Search

Your search keyword '"Hypercin incorporation"' showing total 2 results
Start Over Descriptor "Hypercin incorporation"
2 results on '"Hypercin incorporation"'

1. Mechanisms of hypericin incorporation to explain the photooxidation outcomes in phospholipid biomembrane models

Author

Lucas S.A. Pereira, Sabrina A. Camacho, Alexandre M. Almeida, Renato S. Gonçalves, Wilker Caetano, Christine DeWolf, Pedro H.B. Aoki, Universidade Estadual Paulista (UNESP), Universidade de São Paulo (USP), State University of Maringá, and Concordia University

Subjects
Anthracenes, Photosensitizing Agents, Surface Properties, Organic Chemistry, Cell Membrane, Static Electricity, Cell Biology, Hypercin incorporation, Biochemistry, Photodynamic therapy, Photooxidation, Molecular Biology, Perylene, Phospholipid biomembrane models, Phospholipids, MATERIAIS NANOESTRUTURADOS
Abstract

Made available in DSpace on 2022-04-28T19:51:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-05-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Natural Sciences and Engineering Research Council of Canada Cell membranes are the first barriers for drug binding and key for the action of photosensitizers (PS). Herein, we report on the incorporation of the PS hypericin into Langmuir monolayers of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1,2-dioleoyl-sn-glycero-3-phospho-L-serine (DOPS) to represent eukaryotic cell membranes, and 1,2-dioleoyl-sn-glycero-3-phospho(1’-rac-glycerol) (DOPG) to mimic bacterial membranes. Surface pressure (π) vs mean molecular area (Å) isotherms showed a high degree of interaction (binding, penetration and relative solubilization) of hypericin into DPPC and DOPC monolayers. On the other hand, electrostatic repulsions govern the interactions with DOPG and DOPS, favoring hypericin self-aggregation, as visualized by Brewster angle microscopy (BAM). Indeed, the larger domains in BAM were consistent with the greater expansion of DOPG monolayers with incorporated hypericin, owing to stronger electrostatic repulsions. In contrast to DPPC, light-irradiation of DOPC monolayers containing hypericin induced loss of material due to hydrocarbon chain cleavage triggered by contact-dependent reactions between triplet excited state of hypericin and chain unsaturations. The mild effects noted for both irradiated DOPS and DOPG monolayers are attributed to hypericin self-aggregation, which may have decreased the singlet oxygen quantum yield (Φ1O2) via self-quenching, despite the increased instability induced in the monolayers. São Paulo State University (UNESP) School of Sciences Humanities and Languages, SP São Carlos Institute of Physics University of São Paulo (USP) CP 369, SP Department of Chemistry State University of Maringá, PR Department of Chemistry and Biochemistry and Centre for NanoScience Research Concordia University São Paulo State University (UNESP) School of Sciences Humanities and Languages, SP FAPESP: 2018/08077–6 FAPESP: 2018/14692–5 FAPESP: 2018/16713–0 FAPESP: 2018/22214–6 CNPq: 403713/2016–1 Natural Sciences and Engineering Research Council of Canada: RGPIN-2019–07043

Published
2021

2. Mechanisms of hypericin incorporation to explain the photooxidation outcomes in phospholipid biomembrane models.

Author

Pereira, Lucas S.A., Camacho, Sabrina A., Almeida, Alexandre M., Gonçalves, Renato S., Caetano, Wilker, DeWolf, Christine, and Aoki, Pedro H.B.

Subjects
*HYPERICIN, *BACTERIAL cell membranes, *PHOTOOXIDATION, *BREWSTER'S angle, *BACTERIAL cell walls, *PHOTOCATALYTIC oxidation, *MONOMOLECULAR films
Abstract

Cell membranes are the first barriers for drug binding and key for the action of photosensitizers (PS). Herein, we report on the incorporation of the PS hypericin into Langmuir monolayers of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1,2-dioleoyl-sn-glycero-3-phospho- L -serine (DOPS) to represent eukaryotic cell membranes, and 1,2-dioleoyl-sn-glycero-3-phospho(1'-rac-glycerol) (DOPG) to mimic bacterial membranes. Surface pressure (π) vs mean molecular area (Å) isotherms showed a high degree of interaction (binding, penetration and relative solubilization) of hypericin into DPPC and DOPC monolayers. On the other hand, electrostatic repulsions govern the interactions with DOPG and DOPS, favoring hypericin self-aggregation, as visualized by Brewster angle microscopy (BAM). Indeed, the larger domains in BAM were consistent with the greater expansion of DOPG monolayers with incorporated hypericin, owing to stronger electrostatic repulsions. In contrast to DPPC, light-irradiation of DOPC monolayers containing hypericin induced loss of material due to hydrocarbon chain cleavage triggered by contact-dependent reactions between triplet excited state of hypericin and chain unsaturations. The mild effects noted for both irradiated DOPS and DOPG monolayers are attributed to hypericin self-aggregation, which may have decreased the singlet oxygen quantum yield (Φ1O 2) via self-quenching, despite the increased instability induced in the monolayers. • Incorporation of hypericin into mimetic eukaryotic and bacterial cell membranes. • High penetration and interaction of hypericin into phosphatidylcholines' monolayers. • Hypericin aggregates due to electrostatic repulsions with DOPG and DOPS monolayers. • Irradiation of DOPC:hypercin triggers chain cleavage by contact-dependent reactions. [ABSTRACT FROM AUTHOR]

Published
2022
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results