Link to the University of Pittsburgh Homepage
Link to the University Library System Homepage Link to the Contact Us Form


Zhao, Rui (2005) DEVICE-INDUCED ERYTHROCYTE DEFORMATION USING M-FLOW VISUALIZATION. Master's Thesis, University of Pittsburgh. (Unpublished)

Primary Text

Download (3MB) | Preview


Implantable cardiovascular devices are commonly used in clinical treatment for end stage cardiovascular devices. However, they may cause device-induced blood damage which can cause serious complications such as hemolysis and thrombosis. Blood damage often occurs within small passages or journals of the flow path. These regions may be associated with hot-spots in which shear stress is excessive and cells may be irreversibly strained. The successful design of these devices relies on efficiently minimizing supra-physiologic shear fields through computational modeling. However the fundamental blood mechanics under these conditions are not yet fully characterized.This study was therefore conducted to elucidate the microscopic mechanics of cellular deformation that underlie shear-induced hemolysis. A micro fluid system was developed to emulate flow environments at hot-spots and provide optical access for microscopic visualization. The flow of red blood cells (RBCs) within micro channels was illuminated by a pair of stroboscopes resulting in a rapid succession of images -- recorded by double-exposure digital CCD camera. Red blood cell motion and deformation dynamics, as well as the surrounding fluid velocity field under various conditions of hematocrit, flow rate were quantitatively measured using particle image velocimetry (PIV) technique.The results show that cells deform rapidly as they approach the inlet, bear the largest deformation at inlet, keep large deformation inside channel and recover as soon as flowing out of exit. Inside channel, cell deformation will reach to a threshold that the cells will not be elongated as shear stress increases. We concluded that the largest possibility for blood damage occurs at the inlet of gaps or clearance in cardiovascular devices, due to the combined effect of extensional stress and shear stress. The combined effect is great on blood mechanical damage in that it can deform the cell to a maximal value in a transient time. The sublethal damage is more likely to happen than the visible rupture of red cells in our experimental situation. Our findings show basic mechanism underlining device-induced blood damage. The methods are proved to be effective and ready to be applied in further design and investigations.


Social Networking:
Share |


Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Zhao, Ruiruz4@pitt.eduRUZ4
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairAntaki, James
Committee MemberRobertson, Anne Mannerob@engr.pitt.eduRBERTSON
Committee MemberKameneva, Marina Vkamenevamv@upmc.eduMARINA
Committee MemberWu,
Date: 28 January 2005
Date Type: Completion
Defense Date: 2 December 2004
Approval Date: 28 January 2005
Submission Date: 8 December 2004
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Institution: University of Pittsburgh
Schools and Programs: Swanson School of Engineering > Bioengineering
Degree: MSBeng - Master of Science in Bioengineering
Thesis Type: Master's Thesis
Refereed: Yes
Other ID:, etd-12082004-112132
Date Deposited: 10 Nov 2011 20:09
Last Modified: 19 Dec 2016 14:38


Monthly Views for the past 3 years

Plum Analytics

Actions (login required)

View Item View Item