Manipulation of encapsulated artificial phospholipid membranes using sub-micellar lysolipid concentrations

Abstract

Engineered artificial cells often involve phospholipid membranes in the form of vesicles or membrane mimics. Droplet interface bilayers (DIBs) constitute a commonly used membrane mimic within synthetic biology. 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 by ready-to-use 3D-printed microfluidic devices. The eDIB capsules were exposed to various concentrations of membrane tension-altering lysophosphatidylcholine (LPC), in order to investigate the interaction of lysolipids with three-dimensional, 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, as well as the functionalities of artificial cells, toward responsive soft material developments and drug delivery applications.