During times of stress, the human body often has a difficult time fighting infections or other nasty health issues. That subtle weakness may soon change with a new high-tech gadget which can clear infections and even unknown pathogens from blood.
Because blood infections are difficult to treat and can lead to extreme immune responses in the body, many drugs and medications aimed at clearing them come with side-effects. Inspired by the human spleen, an artificial version can be used instead to rid the blood of these foreign invaders and reduce the use of large-scale antibiotics. The use of these medications can also lead to antibiotic resistance when used too often.
Acting as a filter, the "biospleen" is currently being developed by a team of researchers led by Donald Ingber from Harvard University’s Wyss Institute for Biologically Inspired Engineering in Boston. It uses a special magnetic nanobead filter which are coated in a protein called mannose-binding lectin or "MBL". This protein is also common in humans and combines with sugar molecules of over 90 different bacteria, viruses, and even fungi.
By utilizing the artificial spleen, researchers can also help prevent sepsis which is caused by the release of dead bacteria, often due to the use of medications which act to kill the bacteria instead of filtering it.
Like a Magnet
As infected blood passes through the filter, MBL-coated nanobeads bind to most of the pathogens and become attracted to a magnet within the artificial spleen. This process combines them to remove them completely out of the blood, leaving it purified and ready to be pumped right back into the patient.
As a patient’s blood passes through the biospleen, these MBL-coated magnetic nanobeads bind to the majority of pathogens. A magnet in the artificial spleen then pulls the beads and the bacteria and viruses they’re attached to out of the blood, leaving the blood purified and ready to be pumped back into the patient.
The device has now been tested on rats infected with either E. coli or Staphylococcus aureus. Five hours after infection, 89% of the rats whose blood had been filtered through the biospleen were still alive, compared to only 14% of those who were not treated. Impressively, the scientists found that the device had removed more than 90% of the bacteria from the rats’ blood. The results are published in Nature Medicine.
“The rats whose blood had been filtered also had less inflammation in their lungs and other organs, suggesting they would be less prone to sepsis,” writes Reardon.
The team then tested the biospleen on five litres of blood, which is the volume in the average human, and found that within five hours, the device could remove most pathogens.
Reardon explains at Nature News: “That degree of efficacy is probably enough to control an infection, Ingber says. Once the biospleen has removed most pathogens from the blood, antibiotics and the immune system can fight off remaining traces of infection — such as pathogens lodged in the organs, he says.”
The biospleen could also be used to treat viral infections such as HIV and Ebola, according to Ingber, and testing as now begun in pigs.
Nigel Klein, an infection and immunity expert at University College London in the UK, told Reardon that he expects the biospleen could be trialed in humans within a couple of years.