Time-of-flight optophoresis analysis of live whole cells in microfluidic channels.

Optophoresis is a non-invasive cell analysis technique that is based on the interaction of live whole cells with optical gradient fields, typically generated by a near-infrared laser. The magnitude of the interaction depends upon the intrinsic physical properties of the cells, such as their refractive index, composition, size, and morphology. Time-of-flight (TOF) optophoresis is an implementation of this technique in a microfluidic environment.

Optical forces for noninvasive cellular analysis.

A novel, noninvasive measurement technique for quantitative cellular analysis is presented that utilizes the forces generated by an optical beam to evaluate the physical properties of live cells in suspension. In this analysis, a focused, near-infrared laser line with a high cross-sectional intensity gradient is rapidly scanned across a field of cells, and the interaction of those cells with the beam is monitored. The response of each cell to the laser depends on its size, structure, morphology, composition, and surface membrane properties; therefore, with this technique, cell populations of different type, treatment, or biological state can be compared.