| 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. |