Cargo Size Limits and Forces of Cell‐Driven Microtransport

The integration of motile cells into biohybrid microrobots offers unique properties such as sensitive responses to external stimuli, resilience, and intrinsic energy supply. Here, biohybrid cell–cargo systems that are driven by amoeboid Dictyostelium discoideum cells are studied and how the cargo speed and the resulting viscous drag force scales with increasing radius of the spherical cargo particle are explored. Using a simplified geometrical model of the cell–cargo interaction, the findings toward larger cargo sizes, which are not accessible with the experimental setup, are extrapolated and a maximal cargo size is predicted beyond which active cell‐driven movements will stall. The active forces exerted by the cells to move a cargo show mechanoresponsive adaptation and increase dramatically when challenged by an external pulling force, a mechanism that may become relevant when navigating cargo through complex heterogeneous environments. This study reveals the potentials and limitations of an amoeboid cell‐driven system that moves microparticles as large as red blood cells and up to ≈240 microns in diameter while exerting forces in the sub‐piconewton range on cargoes. The cell‐generated forces increase in response to persistent drag on the cargo, highlighting the mechanoresponsive adaptation of this biohybrid system in complex environments.