Palmitic acid sophorolipid biosurfactant: from self-assembled fibrillar network (SAFiN) to hydrogels with fast recovery

DOI: 10.1098/rsta.2020.0343

Authors: Niki Baccile (Sorbonne Université) , Ghazi Ben Messaoud (Sorbonne Université) , Patrick Le Griel (Sorbonne Université) , Nathan Cowieson (Diamond Light Source) , Javier Perez (Synchrotron Soleil) , Robin Geys (Ghent University) , Marilyn De Graeve (Ghent University) , Sophie L. K. W. Roelants (Ghent University) , Wim Soetaert (Ghent University; Bio Base Europe Pilot Plant)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Philosophical Transactions Of The Royal Society A: Mathematical, Physical And Engineering Sciences , VOL 379

State: Published (Approved)
Published: September 2021
Diamond Proposal Number(s): 23247

Abstract: Nanofibres are an interesting phase into which amphiphilic molecules can self-assemble. Described for a large number of synthetic lipids, they were seldom reported for natural lipids like microbial amphiphiles, known as biosurfactants. In this work, we show that the palmitic acid congener of sophorolipids (SLC16:0), one of the most studied families of biosurfactants, spontaneously forms a self-assembled fibre network (SAFiN) at pH below 6 through a pH jump process. pH-resolved in situ small-angle X-ray scattering (SAXS) shows a continuous micelle-to-fibre transition, characterized by an enhanced core–shell contrast between pH 9 and pH 7 and micellar fusion into a flat membrane between pH 7 and pH 6, approximately. Below pH 6, homogeneous, infinitely long nanofibres form by peeling off the membranes. Eventually, the nanofibre network spontaneously forms a thixotropic hydrogel with fast recovery rates after applying an oscillatory strain amplitude out of the linear viscoelastic regime: after being submitted to strain amplitudes during 5 min, the hydrogel recovers about 80% and 100% of its initial elastic modulus after, respectively, 20 s and 10 min. Finally, the strength of the hydrogel depends on the medium's final pH, with an elastic modulus fivefold higher at pH 3 than at pH 6.

Journal Keywords: self-assembled fibrillar networks (SAFiN); small-angle X-ray scattering; thixotropic; biosurfactants; hydrogels; sophorolipids

Subject Areas: Chemistry, Biology and Bio-materials, Materials


Instruments: B21-High Throughput SAXS

Other Facilities: SWING at Soleil

Added On: 02/08/2021 13:36

Discipline Tags:

Biotechnology Biomaterials Physics Soft condensed matter physics Chemistry Materials Science Engineering & Technology Organic Chemistry Nanoscience/Nanotechnology Life Sciences & Biotech

Technical Tags:

Scattering Small Angle X-ray Scattering (SAXS)