Abstract: The flow of particles (18) in an aperture (10) between two reservoirs (14) and (15) is controlled by suspending the particles (18) in a fluid (17) within the aperture (10), applying a potential difference across the aperture (10) so as to tend to electrophoretically transport the particles (18) between a region of higher potential field and a region of lower potential in the fluid (17), applying a pressure differential across the aperture (10) so as to tend to transfer the fluid (17) with the particles (18) therein though the aperture (10) from a high-pressure reservoir (14) to a low-pressure reservoir (15), and adjusting the potential difference and/or the pressure differential across the aperture (10) in order to achieve precise control over the translation of the particles (18) within the aperture (10).

Abstract: A method is provided for detecting, measuring or controlling particles and/or electromagnetic radiation, comprising providing a deformable material containing a deformable aperture defining a path for particles or radiation, adjusting the deformable aperture to a prescribed geometry and/or size by deforming the deformable material to change at least one of the parameters of the path defined by the deformable aperture, and causing the particle or radiation to be detected, measured or controlled to enter the deformable aperture. The method includes the step of monitoring the geometry and/or size of the deformable aperture and controlling the adjustment of the size of the deformable aperture in response to such monitoring. The required apparatus is easily fabricated from inexpensive materials.