Work

Magnetic Nanostructures Inside Cells: A Versatile Platform for Cellular Sensing, Manipulation, and Fabrication

Year: 2026

Type: article

Abstract: Magnetic manipulation of living cells traditionally relies on forces exerted by beads attached to the cell surface, where magnetic gradients are used to manoeuvre cell suspensions. Here, we demonstrate a strategy where cells with internalized magnetic nanostructures can be maneuvered as micro-agents under weak, spatially homogeneous rotating fields (< 8 mT). Using helical magnetic nanostructures, active microrheological measurements reporting local cytoplasmic mechanics are enabled, combined with programmable transport of the cells rolling on a surface. By tuning the magnetic drive while modulating cell-substrate adhesion, we resolve three distinct dynamical regimes: (1) nanomotor-only propulsion in fully adhered cells; (2) intermittent tumbling in semi-adhered cells where cytoskeletal remodelling creates pockets of reduced viscoelastic resistance; and (3) synchronous nanomotor-cell rolling that manoeuvres non-adherent cells from within. Quantitative torque balance reveals how intracellular thrust overcomes substrate friction, closing a key gap in our understanding of force transmission from the nanoscale to the cellular scale. These actuated cell-bots further act as tugboats, hydrodynamically steering neighbouring passive cells without physical contact, enabling label-free cell sorting and patterning, further supported by hydrodynamic simulations. Extending the concept, we demonstrate iron-calcium silicate core-shell nanomotors that guide pre-osteoblastic cells into predefined architectures while supporting mineralized matrix deposition, highlighting the platform's utility in regenerative medicine. Taken together, we describe a promising platform that integrates cellular interrogation, manipulation, and biofabrication within a single experimental system.

Source: Small

DOI: 10.1002/smll.202512144