Binding of Methylene Blue onto Langmuir Mono layers Representing Cell Membranes May Explain Its Efficiency as Photosensitizer in Photodynamic Therapy

Autor(es)

Schmidt, Thais F. ^[1] ; Caseli, Luciano ^[2] ; Oliveira, Jr., Osvaldo N. ^[3] ; Itri, Rosangela ^[4]

Afiliação do(s) autor(es)

^[1] Fed Univ ABC UFABC, BR-09210580 Santo Andre, SP - Brazil

^[2] Univ Fed Sao Paulo, Inst Environm Chem & Pharmaceut Sci, BR-09913030 Diadema, SP - Brazil

^[3] Univ Sao Paulo, Sao Carlos Inst Phys, BR-13560970 Sao Carlos, SP - Brazil

^[4] Univ Sao Paulo, Inst Phys, BR-05508090 Sao Paulo, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Langmuir; v. 31, n. 14, p. 4205-4212, APR 14 2015.
• Citações Web of Science: 16

Resumo

We provide evidence for the electrostatic interactions between the cationic photosensitizer methylene blue (MB) and cell membrane models represented by neat and mixed Langmuir monolayers of dioleylphosphatidylcholine (DOPC) and 1,1',2,2'-tetraoleoylcardiolipin (CL). From surface pressure measurements, MB was found to adsorb strongly and expand CL-containing monolayers, while it caused an apparent decreasing in molecular area on neat DOPC monolayer. The binding site of MB could be inferred from data with the surface-specific polarization-modulated infrared reflectionabsorption spectroscopy (PM-IRRAS) technique, where changes induced by MB were observed in the vibrational modes of the phosphate groups of both CL and DOPC. The incorporation of MB also affected the carbonyl groups and the packing of the alkyl chains, thus indicating that MB binding site favors singlet oxygen generation close to the double bonds in the alkyl chains, an important requirement for photodynamic efficiency. Significantly, the data presented here demonstrate that MB may act in membranes composed by PCs, such as mammalian plasma membranes, and in those containing CL, as in bacterial and inner mitochondrial membranes. (AU)

• Processo FAPESP: 08/07240-9 - Monocamadas e bicamadas lipídicas: adsorção de azul de metileno e fotossensibilização
• Beneficiário: Thaís Fernandes Schmidt
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 12/50680-5 - Fotossensibilização nas ciências da vida
• Beneficiário: Mauricio da Silva Baptista
• Modalidade de apoio: Auxílio à Pesquisa - Temático