Liposome array on a power-free microfluidic device for analysis of nanopore formation

Abstract

Liposome-based sensing technology that forms nanopores on membranes has attracted significant attention. We analyzed the characteristics of nanopore formation on liposomal membranes that result from interactions between amphotericin B (AmB) and ergosterol. Based on this property, we propose a new system that examines nanopore formation on liposomal membranes. We demonstrated the usefulness of this system by evaluating the effect of shodoamide C (ShC), which acts as a potentiator. Liposomes were prepared with a water-in-oil-in-water emulsion method and introduced into a microfluidic device through a power-free pumping method without the need for an external power supply. AmB binds to ergosterol in the lipid bilayer and creates nanopores that allow encapsulated molecules to escape. We controlled the release time by adjusting the mole fraction of ergosterol and the concentration of AmB. Fluorescence observation revealed that the release time depends on membrane composition and the concentration of AmB. We examined the effect of ShC, which enhances the activity of AmB, and found that this compound increases membrane permeability and accelerates molecular release. This study demonstrates the first analytical system that measures the activity of AmB and its enhancers or inhibitors through release profiles that depend on concentration. The system provides a practical tool for screening compounds that act on membranes. Our analytical system opens new opportunities for the development of membrane-active therapeutics and for progress in drug discovery and synthetic biology.