When a patient succumbs to an infection, it’s not the mere presence of the pathogen that kills them, but rather the sheer quantity of it. With many deadly diseases, the immune system simply can’t keep up. So bioengineers figured that outsourcing some of those duties could help keep patients alive.
A team of bioengineers led by Donald Ingber at Harvard’s Wyss Institute devised a device to filter pathogens from a patient’s blood. Inspired by the spleen, an organ which filters antibody-coated pathogens from the bloodstream, the “biospleen” works by first injecting specially treated, magnetic nanoparticles into the blood flowing through it. The nanoparticles have a protein attached to their surfaces which adheres to bacteria, viruses, and fungi; the protein-coated nanoparticles work like antibodies, which glom onto foreign objects. The biospleen then uses a magnet to pull out the nanoparticles and the pathogens they’re attached to.
The biospleen is similar in concept to dialysis, which mimics the function of the kidneys, but works on pathogens instead of typical bodily waste.
Sara Reardon, reporting for Nature News, has more details:
To test the device, Ingber and his team infected rats with either E. coli orStaphylococcus aureus and filtered blood from some of the animals through the biospleen. Five hours after infection, 89% of the rats whose blood had been filtered were still alive, compared with only 14% of those that were infected but not treated. The researchers found that the device had removed more than 90% of the bacteria from the rats’ blood. 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.
Ingber and his team also tested the device using human volumes of blood, and they found that it took about five hours to filter most pathogens from five liters of blood.
If the device makes it into trials, which could happen in just a few years, it could give doctors the upper hand in a number of intractable infections, including HIV and Ebola. The biospleen could reduce the pathogen load in a patient’s blood, leaving the drugs that normally treat the infection to clear the virus or bacteria from the patient’s organs. In acute infections, like Ebola, it would also buy doctors valuable time in their efforts to eliminate the virus before the patient succumbs.