Force Scaling in Active Swarm of Microtubules via Magnetic Manipulation

Scalability refers to the ability of a system to enhance performance with increasing size. This ability is a defining feature of natural swarms such as ant and bee colonies. Extending this principle to artificial active matter has motivated the creation of molecular swarms composed of myosin-driven actin filaments and kinesin-driven microtubules (MTs). While these swarms exhibit cooperative transport behaviors that surpass the abilities of individual filaments, their collective force generation has remained unquantified. Here, we introduce a straightforward electromagnetic tweezer approach to directly measure the forces generated by MT swarms propelled by surface-bound kinesin motors. We find that force output changes with swarm size, demonstrating quantitative scalability and linking collective organization to mechanical performance. These results establish MT swarms as a model system for scalable, force-producing active matter and provide a foundation for designing biomolecular devices that exploit collective dynamics for microscale actuation and transport.