Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


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

Joint press release from Saarland University and the University of Pennsylvania

A German-American research team has succeeded in demonstrating that blood plasma has a much greater effect on how blood flows than was previously thought. The groups led by Christian Wagner (Saarland University, Germany) and Paulo E. Arratia (University of Pennsylvania, USA) have refuted the view, held for decades, that plasma behaves like water. Blood plasma is far more elastic and viscous than previously thought and, like ketchup, its flow properties depend on the applied pressure.

The results are significant because they can help to improve our understanding of medical conditions, such as thrombosis, aneurysms and arteriosclerosis. The research team is publishing its results in Physical Review Letters and the American Physical Society has highlighted the work on its Physics website (, placing it on the Focus List of important physics news.

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 Saarbrücken 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
Physics (
Focus: (video)
Professor Dr. Christian Wagner
Department of Experimental Physics, Saarland University
Tel.: 0049 (0)681 302-3003 or -2416; E-mail:
Professor Paulo E. Arratia
Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania
Tel.: 001 215 746-2174; E-mail:
Press photographs are available at 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).

Friederike Meyer zu Tittingdorf | idw
Further information:

More articles from Life Sciences:

nachricht Biologists unravel another mystery of what makes DNA go 'loopy'
16.03.2018 | Emory Health Sciences

nachricht Scientists map the portal to the cell's nucleus
16.03.2018 | Rockefeller University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Locomotion control with photopigments

Researchers from Göttingen University discover additional function of opsins

Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...

Im Focus: Surveying the Arctic: Tracking down carbon particles

Researchers embark on aerial campaign over Northeast Greenland

On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...

Im Focus: Unique Insights into the Antarctic Ice Shelf System

Data collected on ocean-ice interactions in the little-researched regions of the far south

The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...

Im Focus: ILA 2018: Laser alternative to hexavalent chromium coating

At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.

When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...

Im Focus: Radar for navigation support from autonomous flying drones

At the ILA Berlin, hall 4, booth 202, Fraunhofer FHR will present two radar sensors for navigation support of drones. The sensors are valuable components in the implementation of autonomous flying drones: they function as obstacle detectors to prevent collisions. Radar sensors also operate reliably in restricted visibility, e.g. in foggy or dusty conditions. Due to their ability to measure distances with high precision, the radar sensors can also be used as altimeters when other sources of information such as barometers or GPS are not available or cannot operate optimally.

Drones play an increasingly important role in the area of logistics and services. Well-known logistic companies place great hope in these compact, aerial...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

International Virtual Reality Conference “IEEE VR 2018” comes to Reutlingen, Germany

08.03.2018 | Event News

Latest News

Wandering greenhouse gas

16.03.2018 | Earth Sciences

'Frequency combs' ID chemicals within the mid-infrared spectral region

16.03.2018 | Physics and Astronomy

Biologists unravel another mystery of what makes DNA go 'loopy'

16.03.2018 | Life Sciences

Science & Research
Overview of more VideoLinks >>>