Abstract
This report describes the construction of rudimentary DNA-based calculators that visually display outputs as fluorescent numerical characters within an array of wells in an assay plate. The displays are analogous to traditional electronic 7-segment displays. Deoxyribozyme-based logic gates are distributed according to specific requirements within pairs of wells, with each pair representing a different segment of the display. Activation of gates to cleave a fluorogenic substrate is controlled by subsequent addition of input oligonucleotides. The inputs represent a simple binary calculation event. The binary calculation is processed by the DNA calculator, and the correct fluorescent numerical answer is subsequently displayed. Using this system, a simplified 2-bit adder that visually displayed numerals with perfect digital behavior was built in a single day from existing laboratory reagents. Similarly, a 2-bit multiplier was also constructed. General binary and decimal-based 7-segment decoders are also under development. These general devices can be cascaded with a broad class of upstream calculation events such that any required downstream numerical output can be displayed.