Scientists have shown that surface acoustic waves (SAWs) can guide single‑stranded DNA molecules laid out on atomically flat hexagonal boron nitride (hBN) surfaces. The hBN sheet keeps the DNA confined while still allowing it to slide. A travelling acoustic wave, produced without any electric or magnetic contact, pushes the strands along the surface. The more power the SAW carries, the stronger the bias of the DNA motion in the wave direction, producing longer averages of displacement to the right. Despite this bias, individual molecules still wander in unpredictable, Brown‑motion‑like ways. The study used a custom SAW–hBN device that acts without relying on any special electrical or magnetic properties of the biomolecule, making it a versatile tool for nanofluidic manipulation.

The researchers recorded the motion of DNA molecules after turning the SAW on at different power levels (off, 1, 5, 15, 20, and 23 dBm). Histograms of net horizontal displacements revealed that higher SAW inputs produced broader distributions, with more trajectories ending to the right. Two‑dimensional probability maps for short trajectories (≤ 1 µm) showed a tight cluster at the origin, while maps for longer trajectories (> 1 µm) displayed a clear extension toward positive x, pointing to the SAW‑induced directional bias.

Although the acoustic field biases the motion, the stochastic Brownian motion remains dominant for most trajectory paths. This limits the precision of the directional transport but still opens pathways to on‑chip control of biomolecules in nanofluidic devices.

The work suggests new possibilities for manipulating single DNA molecules on chip, with potential relevance to advanced sequencing technologies and single‑molecule analysis.