A pH-stable dynamic DNA nanomachine with controllable conformational switching

The heterogeneity of physiological pH poses a major challenge to the stability and function of dynamic DNA nanomachines. Here, we systematically evaluate the performance of a six-helix DNA nanomachine (6H-NNM) as a model system. It maintains reversible, strand-displacement-driven conformational switching across pH 5-9 (>81% intact after 8 h) and remains functional under lysosome-mimicking acidic conditions. Our study provides an evaluation framework and performance benchmark for dynamic DNA devices in complex biological settings.