Gripping stuff

. The devices have been devised by a team led by Professor David Gracias at John Hopkins University in Maryland in the USA. They are made of gold plated nickel with six digits extending out of a single palm. The joints contain thin layers of chromium and copper with stress characteristics that would normally make the digits curl closed. However, a polymer resin has been added that prevents them from closing. When the microgripper arrives at its destination, it is warmed to 40 deg C, equivalent to a moderate fever in humans, which is sufficient to soften the resin, allowing the gripper to close on whatever it has been placed against. Alternatively, some non toxic biological solutions can also weaken the polymer, and allow the digits to close. In laboratory experiments, the researchers used a magnet guided microgripper to grab and transport a dyed bead from among a group of colourless beads in an aqueous solution. Team members were also able to capture numbers of live animal cells from a cell mass at the end of a capillary tube. The cells were still alive 72 hours later.