Featured Research

from universities, journals, and other organizations

Blood is thicker than water – and blood plasma is, too

Date:
February 18, 2013
Source:
University Saarland
Summary:
Blood flows differently than water. Anyone who has ever cut themselves knows that blood flows viscously and rather erratically. The similarity between blood and ketchup is something not only filmmakers are aware of. Experts refer to these materials as “non-Newtonian fluids,” of which ketchup and blood are prime examples. These fluids have flow properties that change depending on conditions, with some becoming more viscous, while others become less viscous.

Blood flows differently than water. Anyone who has ever cut themselves knows that blood flows viscously and rather erratically. The similarity between blood and ketchup is something not only filmmakers are aware of. Experts refer to these materials as "non-Newtonian fluids," of which ketchup and blood are prime examples. These fluids have flow properties that change depending on conditions, with some becoming more viscous, while others become less viscous. Blood (like ketchup) is a "shear thinning fluid" that becomes less viscous with increasing pressure and it is this that allows blood to flow into the narrowest of capillaries. The flow properties of water are, in contrast, essentially constant.

Up until now it has been assumed that the special flow characteristics exhibited by blood were mainly due to the presence of the red blood cells, which account for about 45 percent of the blood's volume. Blood plasma was generally regarded simply as a spectator that played no active role. For decades, researchers have assumed that blood plasma flows like water. After all, plasma, the liquid in which the blood cells are suspended, consists to 92 percent of water. But results from researchers at Saarland University and at the University of Pennsylvania have now shown that plasma is a very special fluid that plays a crucial part in determining how blood flows. The results demonstrate that blood plasma is itself a non-Newtonian fluid.

According to the study's findings, the complex flow behavior of blood plasma could play a crucial role with respect to vascular wall deposits, aneurysms or blood clots. The results from this research may well help to improve computer simulations of this kind of pathological process.

The research team around experimental physicist Christian Wagner and engineer Paulo E. Arratia have studied the flow dynamics of blood experimentally. The work at Saarland University involved experiments in which the blood plasma was allowed to form drops inside a specially built apparatus equipped with high-speed cameras fitted with high-resolution microscope lenses to analyze drop formation. "Our experiments showed that the blood plasma forms threads, that is, it exhibits an extensional viscosity, which is something we do not observe in water," explained Professor Wagner. The plasma shows "viscoelastic" properties, which means that it exhibits both viscous and elastic behavior when deformed, forming threads that are typical of non-Newtonian fluids.

The studies by Professor Arratia and his team at the University of Pennsylvania involved a microfluidic approach in which they developed a model of a microvascular system in order to study the flow properties of blood plasma. Their measurements showed that blood plasma exhibits a flow behavior different to that of water and that plasma can demonstrate a substantially higher flow resistance. "An important part of our study was developing microfluidic instruments sensitive enough to pick up the small differences in viscosity that are the signature of non-Newtonian fluids," explained Professor Arratia.

Experiments performed by Professor Wagner's team in Saarbrόcken also showed that blood plasma influences the creation of vortices in flowing blood. These vortices may facilitate the formation of deposits on blood vessel walls which could influence blood clot formation. In one of their experiments, the research team let plasma flow through a narrow channel of the kind found in stenotic (constricted) arteries or in a stent (a medical implant inserted into constricted blood vessels). The vortical structures were detected at the end, but also at the entrance, of the narrow channel and their formation is a direct result of the viscoelastic flow properties of blood plasma.

The research at Saarland University was performed within the Research Training Group "Structure Formation and Transport in Complex Systems" funded by the German Research Foundation (DFG). The research at the University of Pennsylvania was supported by the US National Science Foundation -- CBET- 0932449.

Original publication:

M. Brust, C. Schaefer, R. Doerr, L. Pan, M. Garcia, P. E. Arratia, and C. Wagner (2013):

"Rheology of human blood plasma: Viscoelastic versus Newtonian behavior," Phys. Rev. Lett., 110, 078305 (2013)

DOI: 10.1103/PhysRevLett.110.078305

http://link.aps.org/doi/10.1103/PhysRevLett.110.078305

Physics (http://physics.aps.org/): Focus: http://physics.aps.org/articles/v6/18 (video)

Contact:

Professor Dr. Christian Wagner

Department of Experimental Physics, Saarland University

Tel.: 0049 (0)681 302-3003 or -2416; E-mail: c.wagner@mx.uni-saarland.de

http://agwagner.physik.uni-saarland.de/

Professor Paulo E. Arratia

Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania

Tel.: 001 215 746-2174; E-mail: parratia@seas.upenn.edu

www.seas.upenn.edu/~parratia

Press photographs are available at www.uni-saarland.de/pressefotos and can be used at no charge. Please read and comply with the conditions of use.

Note for radio journalists: Studio-quality telephone interviews can be conducted with researchers at Saarland University using broadcast audio IP codec technology. Interview requests should be addressed to the university's Press and Public Relations Office (+49 (0)681 302-2601).


Story Source:

The above story is based on materials provided by University Saarland. Note: Materials may be edited for content and length.


Journal Reference:

  1. M. Brust, C. Schaefer, R. Doerr, L. Pan, M. Garcia, P. E. Arratia, and C. Wagner. Rheology of human blood plasma: Viscoelastic versus Newtonian behavior. Phys. Rev. Lett, 110, 078305 (2013) DOI: 10.1103/PhysRevLett.110.078305

Cite This Page:

University Saarland. "Blood is thicker than water – and blood plasma is, too." ScienceDaily. ScienceDaily, 18 February 2013. <www.sciencedaily.com/releases/2013/02/130218092505.htm>.
University Saarland. (2013, February 18). Blood is thicker than water – and blood plasma is, too. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/2013/02/130218092505.htm
University Saarland. "Blood is thicker than water – and blood plasma is, too." ScienceDaily. www.sciencedaily.com/releases/2013/02/130218092505.htm (accessed July 28, 2014).

Share This




More Health & Medicine News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

$15B Deal on Vets' Health Care Reached

$15B Deal on Vets' Health Care Reached

AP (July 28, 2014) — A bipartisan deal to improve veterans health care would authorize at least $15 billion in emergency spending to fix a veterans program scandalized by long patient wait times and falsified records. (July 28) Video provided by AP
Powered by NewsLook.com
Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) — Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) Video provided by AP
Powered by NewsLook.com
West Africa Gripped by Deadly Ebola Outbreak

West Africa Gripped by Deadly Ebola Outbreak

AFP (July 28, 2014) — The worst-ever outbreak of the deadly Ebola epidemic grips west Africa, killing hundreds. Duration: 00:48 Video provided by AFP
Powered by NewsLook.com
Trees Could Save More Than 850 Lives Each Year

Trees Could Save More Than 850 Lives Each Year

Newsy (July 27, 2014) — A national study conducted by the USDA Forest Service found that trees collectively save more than 850 lives on an annual basis. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins