New paper in Advanced Science, 2016:

Rapid three-dimensional refractive-index imaging of live cells in suspension without labeling using dielectrophoretic cell rotation

Mor Habaza, Michael Kirschbaum, Christian Guernth-Marschner, Gili Dardikman, Itay Barnea, Rafi Korenstein, Claus Duschl, and Natan T. Shaked

Abstract:

A major challenge in the field of optical imaging of live cells is achieving rapid, three-dimensional (3-D) and noninvasive imaging of isolated cells without labeling. If successful, many clinical procedures involving analysis and sorting of cells drawn from body fluids, including blood, can be significantly improved.  We present a new label-free tomographic interferometry approach that provides rapid capturing of the 3-D refractive index distribution of single cells in suspension. The cells flow in a microfluidic channel, are trapped and rapidly rotated by dielectrophoretic forces in a noninvasive and precise manner. Interferometric projections of the rotated cell are acquired and processed into the cellular 3-D refractive index map.  Uniquely, this approach provides full (360^o) coverage of the rotation angular range on any axis, and knowledge on the viewing angle. Our experimental demonstrations include 3-D, label-free imaging of both large cancer cells and three-types of white blood cells. This approach is expected to be useful for label-free cell sorting, as well as for detection and monitoring of pathological conditions resulting in cellular morphology changes or occurrence of contain cellular types in blood or other body fluids.

(a,b) Refractive-index maps of an MCF-7 cell at the mid-sagittal slice for using a full cell rotation on a single axis (a) and on two axes (b). The arrow indicate details that are clearer when rotating the cell on two axes.  (c,d) 3-D renderings (c) and rendered iso-surface plot (d) of the refractive-index map of the reconstructed refractive index map of an MCF-7 cancer cell. (e-j) Refractive index maps of three types of white blood cells at the mid-axial positions (e-g), and the coinciding rendered iso-surface plots of the refractive-index maps (h-j); (e,h) T cell, see also Supplementary Video 4; (f,i) Monocyte, see also Supplementary Video 5; (g,j) Neutrophil, see also Supplementary Video 6.