Many micromanipulation techniques rely on magnetic particles that are remotely actuated by an external magnetic field. Some devices called magnetic tweezers can "pull" on a DNA strand to study its elasticity. Yet these systems have the limitation that manipulation is only of single samples.

Researchers from INAC have produced the first "collection" of millions of sub-micrometric nanotweezers (also called nanojaws). Composed of two magnetic parts connected by a hinge, the jaws open in the presence of a magnetic field and close when this field disappears. The proper operation of these tweezers was demonstrated in an electron scanning microscope with a local field created in situ by a permanent magnetic microsphere.

Currently, the clamps are attached to their silicon substrate; in the future, they could be dispersed in a liquid. Designed to "pinch" samples of size comparable to theirs, they can interact collectively with biological samples or any other micro- or nanometer-sized elements.

The fabrication process was finalized at the Upstream Technological Platform (PTA). This work was supported by the French National Research Agency (project P2N NANO-SHARK).