Structural and Photophysical Properties of Peptide Micro/Nanotubes Functionalized with Hypericin

Autor(es)

Souza, Marcia I. ^[1] ; Jaques, Ygor M. ^[1] ; de Andrade, Gislaine P. ^[1] ; Ribeiro, Anderson O. ^[1] ; da Silva, Emerson R. ^[1] ; Fileti, Eudes E. ^[2] ; Avilla, Erick de Souza ^[3] ; Pinheiro, Mauricio V. B. ^[3] ; Krambrock, Klaus ^[3] ; Alves, Wendel A. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed ABC, Ctr Ciencias Nat & Humanas, BR-09210170 Santo Andre, SP - Brazil

^[2] Univ Fed Sao Paulo, Inst Ciencia & Tecnol, BR-12231280 Sao Jose Dos Campos, SP - Brazil

^[3] Univ Fed Minas Gerais, ICEx, Dept Fis, BR-31270901 Belo Horizonte, MG - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Physical Chemistry B; v. 117, n. 9, p. 2605-2614, MAR 7 2013.
• Citações Web of Science: 22

Resumo

Hypericin is a photosensitizer with promising applications in photodynamic therapy (PDT) for cancer and infectious diseases treatments. Herein, we present a basic research study of L-diphenylalanine micro/nanotubes (FF-NTs) functionalized with hypericin. The system has special properties according to the hypericin concentration, with direct consequences on both morphological and photophysical behaviors. A clear dependence between the size of the tubes and the concentration of hypericin is revealed. The generation of reactive oxygen species (ROS) is found to be improved by similar to 57% in the presence of FF-NTs, as indirectly measured from the absorbance profile of 1,3-diphenylisobenzofuran (DPBF). In addition, when hypericin appears conjugated with FF-NTs, the characteristic fluorescence lifetime is significantly boosted, demonstrating the role of FF-NTs to enhance the photophysical properties and stabilizing the fluorophore in excited states. Electron paramagnetic resonance allows the proposition of a mechanism for the generation of ROS. Molecular dynamics simulations bring new insights into the interaction between hypericin and peptide assemblies, suggesting the spatial organization of the fluorophore onto the surface of the supramolecular structures as a key element to improve the photophysical properties reported here. (AU)

• Processo FAPESP: 08/53576-9 - Síntese, caracterização e estudo das propriedades eletrônicas dos nanotubos de peptídeos e óxido de titânio
• Beneficiário: Wendel Andrade Alves
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores
• Processo FAPESP: 08/57805-2 - Instituto de Bioanalítica
• Beneficiário: Lauro Tatsuo Kubota
• Modalidade de apoio: Auxílio à Pesquisa - Temático