Physical Damage on Giant Vesicles Membrane as a Result of Methylene Blue Photoirradiation

Autor(es)

Mertins, Omar ^[1] ; Bacellar, Isabel O. L. ^[2] ; Thalmann, Fabrice ^[3] ; Marques, Carlos M. ^[3] ; Baptista, Mauricio S. ^[2] ; Itri, Rosangela ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Fis, Dept Fis Aplicada, BR-01498 Sao Paulo - Brazil

^[2] Univ Sao Paulo, Inst Quim, Dept Bioquim, BR-01498 Sao Paulo - Brazil

^[3] Univ Strasbourg, Inst Charles Sadron, CNRS, Strasbourg - France

• Tipo de documento: Artigo Científico
• Fonte: BIOPHYSICAL JOURNAL; v. 106, n. 1, p. 162-171, JAN 7 2014.
• Citações Web of Science: 28

Resumo

In this study we pursue a closer analysis of the photodamage promoted on giant unilamellar vesicles membranes made of dioleoyl-sn-glycero-3-phosphocholine (DOPC) or 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), by irradiating methylene blue present in the giant unilamellar vesicles solution. By means of optical microscopy and electro-deformation experiments, the physical damage on the vesicle membrane was followed and the phospholipids oxidation was evaluated in terms of changes in the membrane surface area and permeability. As expected, oxidation modifies structural characteristics of the phospholipids that lead to remarkable membrane alterations. By comparing DOPC- with POPC-made membranes, we observed that the rate of pore formation and vesicle degradation as a function of methylene blue concentration follows a diffusion law in the case of DOPC and a linear variation in the case of POPC. We attributed this scenario to the nucleation process of oxidized species following a diffusion-limited growth regime for DOPC and in the case of POPC a homogeneous nucleation process. On the basis of these premises, we constructed models based on reaction-diffusion equations that fit well with the experimental data. This information shows that the outcome of the photosensitization reactions is critically dependent on the type of lipid present in the membrane. (AU)

• Processo FAPESP: 10/18163-5 - Foto-proteção em membranas investigada pela técnica de microscopia óptica em vesículas unilamelares gigantes
• Beneficiário: Omar Mertins
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 12/50680-5 - Fotossensibilização nas ciências da vida
• Beneficiário: Mauricio da Silva Baptista
• Modalidade de apoio: Auxílio à Pesquisa - Temático