For nanomedical applications such as delivering drugs or performing microsurgical procedures at specific places in the body, the ability to navigate bodily fluids with a high degree of control is crucial.
With this in mind, Ambarish Ghosh and Peer Fischer of the Rowland Institute at Harvard produced screw-like glass structures 1–2 micrometres long by nanofabrication. Depositing a thin layer of a ferromagnetic material on one side of each helix allowed the authors to direct the screws' motion with rotating magnetic fields. The duo even used the swimmers to spell out the initials of their institution (pictured).
The microswimmers can carry chemicals and push loads, and could be used as probes in rheological measurements difficult to perform by other techniques.