Biophysicists have found two ways to create molecular robots and spiders. The first, known as DNA walkers, have a body and feet made from DNA, with extra "anchor" strands of DNA that join the feet to a surface. When different "fuel" strands are put in front of a walker, they preferentially join to the anchor strands, thereby freeing the walker to move forward. The second type of robot, known as a molecular spider, has a protein body and DNA legs that chemically cleave tall strands of DNA on a surface.
Via Dr. Stefan Gruenwald