Acoustically triggered nano/micro-scale propulsion devices

An ultrasound system for propelling an acoustically responsive structure, comprising:

• a mechanism that supplies one or more tubular structures in a fluid medium, the one or more tubular structures each having one or more layers including an inner layer having an electrostatic surface and an ultrasound-responsive substance coupled to the inner layer by electrostatic interaction and configured to form gaseous bubbles in the fluid medium in response to an ultrasound pulse, wherein the bubbles exit the tubular structure to propel the tubular structure to move in the fluid medium;
• and
• a mechanism that produces ultrasonic acoustic energy and focuses the ultrasonic acoustic energy at a particular region where the one or more tubular structures are located to cause vaporization in the fluid medium at an interface with the ultrasound-responsive substance that triggers the bubbles to form.

A device to locomote in a fluid by acoustic energy, comprising:

• two or more segments structured to form a rod having an interior cavity spanning from an opening at one end of the rod,
• wherein at least one of the segments includes an outer surface of a modifiable material capable of being functionalized,
• wherein the rod is structured to interact with an external ultrasound pulse to create a pressure gradient within the interior cavity to propel the device in the fluid.

A device to locomote in a fluid by acoustic energy, comprising:

• a rod including two or more segments structured to include an interior cavity spanning from an opening at one end of the rod, the interior cavity including a surface configured to be rough or hydrophobic,
• wherein at least one of the two or more segments includes an outer surface of a modifiable material capable of being functionalized,
• wherein the rod is structured to interact with ultrasound pulses to create a vaporization of the fluid to form gaseous bubbles along the surface of the interior cavity to propel the device in the fluid.