Reset-free DNA logic circuits for real-time input processing and memory

DNA logic circuits have great potential for biocompatible and programmable computations; however, current designs require reset processes, which restrict real-time data processing and memory functionality. This study proposes a reset-free approach on the basis of toehold-mediated chain reaction (TCR), which enables continuous and reversible strand migration within dual-rail units. By localizing TCR components on two-dimensional DNA origami templates, various combinational logic gates (e.g., AND and OR gates) and memory elements were implemented, including set-reset and data latches, as well as advanced cascaded registers. These circuits consistently processed new inputs and retained outputs over multiple sequential operations. The proposed reset-free TCR framework offers a mechanism most analogous to electronic circuit operation and demonstrates considerable potential for practical applications in biosensing, diagnostics, and synthetic biology.