The promise of molecular programming lies in its ability to not only process information autonomously, but to do so in a biochemical context in order to sense and actuate matter. For its simplicity and its programmability, one attractive option for chemical information processing is built upon the DNA strand displacement (DSD) primitive, where a soup of rationally designed nucleotide sequences interact, react, and recombine over time in order to carry out sophisticated computation. The focus of this proposal is the creation of a reconfigurable DSD architecture akin to a molecular breadboard. Its purpose is to "scale-up" what is possible with this technology and to "scale-out" its adoption to new contexts and new areas of study. A small number of fast, robust and well-understood molecular components will be developed that compose seamlessly. The necessary tools to facilitate rapid circuit design and characterization will also be developed. The reconfigurable architecture will be designed to meet the challenges required in real-world applications ranging from point-of-care diagnostics to sensing and actuation within molecular systems. Due to its ease of use, we envision that this molecular breadboard will be an ideal vehicle to teach molecular programming and to facilitate wider adoption of DSD systems.
Building on a new leak reduction paradigm for DNA strand displacement systems, a new design for robust molecular computing gates will be developed, experimentally tested, and refined. By perfecting a set of molecular components suitable for use in modular and reconfigurable circuits, this will result in a fixed set of dozens of high quality gates that can be arbitrarily wired-up in order to create bespoke molecular circuits. A compiler will be developed that takes as input a circuit or logic function and provides as output the optimized set of biochemical "wires" necessary to activate the desired logic behavior. If successful, it will be possible to create and execute fast, leakless and robust molecular circuits, for circuits 2×-10× larger than have been previously demonstrated and with completion times 10×-100× faster. This increase in complexity creates an even greater need for design verification that will be addressed by the development of more efficient kinetic simulation software. The breadboard promises to be robust enough for immediate use in applications, such as diagnostics and molecular imaging, and in new contexts such as paper-based devices.
