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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

Whole blood flow rate in micro-fluidic experiments. Volume flow rate of (A) NaCl solution and (B) whole human blood measured with the MC-FAN on micro-fluidic chips coated with PMMA films presenting different surface topographies, as reported in Table 1.
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Figure 3: Whole blood flow rate in micro-fluidic experiments. Volume flow rate of (A) NaCl solution and (B) whole human blood measured with the MC-FAN on micro-fluidic chips coated with PMMA films presenting different surface topographies, as reported in Table 1.

Mentions: X-ray Photoelectron Spectroscopy (XPS) measurements on samples prepared as PMMA1 (pure PMMA), PMMA2, PMMA3, PMMA4 and on pure PS films were performed to study the chemical composition of the films at the polymer/blood interface. Figure 2B shows the typical XPS C1s spectrum of a flat PMMA film (PMMA1). The C1s spectrum of pure PMMA is the result of the convolution of four peaks: the hydrocarbon (C-C/C-H) at a binding energy of 285.0 eV, the β-shifted carbon (due to their juxtaposition to O-C=O groups) at 285.7 eV, the methoxy group carbon at 286.8 eV and the carbon in the ester group at 289.1 eV [24]. The C1s spectrum of pure PS (Fig. 2C) includes a main hydrocarbon peak at binding energy of 285.0 eV. Figure 3D shows the typical C1s spectra of a structured PMMA surface. For comparison, the spectrum relative to pure PMMA is also shown (dashed line). As the ester peak at 289.1 eV contains contribution solely from PMMA, the spectrum of pure PMMA was normalized to the spectrum of each structured PMMA film to overlap the peaks relative to the ester group. From this the difference between the spectra was computed. In the case of the PMMA3 surface, this difference is shown in grey in Figure 2D and is attributed to the presence of PS hydrocarbon groups at or close to the surface. Computational analysis of the XPS spectra allowed the calculation of the composition of a 10 nm-thick layer of the polymer film at the polymer/air interface. PMMA was found to constitute (84 ± 16)%, (77 ± 15)% and (71 ± 14)% of respectively sample PMMA2, PMMA3 and PMMA4 films.


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)

Whole blood flow rate in micro-fluidic experiments. Volume flow rate of (A) NaCl solution and (B) whole human blood measured with the MC-FAN on micro-fluidic chips coated with PMMA films presenting different surface topographies, as reported in Table 1.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: Whole blood flow rate in micro-fluidic experiments. Volume flow rate of (A) NaCl solution and (B) whole human blood measured with the MC-FAN on micro-fluidic chips coated with PMMA films presenting different surface topographies, as reported in Table 1.
Mentions: X-ray Photoelectron Spectroscopy (XPS) measurements on samples prepared as PMMA1 (pure PMMA), PMMA2, PMMA3, PMMA4 and on pure PS films were performed to study the chemical composition of the films at the polymer/blood interface. Figure 2B shows the typical XPS C1s spectrum of a flat PMMA film (PMMA1). The C1s spectrum of pure PMMA is the result of the convolution of four peaks: the hydrocarbon (C-C/C-H) at a binding energy of 285.0 eV, the β-shifted carbon (due to their juxtaposition to O-C=O groups) at 285.7 eV, the methoxy group carbon at 286.8 eV and the carbon in the ester group at 289.1 eV [24]. The C1s spectrum of pure PS (Fig. 2C) includes a main hydrocarbon peak at binding energy of 285.0 eV. Figure 3D shows the typical C1s spectra of a structured PMMA surface. For comparison, the spectrum relative to pure PMMA is also shown (dashed line). As the ester peak at 289.1 eV contains contribution solely from PMMA, the spectrum of pure PMMA was normalized to the spectrum of each structured PMMA film to overlap the peaks relative to the ester group. From this the difference between the spectra was computed. In the case of the PMMA3 surface, this difference is shown in grey in Figure 2D and is attributed to the presence of PS hydrocarbon groups at or close to the surface. Computational analysis of the XPS spectra allowed the calculation of the composition of a 10 nm-thick layer of the polymer film at the polymer/air interface. PMMA was found to constitute (84 ± 16)%, (77 ± 15)% and (71 ± 14)% of respectively sample PMMA2, PMMA3 and PMMA4 films.

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