Direct Synthesis of Prussian Blue Nanoparticles in Liposomes Incorporating Natural Ion Channels for Cs+ Adsorption and Particle Size Control

Coordination polymer (CP) nanoparticles (NPs) formed by a self-assembly of organic ligands and metal ions are one of the attractive materials for molecular capture and deliver/release in aqueous media. Control of particle size and prevention of aggregation among CP NPs are important factors for improving their adsorption capability in water. We demonstrate here the potential of a liposome incorporating an antibiotic ion channel as a vessel for synthesizing Prussian blue (PB) NPs, being a typical CP. In the formation of PB NPs within liposomes, the influx rate of Fe2+ ions into liposome encapsulated [Fe(CN)6]3– through channels was fundamental for the change of NPs’ sizes. The optimized PB NP–liposome composite showed higher adsorption capacity of Cs+ ions than that of aggregated PB NPs that are prepared without liposome in aqueous media.