Two vesicles, made in precisely the same way and placed in the same fluid, can nonetheless come to treat one another differently, one passing by while the other is drawn in, pushed away, or pursued. A new theoretical model from the Max Planck Institute for Dynamics and Self-Organization, reported in the journal Newton, suggests that this quiet divergence arises from within: enzymatic reactions bend the chemistry of each tiny membrane sac in its own direction, and that private imbalance becomes a public relationship with its neighbor. It is a reminder that in the small, sealed worlds of matter,
Identical Vesicles Behave Differently: Spontaneous Symmetry Breaking Yields Lifelike Interactions
Identical vesicles can still end up behaving like different personalities
Mark
So what's the basic surprise here?
Mimi
That identical vesicles don't have to act identically. Chemistry inside each one evolves, and that breaks the symmetry between them.
Mark
And that produces the one-sided interactions?
Mimi
Yes. If one vesicle has more of a chemical inside than outside and the other has less, their effects on each other aren't mirror images.
Mark
Does that really break Newton's third law?
Luke
The source says it "seemingly" violates it, and that wording matters. Nonreciprocal systems typically involve energy or chemistry being supplied from elsewhere, though the article doesn't unpack that.
Mark
What can the vesicles actually do?
Mimi
They can ignore, attract, repel or chase each other, and switch between those over time.
Mark
Can people steer that?
Mimi
Per the researchers, yes: adding more reactants, for example, can change the interactions.
Luke
Worth stressing this is a model. The article describes no experiment showing vesicles chasing each other, so the behavior is predicted, not observed.
Mark
And the origin-of-life angle?
Luke
It's framed as a perspective. Protocells with similar properties are "thought" to have existed, so that's a suggestion about how signaling, sensing and movement might emerge, not a demonstration.
Der Puls
- Two identical membrane vesicles, prepared the same way, can begin acting like rivals, strangers, or pursuers in the same fluid.
- Enzymatic reactions inside each sac push its chemistry out of balance, turning a shared start into an uneven and shifting relationship.
- When one vesicle holds more of a chemical than its surroundings while its neighbor holds less, the pair's interaction tilts into asymmetry.
- Researchers can tune these interactions from outside by adding reactants, steering the population toward new behaviors, though the findings remain a model awaiting testing against real vesicles.
Two vesicles, made in precisely the same way and placed in the same fluid, can nonetheless come to treat one another differently, one passing by while the other is drawn in, pushed away, or pursued. A new theoretical model from the Max Planck Institute for Dynamics and Self-Organization, reported in the journal Newton, suggests that this quiet divergence arises from within: enzymatic reactions bend the chemistry of each tiny membrane sac in its own direction, and that private imbalance becomes a public relationship with its neighbor. It is a reminder that in the small, sealed worlds of matter, even identical beginnings can grow into distinct characters, and that the first hints of responsiveness, perhaps even of life, may have arisen this way.
Imagine two vesicles, tiny membrane-bound sacs, prepared in exactly the same way and placed in the same fluid. Yet they can end up behaving as though they had different personalities: one ignores the other, another drifts toward it, one pushes away, another gives chase. A new theoretical model from physicists at the Max Planck Institute for Dynamics and Self-Organization describes how this happens, and the work appears in the journal Newton.
The researchers, from the institute's Department of Living Matter Physics, study nonreciprocal active matter, where agents act on one another unequally, seemingly bending Newton's third law. Such asymmetry can give rise to self-propulsion, molecular regulation, and collective motion. The team proposes that these unequal interactions can arise spontaneously between chemically active vesicles, which can shift among ignoring, attracting, repelling, and chasing.
The mechanism begins with enzymatic activity inside semipermeable vesicles. That activity creates a concentration gradient between each interior and its surroundings, and the gradient shapes behavior. Asymmetry appears when one vesicle holds more of the chemical than its surroundings while its neighbor holds less.
The situation is never fixed. As reactions continue, it evolves on its own or can be guided from outside, for instance by adding reactants. A population may start out identical yet remain highly dynamic, its interactions depending on each vesicle's changing chemical state.
Jakob Metson, the study's first author, called this a fundamentally new class of intelligent active matter, emerging through a breaking of symmetry in the chemistry. Ramin Golestanian, a director at the institute, highlighted the framework's flexibility and its grounding in emergent symmetries and their spontaneous breaking.
The authors also look back toward life's origins, when protocells with similar properties may have existed. The framework offers a way to think about how signaling, sensing, and movement could have emerged. Still, this is a model rather than an observation of protocells, and the next step is testing its predictions against real chemically active vesicles.
Imagine two vesicles, tiny membrane-bound sacs, prepared in exactly the same way. Put them in the same fluid and they can still end up behaving as if they had different personalities: one ignores the other, or drifts toward it, or pushes away, or follows it. A new theoretical model from physicists at the Max Planck Institute for Dynamics and Self-Organization (MPI-DS) describes how that can happen, and the work is published in the journal Newton.
The researchers come from the institute's Department of Living Matter Physics. Their subject is nonreciprocal active matter, a field in which agents act on one another unequally, in a way that seems to violate Newton's third law. This kind of asymmetry can give rise to traits such as self-propulsion, molecular regulation and collective motion.
What the team proposes is that such nonreciprocal interactions can arise spontaneously between chemically active vesicles. In the model, the vesicles can dynamically switch among four modes: ignoring, attracting, repelling and chasing each other.
The mechanism rests on enzymatic activity inside semipermeable vesicles. That activity can set up a chemical concentration gradient between a vesicle's interior and its surroundings, and the gradient shapes how the vesicle behaves. Nonreciprocity appears between two vesicles when the chemical concentration inside one is higher than in its surroundings, while the concentration inside the other is lower than in its own surroundings.
The state is not fixed. As the enzymatic reactions continue, the situation can change over time, either on its own or in a controlled way. Researchers can alter the interactions from outside by manipulating the chemistry, for instance by adding more reactants. So a population of vesicles can be made identical at the start, yet their interactions remain highly dynamic and depend on each one's evolving chemical state.
"In our work, we describe a fundamentally new class of intelligent active matter systems," said Jakob Metson, the study's first author. He added that the nonreciprocal interactions emerge spontaneously through a breaking of the symmetry of the chemical reactions.
Ramin Golestanian, a director at MPI-DS, said the framework offers a remarkable degree of flexibility for the emergent properties of an active suspension. The concept underlying the work, he said, is that of emergent symmetries and the spontaneous symmetry breaking associated with them.
The authors also point toward the origins of life. Protocells with similar properties are thought to have emerged then, and the framework offers a perspective on how defining features of life, such as signaling, sensing and movement, could arise. The work is a model rather than an observation of protocells, so the next question is how well its predictions hold up against real chemically active vesicles.
Bemerkenswerte Zitate
We describe a fundamentally new class of intelligent active matter systems.— Jakob Metson, first author
The framework gives a remarkable degree of flexibility for the emergent properties of the active suspension, built on emergent symmetries and spontaneous symmetry breaking.— Ramin Golestanian, director at MPI-DS (paraphrased)
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