pH-triggered formation of nanoribbons from yeast-derived glycolipid biosurfactants
作者:Anne-Sophie Cuvier、Jan Berton、Christian V. Stevens、Giulia C. Fadda、Florence Babonneau、Inge N. A. Van Bogaert、Wim Soetaert、Gérard Pehau-Arnaudet、Niki Baccile
DOI:10.1039/c4sm00111g
日期:——
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 1H–1H through-space correlations via Nuclear Magnetic Resonance under very fast (67 kHz) Magic Angle Spinning (MAS-NMR).
在本文中,我们表明,饱和形式的酸性槐糖脂(工业规模化的 bolaform 微生物糖脂家族)仅在 pH 值低于 7.5 时才意外地形成手性纳米纤维。我们特别说明了这种现象源于分子手性、氢键、范德华力和空间位阻的微妙协同效应。 pH 响应行为通过动态光散射 (DLS)、pH 滴定和场发射扫描电子显微镜 (FE-SEM) 显示,而纳米级手性通过圆二色性 (CD) 和冷冻透射电子显微镜 (cryo-TEM) 证明)。使用小角中子散射 (SANS)、广角 X 射线散射 (WAXS) 和 2D 1H–1H 空间相关性(通过极快 (67 kHz) 魔角旋转下的核磁共振)研究了带内槐糖脂的堆积(MAS-NMR)。