The system is portable and would need minimal training to operate, according to a proof-of-concept study published in the journal PLoS ONE.
Once blood has been donated, it is usually separated into three parts: red blood cells, plasma and platelets. This way, one donation can be used to help separate patients, who may each need just one part of the blood.
It is routine to do this using a centrifuge, an expensive system which requires electricity and is normally housed in a centralised health centre. This means the process is often far less efficient in poorer regions that may lack a centrifuge or depend on off-grid clinics.
Around 1 billion people in the global South are dependent on health systems with no electricity. Power outages in the wake of natural disasters can also render any available centrifuges unusable.
A passive filtration system to separate blood without expensive infrastructure is being developed at the University of Houston in the United States. It works by applying compression to a slightly tilted blood bag, using metal plates and an air-spring. This speeds up the natural separation of red blood cells from platelet-rich plasma.
We definitely think this approach could have particular usefulness in the developing world, as buying even a single centrifuge would be prohibitively expensive for many areas
The plasma then flows to the top of the bag, before it gets released through a valve into a device which houses thousands of microscopic filters. These filters separate it into purified plasma and concentrated platelet solution, based on particle size.
The whole system costs around US$200 to produce.
“We definitely think this approach could have particular usefulness in the developing world, as buying even a single centrifuge would be prohibitively expensive for many areas,” says research team leader Sergey Shevkoplyas in an email interview with SciDev.Net.
This technology has potential, says Jose Cancelas, professor of paediatrics and deputy director of Hoxworth Blood Center at the University of Cincinnati, who is not involved in the study. But the reliable, safe development of a blood transfusion programme still requires electricity.
“This technology does not address the need of energy-dependent preservation systems such as cold storage, to maintain the integrity of these blood products,” explains Cancelas. Osaro Erhabor, a professor of haematology at Usmanu Danfodio University in Sokoto, Nigeria, says whole blood transfusion is “a waste of scarce human resource” in developing countries, so tech that separates blood into components is particularly useful.
"This system could become a cost effective and adaptable alternative," adds Erhabor.
The developers believe that if brought to market, the device could boost healthcare in even the most remote rural areas. “There are, of course, also a variety of regulatory hurdles that would have to be overcome before we can market this system,” says Sean Gifford, President of Halcyon Biomedical, who designed the filter device along with Shevkoplyas.