Einstein's Tea Leaves Inspire New Blood Separation Technique

January 16, 2007

Scientists at Monash University in Australia have developed a process for rapidly and efficiently separating blood plasma at the microscopic level without any moving parts, potentially allowing doctors to do blood tests without sending samples to a laboratory.

The new method uses the same principle that causes tea leaves to accumulate at the center of the bottom in a stirred teacup, a phenomenon first explained by Einstein in the 1920s.

The research was done by Drs. Dian R. Arifin, Leslie Y. Yeo and James R. Friend, of the Monash University’s Micro/Nanophysics Research Laboratory. Their findings were published in the current issue of the new open-access journal Biomicrofluidics.

Separating blood plasma from red blood cells, proteins and other microscopic particles is an essential step in many common medical tests, including those for cholesterol levels, drugs in athletes, blood types in donors and glucose levels in diabetics. Current testing requires samples to be taken in a doctor's office and sent off to a laboratory and analyzed with a large centrifuge, a process that can take several days.

In the new method, a tiny amount of blood enters a fluid chamber, and a needle tip is placed close to the surface of the blood at an angle. A voltage is applied to the needle, generating ions around its tip that repel the oppositely charged ions close to it. This creates an airflow known as "ionic wind" that sweeps across the surface of the blood, causing it to circulate. The microscopic particles in the blood travel in a downward spiral because of the needle’s angle relative to the surface.

When the fluid begins to circulate, one might intuitively expect the microscopic particles such as red blood cells would be pulled to the outside wall of the chamber owing to centrifugal force. But because of a phenomenon called the "tea leaf paradox," the particles are instead pulled inward near the bottom of the chamber. Einstein proposed an explanation to this phenomenon in 1926 when he noticed that tea leaves collected at the center of the bottom of a stirred teacup instead of being expelled outward.

The tiny chamber of blood, like the teacup, is a cylinder of liquid that is rotated at the top while the base remains stationary. To satisfy a zero-velocity condition at the base, an inward force near the bottom of the liquid is generated, suppressing the centrifugal force there. Thus the microscopic particles spiral inward toward the bottom of the chamber like a miniature tornado, leaving a clear layer of plasma above.

Yeo anticipates the technology could be incorporated into a chip roughly the size of a credit card. He said the devices could be produced cheaply with current manufacturing techniques -- about 50 cents per chip -- but could still be five to 10 years away from mass production.

Article: Microfluidic blood plasma separation via bulk electrohydrodynamic flows, Biomicrofluidics 1, 014103 (January-March 2007), accessible at link.aip.org/link/?bmf/1/014103

Source: American Institute of Physics

Explore further: Hospitals ramp up hyperbaric therapy for diabetics, despite concerns

Related Stories

Hospitals ramp up hyperbaric therapy for diabetics, despite concerns

June 29, 2017
The Villages Regional Hospital did not sweat its decision to add hyperbaric oxygen therapy in 2013.

Patients with open wounds get unproven treatments

August 3, 2017
Carol Emanuele beat cancer. But for the past two years, the Philadelphia woman has been fighting her toughest battle yet. She has an open wound on the bottom of her foot that leaves her unable to walk and prone to deadly ...

'Corkscrew' shape of blood flow in heart's upper chamber may signal lower stroke risk

November 2, 2016
Using specialized CT scans of a healthy heart and one with heart disease, a team of Johns Hopkins cardiologists and biomedical engineers say they've created computer models of the "shape" of blood flow through the heart's ...

New technique to improve blood flow in children born with one functional ventricle shows promise in pilot study

July 3, 2012
(Medical Xpress) -- Two in every thousand babies born in the United States start life with just one functional ventricle, or pumping chamber, instead of the normal two. These babies typically undergo a series of two or three ...

The typhoid fever pathogen uses a cloaking mechanism to evade neutrophil neutralization

August 7, 2014
Typhoid fever is caused by systemic (body-wide) infection with Salmonella enterica Typhi. In contrast, infection with the closely related bacterium Salmonella enterica Thyphimurium is usually limited to the gut and causes ...

To mend young girl's heart, Texas doctors tried something new

January 3, 2017
The first hint came in a grainy black and white ultrasound in a doctor's office in West Texas.

Recommended for you

Researchers find way to convert bad body fat into good fat

September 19, 2017
There's good fat and bad fat in our bodies. The good fat helps burn calories, while the bad fat hoards calories, contributing to weight gain and obesity. Now, new research at Washington University School of Medicine in St. ...

New model may help science overcome the brain's fortress-like barrier

September 19, 2017
Scientists have helped provide a way to better understand how to enable drugs to enter the brain and how cancer cells make it past the blood brain barrier.

Cell-based therapy success could be boosted by new antioxidant

September 19, 2017
Cell therapies being developed to treat a range of conditions could be improved by a chemical compound that aids their survival, research suggests.

Study suggests epilepsy drug can be used to treat form of dwarfism

September 19, 2017
A drug used to treat conditions such as epilepsy has been shown in lab tests at The University of Manchester to significantly improve bone growth impaired by a form of dwarfism.

Research predicts how patients are likely to respond to DNA drugs

September 19, 2017
Research carried out by academics at Northumbria University, Newcastle could lead to improvements in treating patients with diseases caused by mutations in genes, such as cancer, cystic fibrosis and potentially up to 6,000 ...

Urine output to disease: Study sheds light on the importance of hormone quality control

September 18, 2017
The discovery of a puddle of mouse urine seems like a strange scientific "eureka" moment.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.