Robotic sperm

Robotic sperm (also called spermbots) are biohybrid microrobots consisting of sperm cells and artificial microstructures. Currently there are two types of spermbots. The first type, the tubular spermbot, consists of a single sperm cell that is captured inside a microtube. Single bull sperm cells enter these microtubes and become trapped inside. The tail of the sperm is the driving force for the microtube. The second type, the helical spermbot, is a small helix structure which captures and transports single immotile sperm cells. In this case, a rotating magnetic field drives the helix in a screw-like motion. Both kinds of spermbots can be guided by weak magnetic fields. These two spermbot designs are hybrid microdevices, they consist of a living cell combined with synthetic attachments. Other approaches exist to create purely synthetic microdevices inspired by the swimming of natural sperm cells, i.e. with a biomimetic design, for example so-called Magnetosperm which are made of a flexible polymeric structure coated with a magnetic layer and can be actuated by a magnetic field.