title: Antibacterial and non-cytotoxic ultra-thin polyethylenimine film.
abstract: In recent years, a common strategy, to obtain more uniform and controlled synthesis of polyelectrolytes multilayers (PEMs), relies on a previous polyethylenimine (PEI) coating of the substrate surface. PEI is a synthetic cationic polymer which provides a positive charge distribution on the materials to be covered with PEMs. Despite being an important step, this pre-layer deposition is frequently overlooked and no comprehensive characterizations or deep discussions are reported in literature. In that sense, this work reports on the synthesis of a typical PEI film that works as a precursor for PEMs, and its detailed physicochemical characterization. As many PEMs are produced for antibacterial and biomedical applications, the cytotoxicity of the film was also tested using fibroblasts, and its antibacterial activity was studied using Staphylococcus aureus and Pseudomonas aeruginosa. Our results present the formation of an ultra-thin film of PEI with a thickness around 3.5nm, and with a significant percent of NH3+(35% of the total amount of N) in its chemical structure; NH3+is a key chemical group because it is considered an important bacterial killer agent. The film was stable and did not present important cytotoxic effect for fibroblasts up to 7days, contrary to other reports. Finally, the PEI film showed high antibacterial activity against the S. aureus strain: reductions in cell density were higher than 95% up to 24h.
authors.affiliation: Departamento de Física Aplicada, Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, 13083-859 Campinas, São Paulo, Brazil. Electronic address: jacobo@ifi.unicamp.br.
authors.forename: J
authors.initials: J
authors.lastname: Hernandez-Montelongo
authors.affiliation: Itibanyl Produtos Especiais LTDA, 13240-000 Jarinu, São Paulo, Brazil.
authors.forename: E G
authors.initials: EG
authors.lastname: Lucchesi
authors.affiliation: Faculdade de Engenharia Química, Universidade Estadual de Campinas, 13083-852 Campinas, São Paulo, Brazil.
authors.forename: V F
authors.initials: VF
authors.lastname: Nascimento
authors.affiliation: Faculdade de Engenharia Química, Universidade Estadual de Campinas, 13083-852 Campinas, São Paulo, Brazil.
authors.forename: C G
authors.initials: CG
authors.lastname: França
authors.affiliation: Centro de Desenvolvimento da Tecnologia Nuclear, 31270-901 Belo Horizonte, Mina Gerais, Brazil.
authors.forename: I
authors.initials: I
authors.lastname: Gonzalez
authors.affiliation: Centro de Desenvolvimento da Tecnologia Nuclear, 31270-901 Belo Horizonte, Mina Gerais, Brazil.
authors.forename: W A A
authors.initials: WAA
authors.lastname: Macedo
authors.affiliation: Laboratório de Biotecnologia, Instituto de Biologia, Universidade Estadual de Campinas, 13083-862 Campinas, São Paulo, Brazil.
authors.forename: D
authors.initials: D
authors.lastname: Machado
authors.affiliation: Laboratório de Biotecnologia, Instituto de Biologia, Universidade Estadual de Campinas, 13083-862 Campinas, São Paulo, Brazil.
authors.forename: M
authors.initials: M
authors.lastname: Lancellotti
authors.affiliation: Faculdade de Engenharia Química, Universidade Estadual de Campinas, 13083-852 Campinas, São Paulo, Brazil.
authors.forename: A M
authors.initials: AM
authors.lastname: Moraes
authors.affiliation: Faculdade de Engenharia Química, Universidade Estadual de Campinas, 13083-852 Campinas, São Paulo, Brazil.
authors.forename: M M
authors.initials: MM
authors.lastname: Beppu
authors.affiliation: Departamento de Física Aplicada, Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, 13083-859 Campinas, São Paulo, Brazil.
authors.forename: M A
authors.initials: MA
authors.lastname: Cotta
mesh_terms: D016475:3T3 Cells; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016923:Cell Death / Q000187:drug effects; D051379:Mice; D008807:Mice, Inbred BALB C; D018625:Microscopy, Atomic Force; D056951:Photoelectron Spectroscopy; D011094:Polyethyleneimine / Q000494:pharmacology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D013056:Spectrophotometry, Ultraviolet; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D011094:Polyethyleneimine
keywords: Antibacterial; Non-cytotoxic; Polyethylenimine; Ultra-thin film