Manipulation of encapsulated artificial phospholipid membranes using sub-micellar lysolipid concentrations.
Droplet Interface Bilayers (DIBs) constitute a commonly used model of artificial membranes for molecular biology studies with applications in synthetic biology research. However, these model membranes have limited accessibility due to their requirement to be surrounded by an oil environment. Here, we demonstrate in-situ bilayer manipulation of submillimeter, free-standing, encapsulated droplet interface bilayers (eDIBs) in hydrogel capsules formed using dual-material, 3D-printed microfluidic devices. These microfluidic devices required no post-fabrication assembly, nor surface treatment to achieve the high-order emulsification, required for the formation of robust eDIBs. The eDIB capsules were exposed to various concentrations of lysophosphatidylcholine (LPC), in order to investigate the interaction of lysolipids with three-dimensional, encapsulated droplet bilayer networks. Micellar LPC concentrations trigger the bursting of the eDIB droplets, while at concentrations below the critical micelle concentration (CMC), the encapsulated aqueous inner droplet networks endure structural changes, precisely affecting the DIB contact angles and bilayer area. Manipulation of these enclosed, 3D-orchestrated membrane mimics facilitates the exploration of readily accessible compartmentalized artificial cellular machinery. Collectively, the multi-compartmentalized capsules and the lysolipid-mediated membrane modulation, introduce a chemical approach to control the properties and mechanics of artificial cellular membranes, toward responsive soft material developments.