Designing Artificial Cells towards a New Generation of Biosensors

Advances in synthetic biology have facilitated the development of cell-based and cell-free biosensors, enabling detection of molecular signals ranging from chemical contaminants to disease markers. Artificial cells have emerged as a platform to combine the sensing activities of cell-free sensors with certain membrane functions demonstrated in cell-based sensors, including molecular containment, protectivity, and small molecule gating. Recently, artificial cells have been designed to sense environmental molecules and initiate genetically-encoded responses. These sensors often utilize protein expression of membrane pores to release signaling molecules in response to a received input, facilitating communication with live and artificial cells. Progress in membrane engineering will allow the chassis to serve as an active participant in artificial cell sensing. The combination of biological and synthetic materials has great potential to generate new types of biosensors. Toward this goal, recent advances in artificial cell development have demonstrated the capacity to detect a variety of analytes and environmental changes by encapsulating genetically encoded sensors within bilayer membranes, expanding the contexts within which biologically based sensing can operate. This chassis not only acts as a container for cell-free sensors, but can also play an active role in artificial cell sensing by serving as an additional gate mediating the transfer of environmental information. Here, we focus on recent progress toward stimuli-responsive artificial cells and discuss strategies for membrane functionalization in order to expand cell-free biosensing capabilities and applications. The combination of biological and synthetic materials has great potential to generate new types of biosensors. Toward this goal, recent advances in artificial cell development have demonstrated the capacity to detect a variety of analytes and environmental changes by encapsulating genetically encoded sensors within bilayer membranes, expanding the contexts within which biologically based sensing can operate. This chassis not only acts as a container for cell-free sensors, but can also play an active role in artificial cell sensing by serving as an additional gate mediating the transfer of environmental information. Here, we focus on recent progress toward stimuli-responsive artificial cells and discuss strategies for membrane functionalization in order to expand cell-free biosensing capabilities and applications. membrane-permeable quorum-sensing molecules often used in artificial cell studies and bacterial communication pathways. The AHL N-3-(oxohexanoyl)-homoserine lactone (3OC6HSL) in particular has been explored in numerous artificial cell contexts. a substance, often a chemical or small molecule, that is detected, measured, or analyzed. an enclosed structure composed of compartmentalized bioactive molecules, which is capable of carrying out an essential activity of life – for example, sensing, signaling, communication, or growth/division. an analytical device which uses biological components to detect the presence of a specific target molecule. a strategy that aims to assemble biomimetic systems from isolated components – synthetic or natural – in order to carry out biological activities. a bottom-up approach that uses transcription and translation machinery extracted from the cellular environment in order to carry out engineered, genetically encoded behaviors in vitro in response to a specific analyte. the ability to express protein in the absence of living cells, resulting from the extraction of the cell’s transcription and translation machinery into an in vitro environment. a structural component that houses the molecular components required for gene expression. In the case of artificial cells, this is often a bilayer membrane. micron-scale vesicles which are often used for artificial cell studies due to their cell-like size. a genetically encoded assembly controlling the production of DNA, RNA, and proteins, which allows a system or cell to perform signal processing functions by turning a specific input into a desired output. the number of bilayers present in a vesicle membrane. A vesicle in which only one bilayer membrane is present is considered unilamellar. a vesicle composed of lipids. effects of sample or buffer components interfering with a signal, for example, by inhibiting transcription or translation in CFPS. an approach that aims to redirect the activities within living cells to generate new outputs and behaviors. a spherical structure composed of a bilayer membrane surrounding an aqueous interior. a top-down approach in which a living cell, often a bacterium or yeast, carries out engineered, genetically encoded behaviors in response to a specific signal using native expression machinery and cellular components.