Effects of meso-tetrakis (4-sulfonatophenyl) porphyrin (TPPS4) aggregation on its spectral and kinetic characteristics and singlet oxygen production

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Vol. 261; p. 120063
• Main Authors: Parra, Gustavo G., Correa, Daniel S., Silveira-Alves, Eli, Almeida, Luciane M., Souza, Marcio A.R., De Boni, Leonardo, Misoguti, Lino, Mendonça, Cleber R., Zílio, Sérgio C., Barbosa Neto, Newton M., Borissevitch, Iouri E., Gonçalves, Pablo J.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.11.2021
• Subjects: Flash-photolysis; Photodynamic therapy; Photophysical characterization; Photothermal therapy; Singlet oxygen; Theranostics; Z-scan; Photothermal therapy; Photodynamic therapy; Singlet oxygen; Z-scan; Flash-photolysis; Photophysical characterization; Theranostics
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2021.120063

[Display omitted] •J-aggregates possess reverse saturable absorption in the whole spectral range studied.•Aggregation does not change the energy and electron transfer of triplet state.•The aggregates generate singlet oxygen and convert light energy into heat.•J-aggregates can be considered theranostic agents. The present work reports the effects of meso-tetrakis (4-sulfonatophenyl) porphyrin (TPPS4) aggregation on its excited states absorption spectra, triplet states quenching by molecular oxygen and singlet oxygen production. Experimental techniques such as optical absorption, Z-scan with a white light continuum source and the Laser Flash Photolysis were used to fulfil the study. J-aggregates possess reverse saturable absorption in the 505–660 nm spectral range with a peak centered close to 540 nm. These facts together with their fast relaxation time suggest that they can be employed as material for ultrafast optical limiting and switching. Even though aggregation reduces the porphyrin excited-state lifetimes and quantum yields, it does not reduce the probability of the contact between the quencher and the excited aggregate. Aggregation does not change the contribution of energy transfer mechanisms to triplet state quenching by molecular oxygen. The production of singlet oxygen, the intense absorption in the phototherapeutic window and the high efficiency of conversion of light energy into heat, allow consider J-aggregates as a theranostic agent for photomedicine. It is proposed to use J-aggregates for diagnostics by photoacoustic images and in combination with a near-infrared photodynamic/photothermal dual mode therapy, thus improving synergistically the therapeutic response.