Little machines, so small they can enter your body and zoom around fixing stuff.  The great scifi classic ‘Fantastic Voyage’ was all about that, shrinking not just a space ship but all of the folks inside and then zooming around the blood stream.  While that will never happen, building tools so small that they can work inside the body without cutting big holes in you is an important area.  Scientists are building all sorts of devices that will hold and cut and mend small parts in your body.  The big challenge is building them and then powering them.  One way to provide power is to use polymers that respond to heating or some external chemicals.  The polymer changes its shape and causes the parts that the polymer is attached to—in this case the arms of a gripper—to close.  These tiny grippers might be used to grab cancer cells and then bring back samples for analysis.  For more information: http://tinyurl.com/tinycutters