Abstract: Apparatus and methods are provided for interacting light with particles, including but not limited to biological matter such as cells, in unique and highly useful ways. Optophoresis consists of subjecting particles to various optical forces, especially optical gradient forces, and more particularly moving optical gradient forces, so as to obtain useful results. In biology, this technology represents a practical approach to probing the inner workings of a living cell, preferably without any dyes, labels or other markers. The invention includes methods for separating particles in a medium where the particles having differing dielectric constants by providing a medium having a dielectric constant between the dielectric constants of the particles, subjecting the particles in the media to an optical gradient field, and separating the particles.

Abstract: Apparatus and methods are provided for interacting light with particles, including but not limited to biological matter such as cells, in unique and highly useful ways. Optophoresis consists of subjecting particles to various optical forces, especially optical gradient forces, and more particularly moving optical gradient forces, so as to obtain useful results. In biology, this technology represents a practical approach to probing the inner workings of a living cell, preferably without any dyes, labels or other markers. In one aspect, a method is provided for separating particles having different dielectric constants by separating the particles in a medium having a dielectric constant chosen to enhance the sensitivity of the discrimination between the particles, and changing the medium to one having a dielectric constant which causes faster separation between the particles.

Abstract: Apparatus and methods are provided for interacting light with particles, including but not limited to biological matter such as cells, in unique and highly useful ways. Optophoresis consists of subjecting particles to various optical forces, especially optical gradient forces, and more particularly moving optical gradient forces, so as to obtain useful results. In biology, this technology represents a practical approach to probing the inner workings of a living cell, preferably without any dyes, labels or other markers. In one aspect, a method is provided for analyzing particles by electrokinetically moving the particles and subjecting the particles to optical forces for analysis.

Abstract: Apparatus and methods are provided for interacting light with particles, including but not limited to biological matter such as cells, in unique and highly useful ways. Optophoresis consists of subjecting particles to various optical forces, especially optical gradient forces, and more particularly moving optical gradient forces, so as to obtain useful results. In biology, this technology represents a practical approach to probing the inner workings of a living cell, preferably without any dyes, labels or other markers. In one aspect, a method is provided for separating a population of particles according to size by subjecting the particles to an optical gradient pattern having a defined spatial periodicity and moving the gradient relative to the particles, wherein the improvement comprises selecting the spatial periodicity of the gradient to have a differential effect on differently sized particles.

Abstract: Apparatus and methods are provided for interacting light with particles, including but not limited to biological matter such as cells, in unique and highly useful ways. Optophoresis consists of subjecting particles to various optical forces, especially optical gradient forces, and more particularly moving optical gradient forces, so as to obtain useful results. In biology, this technology represents a practical approach to probing the inner workings of a living cell, preferably without any dyes, labels or other markers. In one aspect, a method is provided for interacting an optical gradient field in three dimensions with a particle by interfering two beams to generate a plurality of planar fronts, providing a plurality of particles in a medium, and moving the planar fronts relative to the particles, whereby the particles are separated at least in part based upon the dielectric constant of the particles.

Abstract: Apparatus and methods are provided for interacting light with particles, including but not limited to biological matter such as cells, in unique and highly useful ways. Optophoresis consists of subjecting particles to various optical forces, especially optical gradient forces, and more particularly moving optical gradient forces, so as to obtain useful results. In biology, this technology represents a practical approach to probing the inner workings of a living cell, preferably without any dyes, labels or other markers. In one aspect, an apparatus is provided for collecting optically sorted particles by providing a first surface adapted to support a plurality of particles, an optical illumination system for subjecting the particles to a moving gradient force to cause the separation of the particles from the first surface, and a second adhesive surface for adhering the separated particles to the second surface.

Abstract: Apparatus and methods are provided for interacting light with particles, including but not limited to biological matter such as cells, in unique and highly useful ways. Optophoresis consists of subjecting particles to various optical forces, especially optical gradient forces, and more particularly moving optical gradient forces, so as to obtain useful results. In biology, this technology represents a practical approach to probing the inner workings of a living cell, preferably without any dyes, labels or other markers. In one aspect, a method is provided for reducing forces between a particle and a surface in a system for optically moving particles by providing particles adjacent a first surface, subjecting the particles to a first light intensity pattern to effect sorting of the particles, and subjecting the particles to a second force in an amount and direction to reduce the interaction between the particle and the surface.