Sodium Monododecylphosphate Vesicles Formed in Alcohol/Water Mixtures

Abstract

AbstractSodium monododecylphosphate (SDP), a typical single‐chain amphiphile (SCA), exhibits extremely low solubility in water, which limits the investigation on its aggregation behavior. In the current work, we introduced short‐ and medium‐chain alcohols into the SDP‐water system to improve its solubility. An isotropic phase was found to be formed in the presence of alcohol with a suitable dielectric constant (11–25) or alkyl chain (2–7 carbons). In addition, vesicular, dendritic, and micellar structures were identified in the isotropic phase, depending on the composition of the SDP/alcohol/H2O ternary systems. The structure, stability, permeability, and formation mechanism of the vesicles formed in the SDP/n‐pentanol (NPT)/H2O system were investigated. The vesicles have a unilamellar structure, with size‐selective permeability. They show remarkable stability upon long‐term storage, exposure to high temperature, and freeze‐thawing cycles, but are metastable in thermodynamics. The hydrogen bonding between SDP molecules plays an important role in the formation of vesicles. Furthermore, the SDP/NPT/H2O vesicles were used to construct three spatially segregated enzyme‐loaded compartments to support a cascade enzyme reaction. The chemical signal transduction among the enzyme‐loaded vesicles was achieved. This study provides a deeper understanding of the features of SDP vesicles and demonstrates their potential applications such as in biomembrane mimicking and micro‐reactors.