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BEGIN:VEVENT
DTSTAMP:20260817T140741Z
LAST-MODIFIED:20121116T203436Z
DTSTART:20070223T170000Z
DTEND:20070223T190000Z
UID:event75@bu.edu
URL:http://physics.bu.edu/internal/events/show/75
SUMMARY:Nanoscale cell membrane fluctuations quantified by optical interfer
	ometry
DESCRIPTION:Featuring Gabriel Popescu\, G.R. Harrison Spectroscopy Laborato
	ry\, MIT\n\nPart of the Biophysics/Condensed Matter Seminar Series.\n\nRed 
	blood cells (RBCs) must withstand large deformations during multiple passag
	es through microvasculature. This essential ability is diminished with age 
	and disease. Therefore\, quantifying the mechanical properties of live RBC 
	membranes provides insight into a variety of problems regarding the interpl
	ay of cell structure\, dynamics\, and function. RBC thermal fluctuations ("
	flickering") have been studied for more than a century as they offer a pote
	ntial window into these phenomena. Nevertheless\, quantifying these motions
	 is experimentally challenging\, as they develop at the nanometer and milli
	second scales across the entire cell. Thus\, reliable spatial and temporal 
	data are currently limitted. Here we use diffraction phase microscopy\, a n
	ovel\, highly sensitive optical imaging technique\, to quantify the flicker
	ing of RBC membranes. This method relies on quantifying with sub-nanometer 
	accuracy the optical path-length shift associated with the light passing th
	rough the cell. The static (spatial) behavior of the membrane displacements
	 allow for the first time extracting the effective membrane tension\, which
	 is modulated by the cell cytoskeleton. The dynamic analysis reveals signif
	icant properties of both temporal and spatial correlations of the membrane 
	motions. We show that these correlations can be accounted for by the viscoe
	lastic properties of the cell membrane\, which strongly correlated with cel
	l morphology. We believe that this type of investigation promises to provid
	e a better understanding of diseases such as malaria and sickle cell anemia
	. Furthermore\, understanding the RBC membrane behavior will be important i
	n studying the membrane of other cell types\, for which RBCs are convenient
	 models.
LOCATION:SCI 352\, 590 Commonwealth Avenue\, 02215
STATUS:CONFIRMED
CLASS:PUBLIC
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