Stimuli-responsive vesicles as distributed artificial organelles for bacterial activation

Abstract

Intercellular communication is a hallmark of living systems. As such, engineering artificial cells that possess this behavior has been at the heart of activities in bottom-up synthetic biology. Communication between artificial and living cells has potential to confer novel capabilities to living organisms that could be exploited in biomedicine and biotechnology. However, most current approaches rely on the exchange of chemical signals that cannot be externally controlled. Here, we report two types of remote-controlled vesicle-based artificial organelles that translate physical inputs into chemical messages that lead to bacterial activation. Upon light or temperature stimulation, artificial cell membranes are activated, releasing signaling molecules that induce protein expression in Escherichia coli . This distributed approach differs from established methods for engineering stimuli-responsive bacteria. Here, artificial cells (as opposed to bacterial cells themselves) are the design unit. Having stimuli-responsive elements compartmentalized in artificial cells has potential applications in therapeutics, tissue engineering, and bioremediation. It will underpin the design of hybrid living/nonliving systems where temporal control over population interactions can be exerted.

A synthetic signalling network imitating the action of immune cells in response to bacterial metabolism

“…As such, our synthetic signalling cascade exemplifies how advanced life-like responses can be implemented with a relatively small number of molecular components, exploiting the modularity and programmability of nucleic-acid nanotechnology. Inspired by our solution, similar synthetic pathways could be implemented to program responses in the bacterial communities different from their death, for instance by loading the liposomes with inducers triggering protein synthesis [50], or exploiting the cell-trapping functionality to scaffold synthetic biofilms, valuable in biomaterial synthesis [65] and bioremediation [66, 67].…”

“…Successful attempts at establishing signalling networks between live and artificial cells have been reported, often involving one-way communication, e.g . triggering of bacterial gene expression [43–50], and more rarely twoway pathways leading to cell death [10]. However, these remarkable examples are still relatively simple, relying on one or a small number of individual functionalities, and thus failing to address the need to engineer more advanced emerging behaviours.…”

A Synthetic Signaling Network Imitating the Action of Immune Cells in Response to Bacterial Metabolism

“…The netosis-like behavior emerges from the coordinated activation of multiple biomimetic functions, including biosensing, morphological adaptation, and communication, exemplifying how advanced life-like responses can be implemented with a relatively small number of molecular components, exploiting the modularity and programmability of nucleic-acid nanotechnology. Inspired by our solution, similar synthetic pathways could be implemented to program responses in the bacterial communities different from their death, for instance by load-ing the liposomes with inducers triggering protein synthesis, [50] exploiting the cell-trapping functionality to engineer multispecies microbial consortia, [66] or scaffolding synthetic biofilms, valuable in biomaterial synthesis [67] and bioremediation. [68,69] The resulting "living biomaterials", [70] may also feature rheological properties which are dependent on the activity of the trapped cells, deserving future investigation.…”

“…Successful attempts at establishing signaling networks between live and artificial cells have been reported, often involving one-way communication, for example, triggering of bacterial gene expression, [43][44][45][46][47][48][49][50] and more rarely two-way pathways leading to cell death. [10] However, these remarkable examples are still relatively simple, relying on one or a small number of individual functionalities, and thus failing to address the need to engineer more advanced emerging behaviors.…”

Lipid vesicle-based molecular robots

“…29,30 For example, the controlled flux of cargo molecules in response to stimuli, 30,31 which can be used to mediate responses in living cells. 32…”