Multi-compartment encapsulation of communicating droplets and droplet networks in hydrogel as a model for artificial cells

Abstract

Constructing a cell mimic is a major challenge posed by synthetic biologists. Efforts to this end have been primarily focused on lipid- and polymer-encapsulated containers, liposomes and polymersomes, respectively. Here, we introduce a multi-compartment, nested system comprising aqueous droplets stabilized in an oil/lipid mixture, all encapsulated in hydrogel. Functional capabilities (electrical and chemical communication) were imparted by protein nanopores spanning the lipid bilayer formed at the interface of the encapsulated aqueous droplets and the encasing hydrogel. Crucially, the compartmentalization enabled the formation of two adjoining lipid bilayers in a controlled manner, a requirement for the realization of a functional protocell or prototissue.

Microfluidics for Biosynthesizing: from Droplets and Vesicles to Artificial Cells

“…This is a simple and versatile method for artificial cells investigation. Sapra and co‐workers reported an artificial cell model through the encapsulating the multicompartments in hydrogel to form droplet networks . In this work, chemical communication can be achieved through the protein nanopores spanning the lipid bilayer.…”

“…In vivo, the communication between cells contributes to various biological processes. Scientists have dedicated to the construction of synthetic natural cells and synthetic cell–cell communication systems . de Greef and co‐workers reported the DNA‐based communication between neighboring artificial cells .…”

Cell-Free Synthetic Biology

“…The wheat germ platform has successfully expressed human, mouse, and mycobacterium desaturase complexes with the addition of liposomes, as well as plant solute transporters, using a similar strategy [110,111]. The E. coli platform has shown expression of a wide variety of membrane proteins including pores, channels, transporters, receptors, enzymes, and others while utilizing the exogenous addition of synthetic liposomes [106,112]…”

Synthetic tissues

“…Because the compartments are separated by individual, rather than double, bilayers, it is simpler to install communication between them with membrane proteins, including pores, channels, and transporters [12]. Oil drops containing clusters of droplets can be stabilized by encapsulation in hydrogels [14,15] ( Figure 3c,d). After transfer to aqueous media, 3D droplet networks are bounded by lipid bilayers facilitating communication with the environment [13,16] (Figure 3e).…”