Abstract
Recent years have seen the emergence of synthetic biology, which encompasses
the engineering of living organisms as well as the implementation of biological
behavior in non-living substrates. Many of these engineered systems have
harnessed the diverse toolkit of proteins, genes, and cellular processes that
nature offers. While these efforts have been fruitful, they have also illustrated the
difficulty associated with programming highly complex functions by tapping into
cellular processes. Another set of efforts has focused on building circuits,
performing computation, and constructing nanoscale machines using nucleic
acids. Zhang et al., 2007, Science 318, 1121�1125 and Yin et al., 2008, Nature 451,
318�322 recently demonstrated flexible approaches for the modular construction
of such biochemical devices exclusively using DNA. These approaches have
exciting implications both for engineering living cells and for mimicking life-like
behavior at the nanoscale.