The separation or sorting of cellular and colloidal particles is currently a central topics of research. In this chapter, we give an overview of the range of optical methods for cell sorting. We begin with an overview of fluorescence and magnetically activated cell sorting. We progress to describing methods at the microfluidic scale level particularly those exploiting optical forces. We distinguish between what we term passive and active schemes for sorting. Optical forces pertinent to the sorting schemes are described, notably the gradient force and the optical radiation pressure (or scattering force). We discuss some of the most recent advances. This includes techniques without fluid flow where we have either stationary or moving light patterns to initiate separation. Further methods have shown how using an externally driven flow either counter-propagating against a light field (optical chromatography) or over a periodic light pattern (an optical potential energy landscape) may result in the selection of particles and cells based on physical attributes such as size and refractive index. We contrast these schemes with the field of dielectrophoresis where electric field gradients may separate cells and also briefly mention the upcoming area of light-induced dielectrophoresis which marries the reconfigurability of optical fields with the power of dielectrophoresis.
|Title of host publication
|Laser Manipulation of Cells and Tissues
|Michael Berns, Karl Otto Greulich
|Number of pages
|Published - 2007
|Methods in Cell Biology
Bibliographical noteFunding Information:
We thank colleagues in all of our groups for useful discussions on the topics of separation and sorting and Dr. Frank Gunn‐Moore for reading the chapter. We acknowledge support from the UK Engineering and Physical Sciences Research Council, Scottish Higher Education Funding Council, and the ATOM‐3D network (contract number 508952) funded under the NEST Program of the European Commission framework 6 program, PZ acknowledges the support of the Centre of Modern Optics (LC06007) under the Ministry of Education, Youth, and Sports of the Czech Republic and the ISI Institutional research plan (AV0Z20650511).
All Science Journal Classification (ASJC) codes
- Cell Biology