Research Areas

In Vivo Flow Cytometry

In vivo flow cytometry, which combines confocal microscopy and flow cytometry, has been developed as a new non-invasive method of detecting and monitoring circulating cells. Cells are tagged with fluorescent dyes conjugated to antibodies specific to white blood cells or tumor specific markers. Alternatively, the cells may be transfected to express a fluorescent protein. As labeled cells flow naturally in the blood, the cells are excited as they traverse one or more laser beams in single file. Fluorescence and scattered photons are collected by one or two detectors. A confocal slit by the detector eliminates background fluorescence, thereby improving the signal to noise ratio.
Current research is focused on the detection and counting of two clinically important cell populations: leukocytes and tumor cells. The number of white blood cells in circulation can indicate the progression of disease as well as the efficacy of treatment; their numbers are typically monitored during infection, organ and bone marrow transplants, chemotherapy and AIDS. In vivo flow cytometry could allow for blood cell analysis without the need to take blood samples. Moreover, since, cancer cells for example are observed without disturbing the host physiology, it can be used to address fundamental questions related to the role of circulating cancer cells during cancer progression and metastasis.

Collaborators:
Tayyaba Hasan, Wellman Center for Photomedicine, Harvard Medical School
Charlotte Kuperwasser, Tufts University School of Medicine, Cell, Molecular & Developmental Biology
Charles Lin, Wellman Center for Photomedicine, Massachusetts General Hospital

Optical schematic of In Vivo Flow Cytometer

Mouse Vasculature
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Abstracts and Conference Proceedings:

1. Georgakoudi I, Solban N, Rice W^g, Lin C, Hasan T. In vivo flow cytometry: A noninvasive method for monitoring circulating cells after PDT. Presented at the Annual Optics East Meeting of the International Society for Optical Engineering. Boston, MA, 23-26 October, 2005.
2. Boutrus S^g, Greiner C^g, Georgakoudi I. Real time detection of circulating cancer cells in a mouse model by a portable in vivo flow cytometer. 26th Annual meeting of the American Society of Lasers in Medicine and Surgery, Boston, MA, April 5-9, 2006. Lasers Surg Med 2006; 83-83 281 Suppl. 18.

1. Georgakoudi I, Solban N, Novak J, Rice W, Hasan T, Lin C. In vivo flow cytometry: A new method for enumerating circulating tumor cells. Cancer Res 2004; 64: 5044-5047.
2. Wei X, Sipkins D, Pitsillides C, Novak J, Georgakoudi I, Lin C. Real-time detection of circulating apoptotic cells by in vivo flow cytometry. Mol Imaging 2005; 4: 415-416.
3. Boutrus S^u, Greiner C^g, Hwu D^u, Chan M, Kuperwasser C, Lin C, Georgakoudi I. A Portable Two-Color In Vivo Flow Cytometer for Real-Time Detection of Fluorescently-Labeled Circulating Cells. JBO Letters 2007; In Press.