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Date: Wednesday, October 15, 2013
Time: 11:00 am
Speaker: Paul Abbyad, Santa Clara University
Title: Microfluidic Droplet Arrays for the Study of Red Blood Cell Sickling
Location: 67-3111       Chemla room

We have developed a novel microfluidic device to study individual red blood cells in droplet arrays. This is a two-phase system where aqueous droplets containing cells are produced and transported in inert carrier oil. Droplets are anchored into an array by the reduction in their surface energy as they enter into microfabricated depressions. Thus, microdroplets are anchored and arranged in a 2-dimensional array against the flow of the carrier oil. The perfluorinated carrier oil has a high solubility for gases and is used as both a sink and source for oxygen exchange with the anchored droplets. By varying the oxygen concentration of the flowing oil, the oxygen concentration of a droplet is controlled to simulate the oxygen cycling in blood flow. At low oxygen concentrations, red blood cells from sickle cell patients undergo reversible, sickling, or deformation, due to polymerization of hemoglobin in the cell. By oscillating the oxygen concentration, cycles of sickling and de-sickling of individual red blood cells are observed in real-time. Polarization microscopy allows for the sensitive detection of intracellular hemoglobin fibers. This device allows the study of the cumulative impact of repeated deformation on cells, such as membrane damage and cell dehydration, that is believed to be central to disease pathology.