Reversible logic circuits made of DNA.

We report reversible logic circuits made of DNA. The circuits are based on an AND gate that is designed to be thermodynamically and kinetically reversible and to respond nonlinearly to the concentrations of its input molecules. The circuits continuously recompute their outputs, allowing them to respond to changing inputs. They are robust to imperfections in their inputs

Template-directed conjugation of heterogeneous oligonucleotides to a homobifunctional molecule for programmable supramolecular assembly

Nanoscience aspires to mimic nature's control over functional molecular assemblies. Here we present a templating technique for the efficient attachment of two different oligonucleotides to a homobifunctional molecule, enabling its controlled and programmable placement within a DNA nanostructure. We demonstrate its application to a range of organic molecules with different conjugation chemistries and water solubilities. We show that the two oligonucleotide adapters can be used to integrate a bifunctional cyanine dye into a self-assembled 3D-DNA origami nanostructure, giving control of both position and orientation. We also demonstrate the use of both adapters to exert dynamic control over the environment of the target molecule by means of a series of strand-displacement reactions

DNA nanomachines.

We are learning to build synthetic molecular machinery from DNA. This research is inspired by biological systems in which individual molecules act, singly and in concert, as specialized machines: our ambition is to create new technologies to perform tasks that are currently beyond our reach. DNA nanomachines are made by self-assembly, using techniques that rely on the sequence-specific interactions that bind complementary oligonucleotides together in a double helix. They can be activated by interactions with specific signalling molecules or by changes in their environment. Devices that change state in response to an external trigger might be used for molecular sensing, intelligent drug delivery or programmable chemical synthesis. Biological molecular motors that carry cargoes within cells have inspired the construction of rudimentary DNA walkers that run along self-assembled tracks. It has even proved possible to create DNA motors that move autonomously, obtaining energy by catalysing the reaction of DNA or RNA fuels

Combinatorial displacement of DNA strands: application to matrix multiplication and weighted sums.

DNA multiplication tables: A combinatorial mechanism for DNA strand displacement shares the same structure as matrix multiplication (see scheme). This system can be used to perform linear operations on DNA concentrations, such as the calculation of a weighted sum. Copyright © 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim

Molecular machinery built from DNA

DNA can be used as both construction material and fuel for molecular motors. Systems of motors and tracks can be constructed and movement of the motor along the track can be directly observed. The path that a taken by a motor as it navigates a network of tracks can be programmed by instructions that are added externally or carried by the motor itself. Such systems might be used as part molecular assembly lines that can be dynamically reconfigured in response to changing demands. © 2013 American Institute of Physics