DNA Sequential Logic Circuits for Reversible Counters and Dynamic Biomolecular Sensing

The capacity to retain and precisely release historical data at the right moments is typically managed by sequential logic circuits within computer systems. However, the reusability and autonomy of DNA sequential logic circuits still need to be developed. To bridge this gap, a series of sequential logic circuits are implemented by constructing a DNA strand replacement system regulated by a nicking enzyme (nickase). This nickase-integrated system dynamically resolves the thermodynamic-kinetic conflict, offering spatiotemporal control over strand displacement. These circuits include Set-Reset latches (SR-latches) constructed with NOR and NAND gates, along with Data latches (D-latches), are designed with simplicity, autonomy, and reusability. Furthermore, addition, subtraction, and reversible counters leveraging these foundational circuits are successfully constructed. These latches are further applied to transient miRNA recording, environmental toxin detection, and real-time ATP imaging in living cells.