CIPS/OSA Brown Bag Seminar Series

Thursday, November 29, 2007

12 noon , RLE Haus Conf. Room 36-428

"Intuitive, Image-based Sorting of Mammalian Cells Using OPTO-FLUidic Cell Sorting (OPTO-FLUCS)"

Joseph Kovac

Presently, there is a strong tradeoff between the ability to image cells and the ability to sort them.  Fluorescence activated cell sorting (FACS) allows high-throughput sorting1, but cannot predicate sorts on fluorescence localization, temporal fluorescence dynamics, and other characteristics observable using microscopy.  Laser capture microdissection2 (LCM) allows imaging of cells before selection, enabling image-based sorts.  However, many LCM systems adapted to viable cell sorting require growth of cells on proprietary films and, as with FACS, the purchase of highly specialized, expensive equipment often found in core facilities rather than individual labs.

We present an optofluidic platform that allows cells to be both imaged and sorted in an intuitive, user-friendly manner.  Our approach3 is compatible with standard automated fluorescence microscopes increasingly found in many labs.  Our device consists of a microfluidic flow chamber with a > 10,000-site microwell array patterned into the chamber floor that enables passive loading, trapping, and observation of populations of cells using microscopy.  We release cells of interest by focusing an infrared laser beam onto target cells, levitating them from their microwells via the optical scattering force into a collection flow stream.  We demonstrate sorting predicated on image-based whole-cell fluorescence as well as fluorescence localization. We have achieved up to 155-fold enrichment of desired cell populations and up to 89% sorted population purity.  Furthermore, results from a direct cell viability test and studies from optical manipulation literature suggest that cells remain viable following our method.