title: Effective protection of biological membranes against photo-oxidative damage: Polymeric antioxidant forming a protecting shield over the membrane.
abstract: We have prepared a chitosan polymer modified with gallic acid in order to develop an efficient protection strategy biological membranes against photodamage. Lipid bilayers were challenged with photoinduced damage by photosensitization with methylene blue, which usually causes formation of hydroperoxides, increasing area per lipid, and afterwards allowing leakage of internal materials. The damage was delayed by a solution of gallic acid in a concentration dependent manner, but further suppressed by the polymer at very low concentrations. The membrane of giant unilamellar vesicles was covered with this modified macromolecule leading to a powerful shield against singlet oxygen and thus effectively protecting the lipid membrane from oxidative stress. The results have proven the discovery of a promising strategy for photo protection of biological membranes.
authors.affiliation: Department of Biophysics, Escola Paulista de Medicina, Universidade Federal de São Paulo, Rua Botucatu 862, 04023-062 São Paulo, Brazil; Applied Physics Department, Institute of Physics, University of São Paulo, Rua do Matão, Travessa R 187, 05508-900 São Paulo, Brazil. Electronic address: mertins@unifesp.br.
authors.forename: Omar
authors.initials: O
authors.lastname: Mertins
authors.affiliation: Department of Biophysics, Escola Paulista de Medicina, Universidade Federal de São Paulo, Rua Botucatu 862, 04023-062 São Paulo, Brazil.
authors.forename: Patrick D
authors.initials: PD
authors.lastname: Mathews
authors.affiliation: Applied Physics Department, Institute of Physics, University of São Paulo, Rua do Matão, Travessa R 187, 05508-900 São Paulo, Brazil.
authors.forename: Andreza B
authors.initials: AB
authors.lastname: Gomide
authors.affiliation: Department of Biochemistry, Institute of Chemistry, University of São Paulo, Avenida Prof. Lineu Prestes 748, 05508-900 São Paulo, Brazil.
authors.forename: Mauricio S
authors.initials: MS
authors.lastname: Baptista
authors.affiliation: Applied Physics Department, Institute of Physics, University of São Paulo, Rua do Matão, Travessa R 187, 05508-900 São Paulo, Brazil. Electronic address: itri@if.usp.br.
authors.forename: Rosangela
authors.initials: R
authors.lastname: Itri
mesh_terms: D000975:Antioxidants / Q000138:chemical synthesis* / Q000528:radiation effects; D002462:Cell Membrane / Q000737:chemistry / Q000528:radiation effects; D048271:Chitosan / Q000737:chemistry* / Q000528:radiation effects; D020099:Coated Materials, Biocompatible / Q000138:chemical synthesis* / Q000528:radiation effects; D005707:Gallic Acid / Q000737:chemistry*; D008027:Light; D008422:Materials Testing; D010084:Oxidation-Reduction / Q000528:radiation effects; D010100:Oxygen / Q000737:chemistry; D011837:Radiation-Protective Agents / Q000737:chemistry* / Q000528:radiation effects; D053835:Unilamellar Liposomes / Q000737:chemistry* / Q000528:radiation effects
chemical_list: D000975:Antioxidants; D020099:Coated Materials, Biocompatible; D011837:Radiation-Protective Agents; D053835:Unilamellar Liposomes; D005707:Gallic Acid; D048271:Chitosan; D010100:Oxygen
keywords: Biomaterial; Biomembrane; Biopolymer; Giant vesicles; Photo-protection; Polymer shield