Synthetic Vesicles from Stimuli-responsive Amphiphiles

UoM administered thesis: Phd

  • Authors:
  • Wen Li

Abstract

The design of stimuli-responsive vesicles that become permeable, disassemble, or change shape in response to an external trigger or oscillating signal is a promising strategy in the development of drug delivery systems and soft materials, and may assist in the understanding of artificial cells and synthetic tissue. A cationic quaternary surfactant DDAB-CHO 19 has been synthesized that is structurally analogous to didodecyldimethylammonium bromide 1 (DDAB), but bears an aldehyde at the terminus of one lipid chain. Initially assemblies at thermodynamic equilibrium were created from this lipid. The addition of amines to suspensions of this aldehyde surfactant gave exchangeable “iminolipids” that self-assembled into vesicles in water. Any surfactant library obtained might make it possible to encourage interactions with specific materials and surfaces, providing a cationic hydrophilic coating surface. Then two approaches to forming assemblies under non-equilibrium conditions were explored. To create light-sensitive amphiphiles, a traceless method of removing hydrophilic solubilizing groups photochemically using diazene chemistry was explored. After uncaging this could give unfunctionalised hydrophobic alkyl groups that drive self-assembly in water. Furthermore the sulfite responsiveness of aldehydic amphiphiles was explored. Aldehydic amphiphiles were reacted with bisulfite-sulfite buffer to give a clock reaction. In combination with continuously stirred tank reactor (CSTR) this could generate an aldehyde-sulfite oscillating system which could produce pulses of self-assembled structures (e.g., vesicles).

Details

Original languageEnglish
Awarding Institution
Supervisors/Advisors
  • Robin Pritchard (Supervisor)
  • Simon Webb (Supervisor)
Award date31 Dec 2017