Encapsulation and permeation properties of the polymerized ion pair amphiphile vesicle that has an additional carboxyl group on anionic chain

Abstract

Polymerizable ion pair amphiphiles (PIPA) that have two carboxyl groups on the anionic side of head group are prepared to increase binding between cationic and anionic chains and to compare them with previously reported PIPA with single carboxyl group. Additional binding from extra carboxyl group showed slow release of fluorescent marker and high long-term stability together with the advantages from polymerization. In addition one of the PIPAs introduced in this paper attained very high encapsulation of the marker and the polymerized PIPA vesicle was resistant to disruption by SDS or Triton X-100. This polymerization method was not dependent on addition of initiator and input of energy such as light or heat for polymerization, but initiated by only shaking at room temperature. Physical properties of PIPA vesicles were investigated in various points such as phase transition, release rate of marker, and ion permeation through bilayer membrane. Reasons for such high encapsulation and future applications are briefly discussed.