Original title: Active embracement enables autonomous tweezing in active star polymers
Marco Musacchio, Davide Breoni, Iman Abdoli, Luca Tubiana +2 · August 2026
Living things can reshape themselves on their own, but artificial materials struggle to do this. Researchers studied active star polymers, which are star-shaped structures made of a central core with self-propelledMoving on their own, like a robot with a motor., moving arms. Using vibrating robots linked together alongside computer simulations, the team discovered a behavior called active embracement. Instead of staying pushed apart like passive materials do, the moving arms drive the star polymer to switch from an open shape into a tightly collapsed, hugging state. The researchers found that single star polymers can fold into compact balls, multiple star polymers can wrap around and embrace each other, and they can spontaneously grab nearby passive particles. This allows these active star polymers to act like tiny autonomous tweezers.
Imagine a group of people at a party, each with their arms outstretched, naturally keeping some distance to avoid bumping into each other. Now suppose each person starts moving around on their own, and as they move, they start pulling their arms in and hugging themselves. Eventually, they might hug each other and even grab onto nearby objects. In this paper, the star polymers are like those people, and the active motion makes them collapse and embrace, turning them into tiny tweezers.
This discovery could lead to smart materials that automatically capture and release microscopic cargo, like targeted drug delivery or self-healing coatings. Engineers might design polymers that reconfigure on demand, mimicking biological systems.
The abstract doesn't say what the limitations are, but it notes that the work bridges macroscopic robotic collectives and microscopic polymer physics, suggesting it is a proof-of-concept. Practical applications for smart materials remain to be realized.
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Active embracement enables autonomous tweezing in active star polymers — Marco Musacchio, Davide Breoni, Iman Abdoli et al.
Abstract licence: CC0
Explanation generated by Synthesis from the abstract — it is not the original paper. This is a preprint, so it hasn't necessarily been peer reviewed.