Synthesis and photophysical studies of a chlorin sterically designed to prevent self-aggregation

Assis, Francisco F. de; Souza, Juliana M. de; Assis, Beatriz H. K.; Brocksom, Timothy J.; Oliveira, Kléber T. de

doi:10.1016/j.dyepig.2013.02.011

Cited by 23 publications

(11 citation statements)

References 21 publications

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“…Several recent papers have reported on different approaches in order to control PS aggregation. New PS molecules less prone to aggregate were designed with chemical groups that have weak intermolecular interactions or that are bulkier avoiding aggregation by steric effect (Uchoa et al, 2011 ; de Assis et al, 2013 ; dos Santos et al, 2013 ). However, once in the biological media, interactions of PS with biomolecules or with membranes may alter the monomer/aggregate equilibrium (Junqueira et al, 2002 ; Severino et al, 2003 ; Gabrielli et al, 2004 ).…”

Section: Photosensitizing Nps With Controlled Ps Aggregationmentioning

confidence: 99%

Photosensitizing nanoparticles and the modulation of ROS generation

Tada

Baptista

2015

Front. Chem.

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The association of PhotoSensitizer (PS) molecules with nanoparticles (NPs) forming photosensitizing NPs, has emerged as a therapeutic strategy to improve PS tumor targeting, to protect PS from deactivation reactions and to enhance both PS solubility and circulation time. Since association with NPs usually alters PS photophysical and photochemical properties, photosensitizing NPs are an important tool to modulate ROS generation. Depending on the design of the photosensitizing NP, i.e., type of PS, the NP material and the method applied for the construction of the photosensitizing NP, the deactivation routes of the excited state can be controlled, allowing the generation of either singlet oxygen or other reactive oxygen species (ROS). Controlling the type of generated ROS is desirable not only in biomedical applications, as in Photodynamic Therapy where the type of ROS affects therapeutic efficiency, but also in other technological relevant fields like energy conversion, where the electron and energy transfer processes are necessary to increase the efficiency of photoconversion cells. The current review highlights some of the recent developments in the design of Photosensitizing NPs aimed at modulating the primary photochemical events after light absorption.

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Section: Photosensitizing Nps With Controlled Ps Aggregationmentioning

confidence: 99%

Photosensitizing nanoparticles and the modulation of ROS generation

Tada

Baptista

2015

Front. Chem.

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“…10,11 The chemistry of porphyrins, chlorins and their derivatives has been extensively studied since the discovery of their potential application as PSs in photodynamic therapy. [12][13][14] Some PSs can be easily prepared by semi-synthesis using abundant natural starting materials, such as the chlorophylls. The use of natural pigments is well recommended, and one of the main reasons is their lower cost when compared to the synthetic PSs.…”

Section: Introductionmentioning

confidence: 99%

Photobiological characteristics of chlorophyll a derivatives as microbial PDT agents

Uliana

Pires

Pratavieira

et al. 2014

Photochem Photobiol Sci

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a Chlorin-e6 (chl-e6) and a hydrogenated derivative (chl-e6H) were semi-synthesized, and their photophysical properties and photodynamic activity against Escherichia coli, Staphylococcus aureus and Candida albicans evaluated. Methyl pheophorbide-a (Mepheo-a) was obtained from S. maxima using methanolic extraction with acid catalysis (CH 3 OH-H 2 SO 4 ). Chlorin-e6 was prepared from Mepheo-a by basic hydrolysis with H 2 O-acetone and NaOH. Hydrogenated Chlorin-e6 was synthesized by a similar procedure starting from the hydrogenated methyl pheophorbide-a (Mepheo-aH). Photophysical studies were performed in order to determine the singlet oxygen quantum yield of chl-e6H which is higher than that of chl-e6. The microorganism inactivation of chl-e6 and chl-e6H was investigated at two concentrations and three fluence levels. Both chl-e6 and chl-e6H showed microorganism inactivation against Gram-positive bacteria and a fungus.

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“…Other measurements such as singlet oxygen production, fluorescence yield, and photo degradation studies were also performed, providing good results as demonstrated in our recent publication in Dyes and Pigments. 2 …”

Section: Resultsmentioning

confidence: 99%

“…In this work, we have prepared a new chlorin derivative which is self-prevented from aggregation, by a 1,3-dipolar cycloaddition between a very activated porphyrin (dipolarophile) and a benzyl azomethine ylide. 2 We have also performed some preliminary photophysical studies in order to evaluate its ability to act as a photosensitizer in PDT.…”

Section: Introductionmentioning

confidence: 99%