KUSOM Research Meeting, January 24th, 2012 (Dr. Kerem Pekkan)
KOÇ UNIVERSITY SCHOOL OF MEDICINE
SEMINAR
Tuesday, January 24th, 2012
******************************************************************
Speaker : Dr. Kerem Pekkan; Assistant Professor in Carnegie Mellon University’s Biomedical and Mechanical Engineering Departments
Title : High-speed multi-phase blood cell flow using confocal scanning microscopy for the development of next-generation blood damage models
Time : 16.00 (Refreshments will be served at 15.45)
Place : SOS B 21
High-speed multi-phase blood cell flow using confocal scanning microscopy for the development of next-generation blood damage models
Abstract: Measurement of multi-phase micro-scale morphology and fluid flow in the advanced microscopy environment represents a major step toward assessing blood element damage in medical devices and understanding the developmental role of hemodynamics in congenital heart defects. For improved medical devices with very low blood damage and platelet activation, three-dimensional, time-lapsed cellular deformation and fluid-induced mechanical red blood cell (RBC) loading must be quantified. In particular, investigating near-wall regions of high flow blood-wetted micro-components in cardiovascular devices is critical. Unfortunately, most relevant prior research is limited to very low flow speeds and to non-physiologic hematocrit (Ht) levels, due to limited optical access at higher RBC concentrations. Towards this objective a time-resolved, confocal microPIV technique that simultaneously measures velocities of high Ht (48%) human RBC and the plasma with high temporal (16,000 Hz) and spatial resolution in in vitro micro-fabricated channels has been developed. This technique integrates advanced confocal microscopy with in-house long wavelength fluorescent dyes. For the first time in literature, confocal velocimetry allowed deep measurements in optically opaque physiological high-Ht blood where measures of cell-cell and cell-plasma interactions (tracked with sub-micron fluorescent particles) and membrane phase unsteadiness have been reported. The method is further applied to pulsatile great vessel microcirculation using transgenically labeled zebrafish embryonic blood and endothelial cells, where average velocities can reach up to ~5 mm/s through short vessel sections, requiring advanced high-speed imaging. We demonstrated that individual RBC flow and dynamic crowded cell morphology can be acquired in microscopic aortic arches with high spatial resolution and record temporal resolution (resulting 175 full frames/sec). The limitations of the state-of-the art confocal hardware and configurations will also be reviewed.
