Chapter 2 Molecular Robots Guided by Prescriptive

Traditional robots [Siegwart, 2004] rely for their function on computing to store internal representations of their goals and environment and to coordinate sensing and any actuating of components required in response. Moving robotics to the single-molecule level is possible in principle, but faces the limited ability of individual molecules to store complex information and programs. One strategy to overcome this problem is to use systems that can obtain complex behavior from the interaction of simple robots with their environment [Braitenberg, 1984, Brooks, 1991, Turing, 1936]. First steps in this direction were the development of DNA walkers [Bath and Turberfield, 2007], which have transitioned from being non-autonomous [Sherman and Seeman, 2004, Shin and Pierce, 2004], to being capable of directed but brief motion on one-dimensional tracks [Bath et al., 2005, Tian et al., 2005, Yin et al., 2008, Omabegho et al., 2009]. Here, we demonstrate that previously developed random walkers [Pei et al., 2006], so-called molecular spiders that comprise a streptavidin molecule as inert body and three deoxyribozymes as catalytic legs, exhibit elementary robotic behavior when interacting with a precisely defined environment. Single-molecule 0This work was coauthored by Kyle Lund, Anthony J. Manzo, Nadine Dabby, Nicole Michelotti, Alexander Johnson-Buck, Jeanette Nangreave, Steven Taylor, Renjun Pei, Milan N. Stojanovic*, Nils G. Walter*, Erik Winfree*, & Hao Yan* and published in 2010 [Lund et al., 2010] with the following contributions: AFM experiments were performed by K.L. (majority), J.N., and N. D.; analysis was performed by N. D., K.L., J.N., S.T., and supervised by E.W., and H.Y. Fluorescence microscopy and particle tracking analysis were performed by A.J.M., N.M., and A.J.B, supervised by N. G. W. Spiders were synthesized, purified, and their integrity confirmed and monitored by S.T. SPR experiments were performed by R. P. Research coordination by M.N.S., material transfer coordination by S.T., J.N., and K.L. Experimental design and manuscript was done with input from all authors.