Abstract: A material with nanopillar structures extending from a substrate. The nanopillars are engageable by organisms to cause an interaction, such as cellular destruction.

Abstract: A material with nanopillar structures extending from a substrate. The nanopillars are engageable by organisms to cause an interaction, such as cellular destruction.

Abstract: A material with nanopillar structures extending from a substrate. The nanopillars are engageable by organisms to cause an interaction, such as cellular destruction.

Abstract: A magnetic colloidal system confined at the interface between two immiscible liquids and energized by an alternating magnetic field dynamically self-assembles into localized asters and arrays of asters. The colloidal system exhibits locomotion and shape change. By controlling a small external magnetic field applied parallel to the interface, structures can capture, transport, and position target particles.

Abstract: A magnetic colloidal system confined at the interface between two immiscible liquids and energized by an alternating magnetic field dynamically self-assembles into localized asters and arrays of asters. The colloidal system exhibits locomotion and shape change. By controlling a small external magnetic field applied parallel to the interface, structures can capture, transport, and position target particles.

Abstract: The present invention provides a method of driving liquid flow at or near a free surface using self-assembled structures composed of magnetic particles subjected to an external AC magnetic field. A plurality of magnetic particles are supported at or near a free surface of liquid by surface tension or buoyancy force. An AC magnetic field traverses the free surface and dipole-dipole interaction between particles produces in self-assembled snake structures which oscillate at the frequency of the traverse AC magnetic field. The snake structures independently move across the free surface and may merge with other snake structures or break up and coalesce into additional snake structures experiencing independent movement across the liquid surface. During this process, the snake structures produce asymmetric flow vortices across substantially the entirety of the free surface, effectuating liquid flow across the free surface.

Abstract: Self-assembly of magnetic microparticles in AC magnetic fields. Excitation of the system by an AC magnetic field provides a variety of patterns that can be controlled by adjusting the frequency and the amplitude of the field. At low particle densities the low-frequency magnetic excitation favors cluster phase formation, while high frequency excitation favors chains and netlike structures. For denser configurations, an abrupt transition to the network phase was obtained.

Abstract: A method and apparatus for concentration and separation of bacteria in confined geometries such as in thin fluid films and in channels. The bacteria live in an environment of a specified level of pH, so that an increase or decrease of pH levels stimulates the bacteria to avoid areas of unfavorable pH and swim in the direction of the pH gradient. To create the gradient of pH an electric current is transmitted through a thin film or channel containing bacteria. The transmission of the current results in electrolysis in the vicinity of the electrodes and deviation of the pH levels from the bulk values. The bacteria swim away from the electrodes toward the center of the cell, where the pH level is more favorable.

Abstract: Self-assembly of magnetic microparticles in AC magnetic fields. Excitation of the system by an AC magnetic field provides a variety of patterns that can be controlled by adjusting the frequency and the amplitude of the field. At low particle densities the low-frequency magnetic excitation favors cluster phase formation, while high frequency excitation favors chains and netlike structures. For denser configurations, an abrupt transition to the network phase was obtained.