Magnetically Hydrodynamic Behavior of Magnetoliposomes Designed for Liquid-Based Biomolecular Sensing

Magnetoliposomes (MLs), which combine liposomes (LPs) and magnetic nanoparticles (MNPs) as a composite, exhibit multifunctional properties as theragnostic and biosensor tools. In most biosensor applications, magnetic functions in MLs are used only for magnetic separation owing to the attraction force between MNPs and a permanent magnet. The present paper reports MLs as a magnetic sensing label based on magnetic analysis in liquid through alternating current susceptibility measurements. The MLs must contain a larger amount of MNPs in the membrane structure to obtain a larger magnetic signal. We systematically compare dynamic magnetic properties of MLs synthesized by two synthesis methods. The MLs synthesized by the double emulsion method contain more MNPs in the core of unilamellar LPs and generate a larger magnetic signal compared with that by the thin film hydration method. The magnetic relaxation behavior depends on the hydrodynamic behavior of both MLs and encapsulated MNPs.