C-12 vs C-3 substituted bile salts: An example of the effects of substituent position and orientation on the self-assembly of steroid surfactant isomers

Research output: Contribution to journalArticle

Abstract

Biomolecule derivatives are transversally used in nanotechnology. Deciphering their aggregation behavior is a crucial issue for the rational design of functional materials. To this end, it is necessary to build libraries of selectively functionalized analogues and infer general rules. In this work we enrich the highly applicative oriented collection of steroid derivatives, by reporting a rare example of C-12 selectively modified bile salt. While nature often exploits such position to encode functions, it is unusual and not trivial to prepare similar analogues in the laboratory. The introduction of a tert-butyl phenyl residue at C-12 provided a molecule with a self-assembly that remarkably switched from rigid pole-like structures to twisted ribbons at a biologically relevant critical temperature (∼25 °C). The system was characterized by microscopy and spectroscopy techniques and compared with the C-3 functionalized analogue. The twisted ribbons generate samples with a gel texture and a viscoelastic response. The parallel analysis of the two systems suggested that the observed thermoresponsive self-assemblies occur at similar critical temperatures and are probably dictated by the nature of the substituent, but involve aggregates with different structures depending on position and orientation of the substituent. This study highlights the self-assembly properties of two appealing thermoresponsive systems. Moreover, it adds fundamental insights hereto missing in the investigations of the relation between self-assembly and structure of synthetic steroids, which are valuable for the rational design of steroidal amphiphiles.

Details

Authors
  • Jacopo Cautela
  • Emilia Severoni
  • Carlos Redondo-Gómez
  • Maria Chiara di Gregorio
  • Alessandra Del Giudice
  • Simona Sennato
  • Roberta Angelini
  • Marco D'Abramo
  • Karin Schillén
  • Luciano Galantini
Organisations
External organisations
  • Sapienza University of Rome
  • University of Costa Rica
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Materials Chemistry
  • Biochemistry and Molecular Biology

Keywords

  • Bile acid, Hydrogel, Steroid derivatives, Thermoresponsive self-assembly
Original languageEnglish
Article number110556
JournalColloids and Surfaces B: Biointerfaces
Volume185
Publication statusPublished - 2020
Publication categoryResearch
Peer-reviewedYes