title: pH-triggered formation of nanoribbons from yeast-derived glycolipid biosurfactants.
abstract: In the present paper, we show that the saturated form of acidic sophorolipids, a family of industrially scaled bolaform microbial glycolipids, unexpectedly forms chiral nanofibers only at pH below 7.5. In particular, we illustrate that this phenomenon derives from a subtle cooperative effect of molecular chirality, hydrogen bonding, van der Waals forces and steric hindrance. The pH-responsive behaviour was shown by Dynamic Light Scattering (DLS), pH-titration and Field Emission Scanning Electron Microscopy (FE-SEM) while the nanoscale chirality was evidenced by Circular Dichroism (CD) and cryo Transmission Electron Microscopy (cryo-TEM). The packing of sophorolipids within the ribbons was studied using Small Angle Neutron Scattering (SANS), Wide Angle X-ray Scattering (WAXS) and 2D (1)H-(1)H through-space correlations via Nuclear Magnetic Resonance under very fast (67 kHz) Magic Angle Spinning (MAS-NMR).
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, UMR 7574, Chimie de la Matière Condensée de Paris, F-75005, Paris, France. niki.baccile@upmc.fr.
authors.forename: Anne-Sophie
authors.initials: AS
authors.lastname: Cuvier
authors.forename: Jan
authors.initials: J
authors.lastname: Berton
authors.forename: Christian V
authors.initials: CV
authors.lastname: Stevens
authors.forename: Giulia C
authors.initials: GC
authors.lastname: Fadda
authors.forename: Florence
authors.initials: F
authors.lastname: Babonneau
authors.forename: Inge N A
authors.initials: IN
authors.lastname: Van Bogaert
authors.forename: Wim
authors.initials: W
authors.lastname: Soetaert
authors.forename: Gérard
authors.initials: G
authors.lastname: Pehau-Arnaudet
authors.forename: Niki
authors.initials: N
authors.lastname: Baccile
mesh_terms: D002942:Circular Dichroism; D006017:Glycolipids / Q000737:chemistry* / Q000378:metabolism; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D008968:Molecular Conformation; D057139:Nanofibers / Q000737:chemistry; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D055672:Static Electricity; D013237:Stereoisomerism; D013501:Surface-Active Agents / Q000737:chemistry / Q000378:metabolism
chemical_list: D006017:Glycolipids; D037742:Nanotubes, Carbon; D013501:Surface-Active Agents