy

“…as reported for photofrin and cationic cycloimide derivatives of chlorin p 6 (Cp 6 ), respectively. [9][10][11][12] Whereas, the alterations in mitochondrial structure and function plays a central role in PDT-induced apoptosis which can be brought about directly if the photosensitizer localizes in mitochondria, [13,14] or indirectly when the photosensitizer localizes in other organelles such as endoplasmic reticulum (ER), Golgi apparatus (GA), and lysosomes involving complex crosstalk between damaged organelle and mitochondria. [15][16][17][18][19] Thus, to understand the role of various cell organelles in PDT-induced cell death, studies have been carried out by some investigators using electron microscopy where the PDT-induced structural alterations in the cell organelles have been characterized as generalized damage or swelling of cell organelles.…”