Multicompartment Vesicles Formation by Emulsification‐Induced Assembly of Poly(ethylene oxide)‐block‐poly(ε‐caprolactone) and Their Dual‐Loading Capability

Emulsification‐induced assembly is employed to allow structural diversity in nanoaggregates of a biocompatible amphiphilic polymer, poly(ethylene oxide)‐block‐poly(ε‐caprolactone). Onion‐like vesicles are efficiently produced by tuning the interfacial instability of the oil‐in‐water emulsion. The increase in the polymer concentration and use of the organic solvents with a low interfacial tension between water and the oil phase lead to a strong tendency of emulsion droplets to generate the onion‐like vesicles. The vesicular networks and fibers are also obtained by controlling the concentration and type of the surfactant, respectively. Interestingly, the onion‐like vesicles composed of alternating walls and water channels and the vesicular networks originated from a string of vesicles show dual‐loading ability for hydrophobic and hydrophilic dyes but slightly different loading capacities. This result indicates that the development of a methodology to fabricate well‐defined, unique nanostructures, such as multivesicular and multilamellar nanostructures, and subsequent elucidation of their structure–property relationships can provide useful guidance in the design of novel biomedical materials. Multicompartment vesicles, including onion‐like vesicles and vesicular networks, are constructed by tuning the interfacial instability of an oil‐in‐water emulsion of a single‐polymer molecular scaffold. The dual‐loading ability for hydrophobic and hydrophilic dyes is demonstrated with different loading capacities due to the spatial organization of each compartment constituting the onion‐like vesicles and vesicular networks.