In another winning turn for our upcoming robotic overlords, engineers at the University of Twente in The Netherlands have reported in Applied Physics Letters the development of “MagnetoSperm” that can be controlled with relatively weak external magnets. Though it’s about six times larger than average human sperm, it looks and behaves similar to the real deal.
The shape is designed from a polymer called SU-8 which provided the necessary strength while being easy to work with. The propulsion is made possible by a thin layer of cobalt-nickel on the head of the MagnetoSperm that is acted on by nearby magnets. While the technology is being developed for the Borg to assimilate us, it may in the meantime improve in vitro fertilization and lead to new drug delivery techniques.
From the study abstract:
This system consists of a structure resembling a sperm-cell with a magnetic head and a flexible tail of 42 μm and 280 μm in length, respectively. The thickness, length, and width of this structure are 5.2 μm, 322 μm, and 42 μm, respectively. The magnetic head includes a 200 nm-thick cobalt-nickel layer. The cobalt-nickel layer provides a dipole moment and allows the flexible structure to align along oscillating weak (less than 5 mT) magnetic field lines, and hence generates a propulsion thrust force that overcomes the drag force. The frequency response of this system shows that the propulsion mechanism allows for swimming at an average speed of 158 ± 32 μm/s at alternating weak magnetic field of 45 Hz. In addition, we experimentally demonstrate controlled steering of the flexible structure towards reference positions.
Study in Applied Physics Letters: MagnetoSperm: A microrobot that navigates using weak magnetic fields…