Control of electrochemical signals from quantum dots conjugated to organic materials by using DNA structure in an analog logic gate

• Two logic units were formulated from organic capped QDs and DNA.
• The units on Au generated diverse, pH dependent electrochemical outputs.
• Merged signals from the logic units were mapped via independently controlled pH.
• The input pH set for the logical units permitted different logic functions.

Various bio-logic gates have been studied intensively to overcome the rigidity of single-function silicon-based logic devices arising from combinations of various gates. Here, a simple control tool using electrochemical signals from quantum dots (QDs) was constructed using DNA and organic materials for multiple logic functions. The electrochemical redox current generated from QDs was controlled by the DNA structure. DNA structure, in turn, was dependent on the components (organic materials) and the input signal (pH). Independent electrochemical signals from two different logic units containing QDs were merged into a single analog-type logic gate, which was controlled by two inputs. We applied this electrochemical biodevice to a simple logic system and achieved various logic functions from the controlled pH input sets. This could be further improved by choosing QDs, ionic conditions, or DNA sequences. This research provides a feasible method for fabricating an artificial intelligence system.