Tetherless thermobiochemically actuated microgrippers:
T. G. Leong, C. L. Randall, B. R. Benson, N. Bassik, G. M. Stern and D. H. Gracias
We have demonstrated magnetic, mass-producible, tetherless microgrippers that can be remotely triggered by temperature and chemicals even under biologically relevant conditions. The microgrippers use a self contained actuation response, obviating the need for external tethers in operation. The grippers can be actuated en masse, even while spatially separated. We used the microgrippers to perform diverse functions, such as picking up a bead on a substrate and the removal of cells from tissue embedded at the end of a capillary.
Conventional microgrippers are usually tethered and actuated by mechanical, electrical, pneumatic, and hydraulic signals. Because the functional response of currently available
microgrippers is usually controlled through external wires or tubes, direct connections need to be made between the gripper and the control unit. These connections restrict device miniaturization and maneuverability. For example, a simple task such as the retrieval of an object from a tube is challenging at the millimeter and submillimeter scale, because tethered microgrippers must be threaded through the tube.
We have developed microgrippers that have the following characteristics. They are inexpensive and lithographically patterned. Since they are also magnetic and tetherless, they can be easily moved in narrow spaces, around corners and in coiled tubes (Fig. 1C) They can be actuated both with chemicals and temperature even under biologically benign conditions. The grippers were utilized to perform diverse functions such as picking up beads and excising cells from tissue. The ultimate goal is to create autonomous microgrippers that respond to biochemicals.
Fig. 1: Thermally and chemically triggered actuation, magnetic manipulation, and bead capture. (A and B) Optical images of 23 grippers (face-up and face-down) triggered to close en masse by heating. The grippers can also be triggered to close in response to chemicals (C) Overlaid movie sequence showing the remote-controlled manipulation of a mobile gripper in a coiled tube. (D) Schematic diagram depicting remote, magnetically directed movement and capture of a bead on a substrate. (E–I) Optical microscopy sequence showing the remote-controlled, thermally triggered capture of a dyed bead (275 mm) from among several clear beads.
T. G. Leong, C. L. Randall, B. R. Benson, N. Bassik, G. M. Stern and D. H. Gracias, “Tetherless Thermobiochemically Actuated Microgrippers”, Proceedings of the National Academy of Sciences USA (PNAS) 106, 703-708 (2009)
Style DIV, please skip.
Style DIV, please skip.