David Scadden,
MD, Gerald and Darlene Jordan Professor of Medicine, Harvard University;
Co-Director, Harvard Stem Cell Institute; Co-Chair; Department of Stem
Cell and Regenerative Biology, Harvard University; Director, Center
for Regenerative Medicine, Massachusetts General Hospital,
dscadden@partners.org
Moderator: Charles A. Vacanti,
MD, Anesthesiologist-in-Chief, Leroy D. Vandam/Benjamin G. Covino Professor
of Anaesthesia, Harvard Medical School; Director, Laboratories for Tissue
Engineering and Regenerative Medicine, Brigham and Women's Hospital,
cvacanti@partners.org
David Scadden will help us explore the regulation of stem cells
by their microenvironment focusing on the hematopoietic system as a
model. Deconstructing the elements of a naturally occurring niche will
be discussed and how that information can be used in developing therapeutics
will be presented. Finally, a word of caution will be introduced by
an example of how a dysfunctional niche can lead to neoplasia.
Nudging Cells Using Molecular Interactions: Towards Label-free Cell Rolling Separation
Rohit Karnik, PhD, d’Arbeloff Assistant Professor, Department of Mechanical Engineering, Massachusetts Institute of Technology, karnik@mit.eduModerator: Jeffrey Borenstein, PhD, Distinguished Member of the Technical Staff at the Charles Stark Draper Laboratory; Co-Program Leader, Tissue Engineering, CIMIT, jborenstein@draper.com
Separation of cells using surface receptors typically relies on labeling with fluorescent dyes or magnetic beads, or capture on surfaces. While these approaches are extremely useful, it is desirable to minimize sample processing for point-of-care diagnostics and for therapeutic purposes. Rohit Karnik's lab is exploring a new method for label-free cell separation. This approach is based on the team's discovery that asymmetrically patterned receptor edges have the ability to nudge cells flowing over the patterns so that they travel at an angle to the direction of fluid flow. This effect relies on transient adhesive interactions that typically occur during cell rolling, a physiological phenomenon exhibited by various cell types including leukocytes, cancer cells and stem cells. As the cell rolls on a surface in a fluid flow, bonds are formed at the leading edge of the cell and are broken at the trailing edge. Combining cell rolling with asymmetric receptor patterning enables control of the trajectories of the rolling cells, and opens the possibility for label-free cell separation where a stream of cells could be separated and collected in a continuous-flow manner in a simple device with minimal to no sample processing. Dr. Karnik will present results with rolling of HL-60 cells on patterned P-selectin receptors. He will also discuss progress on using this edge effect to realize a microfluidic device to separate cells and our efforts on modeling of the cell rolling phenomenon. Future development of this technology may lead to simple, label-free methods for detection of systemic inflammation, blood counts, isolation of cancer cells, and fractionation of stem cells.
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