Photocleavage control of nucleated DNA nanosystems--the influence of surface strand sterics.

We use sterically inaccessible 'seed' strands, released from a surface into solution by photocleavage to initiate a nucleated DNA polymerization reaction. We demonstrate control of the quantity of 'seed' release and that hairpin steric protection of the 'seed' leads to less 'leaky' surfaces. This polymerization is a model system for surface-photocleavage initiation of sub-stoichiometric reaction cascades; these cascades should find use as a component of labs-on-chips capable of bioanalytical and DNA-computing tasks.

Positional photocleavage control of DNA-based nanoswitches.

DNA-based switches are currently operated by manual solution-phase addition of 'set-strands'. We demonstrate another operation method-sterically inaccessible 'set-strands', released from a surface into solution by spatially controlled photocleavage. This technique will enable microarrays of set-strands to operate many DNA-based switches in self-contained computational and diagnostic devices.