title: Layer-by-layer films containing peptides of the Cry1Ab16 toxin from Bacillus thuringiensis for potential biotechnological applications.
abstract: Cry1Ab16 is a toxin of crystalline insecticidal proteins that has been widely used in genetically modified organisms (GMOs) to gain resistance to pests. For the first time, in this study, peptides derived from the immunogenic Cry1Ab16 toxin (from Bacillus thuringiensis) were immobilized as layer-by-layer (LbL) films. Given the concern about food and environmental safety, a peptide with immunogenic potential, PcL342-354C, was selected for characterization of the electrochemical, optical, and morphological properties. The results obtained by cyclic voltammetry (CV) showed that the peptide have an irreversible oxidation process in electrolyte of 0.1 mol · L(-1) potassium phosphate buffer (PBS) at pH7.2. It was also observed that the electrochemical response of the peptide is governed mainly by charge transfer. In an attempt to maximize the electrochemical signal of peptide, it was intercalated with natural (agar, alginate and chitosan) or synthetic polymers (polyethylenimine (PEI) and poly(sodium 4-styrenesulfonate (PSS)). The presence of synthetic polymers on the film increased the electrochemical signal of PcL342-354C up to 100 times. Images by Atomic Force Microscopy (AFM) showed that the immobilized PcL342-354C formed self-assembled nanofibers with diameters ranging from 100 to 200 nm on the polymeric film. By UV-Visible spectroscopy (UV-Vis) it was observed that the ITO/PEI/PSS/PcL342-354C film grows linearly up to the fifth layer, thereafter tending to saturation. X-ray diffraction confirmed the presence on the films of crystalline ITO and amorphous polypeptide phases. In general, the ITO/PEI/PSS/PcL342-354C film characterization proved that this system is an excellent candidate for applications in electrochemical sensors and other biotechnological applications for GMOs and environmental indicators.
authors.affiliation: REQUIMTE/LAQV, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Rua Dr. António Bernardino de Almeida, 431, 4200-072 Porto, Portugal.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Plácido
authors.affiliation: Núcleo de Pesquisa em Biodiversidade e Biotecnologia, BIOTEC, Campus Ministro Reis Velloso, CMRV, Universidade Federal do Piauí, UFPI, 64202020 Parnaíba, Piaui, Brazil.
authors.forename: Emanuel Airton
authors.initials: EA
authors.lastname: de Oliveira Farias
authors.affiliation: IPEEC-CENPAT-CONICET, Centro Nacional Patagónico, Consejo Nacional de Investigaciones Científicas y Técnicas, 9120 Puerto Madryn, Chubut, Argentina.
authors.forename: Mariela M
authors.initials: MM
authors.lastname: Marani
authors.affiliation: Núcleo de Pesquisa em Biodiversidade e Biotecnologia, BIOTEC, Campus Ministro Reis Velloso, CMRV, Universidade Federal do Piauí, UFPI, 64202020 Parnaíba, Piaui, Brazil.
authors.forename: Andreanne G
authors.initials: AG
authors.lastname: Vasconcelos
authors.affiliation: Instituto de Física de São Carlos, Universidade de São Paulo, USP, 13566-590 São Carlos, SP, Brazil.
authors.forename: Ana C
authors.initials: AC
authors.lastname: Mafud
authors.affiliation: Instituto de Física de São Carlos, Universidade de São Paulo, USP, 13566-590 São Carlos, SP, Brazil.
authors.forename: Yvonne P
authors.initials: YP
authors.lastname: Mascarenhas
authors.affiliation: Núcleo de Pesquisa em Biodiversidade e Biotecnologia, BIOTEC, Campus Ministro Reis Velloso, CMRV, Universidade Federal do Piauí, UFPI, 64202020 Parnaíba, Piaui, Brazil; Laboratório de Materiais Avançados, LIMAV, Engenharia de Materiais, Centro de Tecnologia, CT, Universidade Federal do Piauí, UFPI, 64049550 Teresina, Piaui, Brazil.
authors.forename: Carla
authors.initials: C
authors.lastname: Eiras
authors.affiliation: Núcleo de Pesquisa em Biodiversidade e Biotecnologia, BIOTEC, Campus Ministro Reis Velloso, CMRV, Universidade Federal do Piauí, UFPI, 64202020 Parnaíba, Piaui, Brazil. Electronic address: jrsaleite@gmail.com.
authors.forename: José R S A
authors.initials: JR
authors.lastname: Leite
authors.affiliation: REQUIMTE/LAQV, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Rua Dr. António Bernardino de Almeida, 431, 4200-072 Porto, Portugal.
authors.forename: Cristina
authors.initials: C
authors.lastname: Delerue-Matos
mesh_terms: D000464:Alginates / Q000737:chemistry; D001413:Bacillus thuringiensis / Q000378:metabolism*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D048271:Chitosan / Q000737:chemistry; D002942:Circular Dichroism; D055664:Electrochemical Techniques; D004731:Endotoxins / Q000737:chemistry* / Q000378:metabolism; D020723:Glucuronic Acid / Q000737:chemistry; D006460:Hemolysin Proteins / Q000737:chemistry* / Q000378:metabolism; D006603:Hexuronic Acids / Q000737:chemistry; D018625:Microscopy, Atomic Force; D057139:Nanofibers / Q000737:chemistry; D010084:Oxidation-Reduction; D010455:Peptides / Q000737:chemistry*; D011094:Polyethyleneimine / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D017971:Tin Compounds / Q000737:chemistry
chemical_list: D000464:Alginates; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; D006603:Hexuronic Acids; D010455:Peptides; D017971:Tin Compounds; C030956:insecticidal crystal protein, Bacillus Thuringiensis; C109984:indium tin oxide; D020723:Glucuronic Acid; D011094:Polyethyleneimine; D048271:Chitosan
keywords: Bioelectrochemistry; Cry1Ab16 toxin; Genetically modified organism; Layer-by-layer film