Affiliations: McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA | Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA | Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA | Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA
Note: [] Dr. Marhefka's current affiliation is National Institute of Standards and Technology, Gaithersburg, MD, USA.
Note: [] Address for correspondence: Dr. Marina Kameneva, 450 Technology Dr., Suite 300, Pittsburgh, PA 15219, USA. Tel.: +1 412 624 5281 (office); +1 412 624 5283 (laboratory); Fax: +1 412 624 5363; E-mail: kamenevamv@upmc.edu.
Abstract: The accumulation of platelets near the blood vessel wall or artificial surface is an important factor in the cascade of events responsible for coagulation and/or thrombosis. In small blood vessels and flow channels this phenomenon has been attributed to the blood phase separation that creates a red blood cell (RBC)-poor layer near the wall. We hypothesized that blood soluble drag-reducing polymers (DRP), which were previously shown to lessen the near-wall RBC depletion layer in small channels, may consequently reduce the near-wall platelet excess. This study investigated the effects of DRP on the lateral distribution of platelet-sized fluorescent particles (diam. = 2 μm, 2.5 × 108/ml) in a glass square microchannel (width and depth = 100 μm). RBC suspensions in PBS were mixed with particles and driven through the microchannel at flow rates of 6–18 ml/h with and without added DRP (10 ppm of PEO, MW = 4500 kDa). Microscopic flow visualization revealed an elevated concentration of particles in the near-wall region for the control samples at all tested flow rates (between 2.4 ± 0.8 times at 6 ml/h and 3.3 ± 0.3 times at 18 ml/h). The addition of a minute concentration of DRP virtually eliminated the near-wall particle excess, effectively resulting in their even distribution across the channel, suggesting a potentially significant role of DRP in managing and mitigating thrombosis.
Keywords: Drag-reducing polymers, platelet margination, microchannels, red blood cell traffic
DOI: 10.3233/BIR-2010-0570
Journal: Biorheology, vol. 47, no. 3-4, pp. 193-203, 2010
