title: Quantum dot effects upon the interaction between porphyrins and phospholipids in cell membrane models.
abstract: This study employed surface pressure isotherms and spectroscopic techniques to investigate the effect of quantum dots on the interaction between porphyrins and phospholipids using Langmuir monolayers and Langmuir-Blodgett films formed from negatively charged DMPA (the sodium salt of dimyristoyl-sn-glycero-phosphatidyl acid) and zwitterionic DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) as cell membrane models in the presence of 5,10,15,20-tetrakis(4-N-tetradecyl-pyridyl) porphyrin (TMPyP), 5,10,15,20-tetrakis(p-sulfonato-phenyl) porphyrin (TPPS4) and PEG-coated CdSe/ZnS quantum dots (QD). The porphyrins present at the monolayer subphase affected the organization of the lipids at the air/liquid interface, as shown by the changes in the surface pressure-surface area isotherms. QDs enhanced the interaction of TMPyP with DMPA, improving their transference from the liquid monolayers to solid supports. A higher amount of TMPyP was transferred to DMPA-Langmuir-Blodgett films when the QDs were present in the subphase as evidenced by the UV-Vis data. For DPPC the surface effects due to the presence of QDs are less evident.
authors.affiliation: Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, 14040-901, Brazil.|Department of Chemistry, Case Western Reserve University, Cleveland, OH, 44106-7078, USA.
authors.forename: Gustavo G
authors.initials: GG
authors.lastname: Parra
authors.affiliation: Estácio UNISEB- Centro Universitário, Ribeirão Preto, São Paulo, 14096-160, Brazil.
authors.forename: Galina
authors.initials: G
authors.lastname: Borissevitch
authors.affiliation: Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, 14040-901, Brazil.
authors.forename: Iouri
authors.initials: I
authors.lastname: Borissevitch
authors.affiliation: Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, 14040-901, Brazil. anapr@ffclrp.usp.br.
authors.forename: Ana P
authors.initials: AP
authors.lastname: Ramos
mesh_terms: D002462:Cell Membrane / Q000737:chemistry*; D010743:Phospholipids / Q000737:chemistry*; D011166:Porphyrins / Q000737:chemistry*; D045663:Quantum Dots / Q000737:chemistry*
chemical_list: D010743:Phospholipids; D011166:Porphyrins
keywords: Langmuir monolayers; Langmuir-Blodgett films; Porphyrin; Quantum dots