Microparticles, which are even smaller, can't be picked up by normal means, however much skill is used. This is exactly the task that research labs are working on - for example, when human cells, which are only a fraction of a millimeter in size, need to be picked up or positioned individually. An international team of researchers headed by PD Stefan Thalhammer (Helmholtz Zentrum, Munich) and Prof. Mandayam A. Srinivasan (MIT – Massachusetts Institute of Technology, Boston), in cooperation with attocube systems, has developed a solution to this challenge.

Gearbox - re-interpreted

To develop their solution, the researchers adapted the basic concepts of a gearbox. In the same way a gearbox transforms linear momentum, this invention can slow down the movement of a hand in nanometer-precise paths for mini-tweezers - the gripper. However, scaling-down the hand movement is not everything: A force sensor is mounted on the gripper, which detects if a particle has been picked up and positioned. The minimal force is extrapolated so that the operator can feel it. At the same time, the movement is displayed using an optical microscope.

The first is a joystick which picks up the movement of the human hand and transmits this to the second module, the controller. This ensures that the mini-tweezers are able to move in all three dimensions. These movements are performed by high-precision miniature motors from attocube systems. Force and path data are also combined in a control unit and analyzed. The gripper's movements are controlled by control electronics, which is also from attocube systems.

This allows the operator to guide the micromanipulator by sight. Support is also provided by haptic as well as optic images. The joystick is programmed in such a way that resistance is felt, as soon as the object is gripped. This gives an intuitive, realistic impression and the fact that these are not normal objects being moved, but the smallest particles only a few micrometers in size is often forgotten.