Bruce Lee has focused on mussels at Michigan Technological University to develop a hydrogel actuator. Hydrogels that can change shape on command could be used to deliver pharmaceuticals, Lee explains. We’ve taken a hydrogel and made it into an actuator: something that can change shape or move, maybe by opening the door for a drug and letting it out. Lee's team used 3,4-dihydroxyphenylalanine a component of those mussel proteins and add it to a hydrogel pasted on to a piece of iron. pH changes stimulate bending of the hydrogel worm depending on where ions had been deposited electrolytically on the iron. A hydrogel could be programmed to adopt all manner of shapes by changing the placement of the ions, the composition of the hydrogel and the voltage. You can also remove the ions and reintroduce them in a different pattern, so that the same hydrogel can be reprogrammed to transform into a different shape.
Calculating chemistry on a different scale