Refined Design of DNA Logic Gate for Implementing DNA-based Three-level Circuit

DNA computing circuits are favored by researchers due to their high density, high parallelism, and biocompatibility. However, compared with electronic circuits, current DNA circuits have significant errors in understanding the OFF state and logic “0”. Nowadays, DNA circuits only have two input states: logic “0” and logic “1”, where logic “0” also means the OFF state. Corresponding to an electronic circuit, it is more like an on-off switch than a logic circuit. To correct this conceptual confusion, we propose a three-level circuit. The circuit divides the input signal into three cases: “none”, logic “0” and logic “1”. In subsequent experiments, 34 input combinations of primary AND gate, OR gate and secondary AND-OR, OR-AND cascade circuits were successfully implemented to perform the operation, which distinguished the OFF state and logic “0” correctly. Based on this, we implemented a more complex voting operation with only 12 strands successfully. We believe that our redefinition of OFF state and logic “0” will promote tremendous developments in DNA computing circuits.