Photodynamic Therapy: Porphyrins and Phthalocyanines as Photosensitizers

Abstract

The present work is focussed on the principles of photodynamic therapy (PDT), emphasizing the photochemical mechanisms of reactive oxygen species formation and the consequent biochemical processes generated by the action of reactive oxygen species on various biological macromolecules and organelles. This paper also presents some of the most used photosensitizers, including Photofrin, and the new prototypes of photosensitizers, analysing their physicochemical and spectroscopic properties. At this point, the review discusses the therapeutic window of absorption of specific wavelengths involving first-and second-generation photosensitizers, as well as the principal light sources used in PDT. Additionally, the aggregation process, which consists in a phenomenon common to several photosensitizers, is studied. J-aggregates and H-aggregates are discussed, along with their spectroscopic effects. Most photosensitizers have a significant hydrophobic character; thus, the study of the types of aggregation in aqueous solvent is very relevant. Important aspects of the coordination chemistry of metalloporphyrins and metallophthalocyanines used as photosensitizers are also discussed. The state-of-the-art in PDT is evaluated, discussing recent articles in this area. Furthermore, macrocyclic photosensitizers, such as porphyrins and phthalocyanines, are specifically described. The present review is an important contribution, because PDT is one of the most auspicious advances in the therapy against cancer and other non-malignant diseases.

Photophysical and Thermodynamic Parameters of Hematoporphyrin in Solutions and Monolayers

“…The effectiveness of HP and its derivatives acting as photosensitizers is known to depend on the M. Kotkowiak · J. Łukasiewicz · A. Dudkowiak (B) Faculty of Technical Physics, Poznan University of Technology, Nieszawska 13a, 60-965 Poznan, Poland e-mail: alina.dudkowiak@put.poznan.pl aggregation form of the dye [5,6] and its localization in pathologically changed cells [7,8].…”

Synthesis and Isolation of 2,9,17,23-Tetrakis[(3,5-dimethyl-1H-pyrazol-1-yl)phenoxy]phthalocyanine and Its Magnesium(II) and Zinc(II) Complexes

“…Phthalocyanines are used as traditional dyes and pigments, [1,2] and, thanks to the unique physical and chemical properties, as photocatalysts, [3] semiconductor materials, [4,5] photosensitizers for photodynamic therapy of cancer, [6][7][8][9][10] materials of optoelectronics. [11] Substituted zinc and magnesium phthalocyanines have intensive red-visible region absorption with high extinction coefficient, both high singlet and triplet quantum yields and high singlet oxygen quantum yields.…”

Synthesis of β‐Pyrrolic‐Modified Porphyrins and Their Incorporation into DNA

“…Porphyrins are useful labels and have been widely studied in a variety of applications including in light-harvesting devices [2] and the production of reactive oxygen species. [3] The site-specific covalent attachment of porphyrin moieties to DNA has been achieved by using a variety of methodologies including the modification of nucleobases, [4][5][6][7][8][9] ribofuranose residues, [10][11][12][13][14][15] the phosphate backbone [16,17] and acyclic linkers. [18,19] Porphyrin moieties have been introduced as 3'-or 5'-molecular caps, [13,[19][20][21] as a nucleobase substituent in the middle of the helix [18] or as a label in the minor [11,17,22] and major [5][6][7][8][9] grooves.…”