title: Effect of Solvent Choice on the Self-Assembly Properties of a Diphenylalanine Amphiphile Stabilized by an Ion Pair.
abstract: A diphenylalanine (FF) amphiphile blocked at the C terminus with a benzyl ester (OBzl) and stabilized at the N terminus with a trifluoroacetate (TFA) anion was synthetized and characterized. Aggregation of peptide molecules was studied by considering a peptide solution in an organic solvent and adding pure water, a KCl solution, or another organic solvent as co-solvent. The choice of the organic solvent and co-solvent and the solvent/co-solvent ratio allowed the mixture to be tuned by modulating the polarity, the ionic strength, and the peptide concentration. Differences in the properties of the media used to dissolve the peptides resulted in the formation of different self-assembled microstructures (e.g. fibers, branched-like structures, plates, and spherulites). Furthermore, crystals of TFA⋅FF-OBzl were obtained from the aqueous peptide solutions for X-ray diffraction analysis. The results revealed a hydrophilic core constituted by carboxylate (from TFA), ester, and amide groups, and the core was found to be surrounded by a hydrophobic crown with ten aromatic rings. This segregated organization explains the assemblies observed in the different solvent mixtures as a function of the environmental polarity, ionic strength, and peptide concentration.
authors.affiliation: Departament d'Enginyeria Química, Universitat Politècnica de Catalunya, EEBE, Edifici I.2, C/ Eduard Maristany, 10-14, 08019, Barcelona, Spain.|Barcelona Research Center for Multiscale Science and Engineering, Universitat Politècnica de Catalunya, C/ Eduard Maristany, 10-14, 08019, Barcelona, Spain.
authors.forename: Enric
authors.initials: E
authors.lastname: Mayans
authors.affiliation: Department of Organic Chemistry and Instituto de Síntesis Quimica y Catalisis Homogenea (ISQCH), University of Zaragoza-CSIC, 50009, Zaragoza, Spain.
authors.forename: Gema
authors.initials: G
authors.lastname: Ballano
authors.affiliation: Departament d'Enginyeria Química, Universitat Politècnica de Catalunya, EEBE, Edifici I.2, C/ Eduard Maristany, 10-14, 08019, Barcelona, Spain.|Barcelona Research Center for Multiscale Science and Engineering, Universitat Politècnica de Catalunya, C/ Eduard Maristany, 10-14, 08019, Barcelona, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Sendros
authors.affiliation: Departament de Mineralogia, Cristallografia i Depòsits Minerals, Universitat de Barcelona, Facultat de Geologia, c/Martí i Franquès, 0, 8028, Barcelona, Spain.|Unitat de Difracció de Raigs X, Centre Científic y Tecnològic, Universitat de Barcelona, C/Solé i Sabarís 1, 08028, Barcelona, Spain.
authors.forename: Merçè
authors.initials: M
authors.lastname: Font-Bardia
authors.affiliation: Departament d'Enginyeria Química, Universitat Politècnica de Catalunya, EEBE, Edifici I.2, C/ Eduard Maristany, 10-14, 08019, Barcelona, Spain.
authors.forename: J Lourdes
authors.initials: JL
authors.lastname: Campos
authors.affiliation: Departament d'Enginyeria Química, Universitat Politècnica de Catalunya, EEBE, Edifici I.2, C/ Eduard Maristany, 10-14, 08019, Barcelona, Spain.|Barcelona Research Center for Multiscale Science and Engineering, Universitat Politècnica de Catalunya, C/ Eduard Maristany, 10-14, 08019, Barcelona, Spain.
authors.forename: Jordi
authors.initials: J
authors.lastname: Puiggalí
authors.affiliation: Department of Organic Chemistry and Instituto de Síntesis Quimica y Catalisis Homogenea (ISQCH), University of Zaragoza-CSIC, 50009, Zaragoza, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Cativiela
authors.affiliation: Departament d'Enginyeria Química, Universitat Politècnica de Catalunya, EEBE, Edifici I.2, C/ Eduard Maristany, 10-14, 08019, Barcelona, Spain.|Barcelona Research Center for Multiscale Science and Engineering, Universitat Politècnica de Catalunya, C/ Eduard Maristany, 10-14, 08019, Barcelona, Spain.
authors.forename: Carlos
authors.identifier: http://orcid.org/0000-0003-4462-6075
authors.initials: C
authors.lastname: Alemán
mesh_terms: D004151:Dipeptides; D007477:Ions / Q000737:chemistry; D008968:Molecular Conformation; D010316:Particle Size; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry; D010649:Phenylalanine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013501:Surface-Active Agents / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D004151:Dipeptides; D007477:Ions; D010455:Peptides; D012997:Solvents; D013501:Surface-Active Agents; C026650:phenylalanylphenylalanine; D010649:Phenylalanine
keywords: fibers; hydrophilic core; nanostructures; peptide materials; stacking interactions