A photonic DNA processor: concept and implementation

To deal with molecular information at a molecular level based on external signaling, a photonic DNA processor is a primal processing core of a nanoscale information system that works in molecular environment, for example, in situ. Use of photonic signals enables remote and spatio-temporal control of the processor. As an implementation example, we report a photonically-controlled DNA nanomachine which identifies and processes molecular information and implements physical processing as reporting the result using fluorescence signal. The nanomachine has two hairpin DNAs incorporating azobenzene and forms a tweezers-like structure. The hairpin structures are opened by ultraviolet-light irradiation, and a single-strand region is exposed to activate functionality in recognizing a target molecule. In contrast, visible-light irradiation makes the hairpin DNA close to inactivate the sensing function, and it releases the captured molecule. During activated term, the nanomachine changes its tweezers-like structure depending on existence or absence of the target molecule: the nanomachine transmutes into the closed state from the open state (initial state) by binding to the target molecule. Depending on the state, the nanomachine generates a fluorescence signal owing to fluorescence resonance energy transfer. In experiments, we demonstrated that the fluorescence intensities changed depending on existence and absence of the target molecule under photonic activation and inactivation. The result indicates that the nanomachine obtained information on the target molecule, changed the state, and reported the information to the outside world. In addition, we confirmed experimentally the functionality in measuring the concentration of the target molecule.image