How to build colonies of cargo-toting cells
U. PITTSBURGH (US)—Inspired by the social interactions of ants and slime molds, engineers have designed artificial cells capable of self-organizing into independent groups that can communicate and cooperate—and carry cargo.
Recently reported in the Proceedings of the National Academy of Sciences (PNAS), the research is a significant step toward producing synthetic cells that behave like natural organisms and could perform important, microscale functions in fields ranging from the chemical industry to medicine.
The “biologically inspired” devices function entirely through simple physical and chemical processes, behaving like complex natural organisms but without the complicated internal biochemistry, says corresponding author Anna Balazs, professor of chemical engineering at the University of Pittsburgh.
The microcapsules interact by secreting nanoparticles in a way similar to that used by biological cells signal to communicate and assemble into groups.
And with a nod to ants, the cells leave chemical trails as they travel, prompting fellow microcapsules to follow.
The researchers note that the communication hinges on the interaction between microcapsules exchanging two different types of nanoparticles. The “signaling” cell secretes nanoparticles known as agonists that prompt the second “target” microcapsule to emit nanoparticles known as antagonists.
Once the signaling cell goes dormant, the target cell likewise stops releasing antagonists—which makes the signaling cell start up again. The microcapsules get locked into a cycle that equates to an intercellular conversation, a dialogue humans could control by adjusting the capsules’ permeability and the quantity of nanoparticles they contain.
Locomotion results as the released nanoparticles alter the surface underneath the microcapsules. The cell’s polymer-based walls begin to push on the fluid surrounding the capsule and the fluid pushes back even harder, moving the capsule.
At the same time, the nanoparticles from the signaling cell pull it toward the target cells. Groups of capsules begin to form as the signaling cell rolls along, picking up target cells.
In practical use, Balazs says, the signaling cell could transport target cells loaded with cargo; the team’s next step is to control the order in which target cells are collected and dropped off.
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