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A micro-fluidic study of whole blood behaviour on PMMA topographical nanostructures.

Minelli C, Kikuta A, Tsud N, Ball MD, Yamamoto A - J Nanobiotechnology (2008)

Bottom Line: Although nano-topography has been found to influence cell behaviour, no established method exists to understand and evaluate the effects of nano-topography on polymer-blood interaction.Surface feature size varied from 40 nm to 400 nm and feature height from 5 nm to 50 nm.Whole blood flow rate through the micro-fluidic channels was found to decrease with increasing average surface feature size.

View Article: PubMed Central - HTML - PubMed

Affiliation: International Centre for Young Scientists, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan. c.minelli@imperial.ac.uk.

ABSTRACT

Background: Polymers are attractive materials for both biomedical engineering and cardiovascular applications. Although nano-topography has been found to influence cell behaviour, no established method exists to understand and evaluate the effects of nano-topography on polymer-blood interaction.

Results: We optimized a micro-fluidic set-up to study the interaction of whole blood with nano-structured polymer surfaces under flow conditions. Micro-fluidic chips were coated with polymethylmethacrylate films and structured by polymer demixing. Surface feature size varied from 40 nm to 400 nm and feature height from 5 nm to 50 nm. Whole blood flow rate through the micro-fluidic channels, platelet adhesion and von Willebrand factor and fibrinogen adsorption onto the structured polymer films were investigated. Whole blood flow rate through the micro-fluidic channels was found to decrease with increasing average surface feature size. Adhesion and spreading of platelets from whole blood and von Willebrand factor adsorption from platelet poor plasma were enhanced on the structured surfaces with larger feature, while fibrinogen adsorption followed the opposite trend.

Conclusion: We investigated whole blood behaviour and plasma protein adsorption on nano-structured polymer materials under flow conditions using a micro-fluidic set-up. We speculate that surface nano-topography of polymer films influences primarily plasma protein adsorption, which results in the control of platelet adhesion and thrombus formation.

No MeSH data available.


Related in: MedlinePlus

Microfluidic experiments with washed platelets. Optical images of (A) PMMA2 and (B) PMMA4 coated chips during the flow experiments performed with washed platelets (WP). The images were taken when (1) 20 μL and (2) 80 μL of WP solution had passed through the channels and (3) after chip rinsing. The arrows indicate the flow direction. (C) Statistical distribution of adhered platelets onto the chips having different surface topographies according to Table 1 after rinsing. Each bar represents the average number of platelets counted over 20 SEM images having the same surface area.
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Figure 5: Microfluidic experiments with washed platelets. Optical images of (A) PMMA2 and (B) PMMA4 coated chips during the flow experiments performed with washed platelets (WP). The images were taken when (1) 20 μL and (2) 80 μL of WP solution had passed through the channels and (3) after chip rinsing. The arrows indicate the flow direction. (C) Statistical distribution of adhered platelets onto the chips having different surface topographies according to Table 1 after rinsing. Each bar represents the average number of platelets counted over 20 SEM images having the same surface area.

Mentions: 100 μL of washed platelet solution was flowed through the chip channels exhibiting different topographies. The number of platelets that adhered onto each surface appeared to vary depending on the surface feature size. Figures 5A and 5B show optical images of a portion of the chip surface of PMMA2 and PMMA4 respectively during the blood flow and after the chip was rinsed with NaCl solution. The dots visible on the chip surfaces are the platelets. For the duration of the flow, the density of platelet adherence on PMMA4 is lower than on PMMA2. Chip rinsing does not cause a significant detachment of the platelets from the surface, indicating that they are firmly adhered onto the polymer film. Quantitative investigation of platelet density was performed by SEM. Figure 5C shows the statistical distribution of platelet adhered onto the different topographies. Each histogram bar represents the average number of adhered platelets calculated from 20 SEM images with the same surface area (2.99·103 μm2), while the error bars are the standard deviations of each distribution. The average number of adhered platelets per unit area decreases with increasing feature size. However, close examination of the platelets by SEM did not reveal any morphological difference between them in relation to the different topographies.


A micro-fluidic study of whole blood behaviour on PMMA topographical nanostructures.

Minelli C, Kikuta A, Tsud N, Ball MD, Yamamoto A - J Nanobiotechnology (2008)

Microfluidic experiments with washed platelets. Optical images of (A) PMMA2 and (B) PMMA4 coated chips during the flow experiments performed with washed platelets (WP). The images were taken when (1) 20 μL and (2) 80 μL of WP solution had passed through the channels and (3) after chip rinsing. The arrows indicate the flow direction. (C) Statistical distribution of adhered platelets onto the chips having different surface topographies according to Table 1 after rinsing. Each bar represents the average number of platelets counted over 20 SEM images having the same surface area.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2279145&req=5

Figure 5: Microfluidic experiments with washed platelets. Optical images of (A) PMMA2 and (B) PMMA4 coated chips during the flow experiments performed with washed platelets (WP). The images were taken when (1) 20 μL and (2) 80 μL of WP solution had passed through the channels and (3) after chip rinsing. The arrows indicate the flow direction. (C) Statistical distribution of adhered platelets onto the chips having different surface topographies according to Table 1 after rinsing. Each bar represents the average number of platelets counted over 20 SEM images having the same surface area.
Mentions: 100 μL of washed platelet solution was flowed through the chip channels exhibiting different topographies. The number of platelets that adhered onto each surface appeared to vary depending on the surface feature size. Figures 5A and 5B show optical images of a portion of the chip surface of PMMA2 and PMMA4 respectively during the blood flow and after the chip was rinsed with NaCl solution. The dots visible on the chip surfaces are the platelets. For the duration of the flow, the density of platelet adherence on PMMA4 is lower than on PMMA2. Chip rinsing does not cause a significant detachment of the platelets from the surface, indicating that they are firmly adhered onto the polymer film. Quantitative investigation of platelet density was performed by SEM. Figure 5C shows the statistical distribution of platelet adhered onto the different topographies. Each histogram bar represents the average number of adhered platelets calculated from 20 SEM images with the same surface area (2.99·103 μm2), while the error bars are the standard deviations of each distribution. The average number of adhered platelets per unit area decreases with increasing feature size. However, close examination of the platelets by SEM did not reveal any morphological difference between them in relation to the different topographies.

Bottom Line: Although nano-topography has been found to influence cell behaviour, no established method exists to understand and evaluate the effects of nano-topography on polymer-blood interaction.Surface feature size varied from 40 nm to 400 nm and feature height from 5 nm to 50 nm.Whole blood flow rate through the micro-fluidic channels was found to decrease with increasing average surface feature size.

View Article: PubMed Central - HTML - PubMed

Affiliation: International Centre for Young Scientists, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan. c.minelli@imperial.ac.uk.

ABSTRACT

Background: Polymers are attractive materials for both biomedical engineering and cardiovascular applications. Although nano-topography has been found to influence cell behaviour, no established method exists to understand and evaluate the effects of nano-topography on polymer-blood interaction.

Results: We optimized a micro-fluidic set-up to study the interaction of whole blood with nano-structured polymer surfaces under flow conditions. Micro-fluidic chips were coated with polymethylmethacrylate films and structured by polymer demixing. Surface feature size varied from 40 nm to 400 nm and feature height from 5 nm to 50 nm. Whole blood flow rate through the micro-fluidic channels, platelet adhesion and von Willebrand factor and fibrinogen adsorption onto the structured polymer films were investigated. Whole blood flow rate through the micro-fluidic channels was found to decrease with increasing average surface feature size. Adhesion and spreading of platelets from whole blood and von Willebrand factor adsorption from platelet poor plasma were enhanced on the structured surfaces with larger feature, while fibrinogen adsorption followed the opposite trend.

Conclusion: We investigated whole blood behaviour and plasma protein adsorption on nano-structured polymer materials under flow conditions using a micro-fluidic set-up. We speculate that surface nano-topography of polymer films influences primarily plasma protein adsorption, which results in the control of platelet adhesion and thrombus formation.

No MeSH data available.


Related in: MedlinePlus