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Hemolysis caused by surface roughness under shear flow.
Osamu Maruyama1, Yusuke Numata, Masahiro Nishida
1Artificial Organ and Biomaterial Group, Institute for Human Science and Biomedical Engineering, National Institute of Advanced Industrial Science and Technology (AIST), 1-2-1 Namiki, Tsukuba, Ibaraki 305-8564, Japan. osamu.maruyama@aist.go.jp
Summary
Surface roughness on blood-contacting materials can cause hemolysis, the rupture of red blood cells. This study identified a roughness threshold between 0.4 and 0.8 micrometers, indicating that increased shear stress from roughness is the primary cause.
Area of Science:
- Biomaterials science
- Hemodynamics
- Medical device engineering
Background:
- Hemolysis is a critical concern in blood-contacting medical devices.
- Previous studies often used pumped circuits, which may not accurately replicate in vivo conditions.
- Understanding the relationship between surface roughness and hemolysis is essential for device design.
Purpose of the Study:
- To investigate the relationship between blood contact surface roughness and hemolysis under controlled laminar shear flow.
- To determine the threshold arithmetic mean roughness (Ra) value that induces hemolysis.
- To evaluate the role of shear stress in roughness-induced hemolysis.
Main Methods:
- Utilized a rotational shear stressor to apply constant shear flow to roughened surfaces.
- Machine-processed 1.8% of blood contact area to achieve arithmetic mean roughness (Ra) values from 0.4 to 9.2 micrometers.
- Applied a shear load for 30 minutes at a shear flow rate of 3750 s(-1).
Main Results:
- Identified a threshold Ra value between 0.4 and 0.8 micrometers for the induction of hemolysis.
- Demonstrated that higher shear stress, resulting from surface roughness, is a significant factor in hemolysis.
- Quantified hemolysis levels directly under constant shear flow conditions.
Conclusions:
- Surface roughness significantly impacts hemolysis, with a critical threshold identified.
- High shear stress generated by surface irregularities is the primary driver of roughness-induced hemolysis.
- The findings provide crucial data for designing safer blood-contacting medical devices.