03 / Experiments

Experiments in view

Fluorescence recordings show how individual DNA molecules respond to constant, periodic, and stochastic electrical drives, alongside the nanofluidic structures used to confine them.

Dynamic confinement

Electrical drive protocols

The same nanocavity platform can impose fixed, periodic, or stochastic confinement. These recordings compare the molecular response under four representative drive protocols.

Constant voltageDNA confinement under a fixed applied-voltage amplitude.

NoiseMolecular response to a randomly varying drive signal.

Amplitude modulationPeriodic modulation drives repeatable conformational changes.

Stochastic landscapeDNA explores a stochastically driven potential landscape.

Voltage-dependent response

Increasing molecular tension

T4-DNA molecules span pairs of cavities. Increasing the applied voltage increases the electrokinetic tension and suppresses the fluctuations of the molecular contour between the wells.

Three molecules recorded at increasing voltage amplitude. The applied waveforms are shown beneath the fluorescence recordings.

Electron microscopy

Nanofabricated cavity arrays

Scanning electron micrographs show the patterned cavity arrays and a close view of a single cavity, where the insulating layer is opened to expose the ITO cavity electrode.

Scanning electron micrographs of nanofabricated circular cavity arrays and a close-up of a single cavity — Nanocavity arrays at multiple magnifications, from a single cavity to the extended patterned surface.

Conformation library

Confined λ-DNA shapes

Individual λ-DNA molecules adopt a broad range of compact and anisotropic conformations under cavity confinement. This montage shows representative single-molecule observations.

Montage of many fluorescence microscopy images showing different confined lambda-DNA conformations — Representative λ-DNA conformations measured in nanocavities.