Our spleens filter out toxins from our blood and help us fight infections. But serious infections can overpower our bodies' ability to fight them off, especially among older adults whose immune systems are weaker. Now, a research team led by Donald Ingber, MD, PhD, of Harvard has come up with an artificial "biospleen" that can trap bacteria, fungi and viruses and remove them from circulating blood. Science Magazine describes the device in a news story:
The team first needed a way to capture nasties. They coated tiny magnetic beads with fragments of a protein called mannose-binding lectin (MBL). In our bodies, MBL helps fight pathogens by latching onto them. Ingber and colleagues showed that the sticky beads could grab a variety of microbes in the test tube.
With that key challenge out of the way, the researchers were ready to design the rest of the system. They engineered a microchiplike device a little bigger than a deck of cards that works somewhat like a dialysis machine. As blood enters the device, it receives a dose of the magnetic beads, which snatch up bacteria, and then fans out into 16 channels. As the blood flows across the device, a magnet pulls the beads--and any microbes or toxins stuck to them--out of the blood, depositing them in nearby channels containing saline.
The researchers first tested their device with donated human blood tainted with bacteria. They found that filtering the blood through the device five times could eliminate 90% of the microbes.
The device improved survival rates in rats and may decrease the incidence of sepsis, a dangerous side effect of severe infections. The researchers also found that the device could filter the total volume of blood in an adult human - about 5 liters or (1.3 gallons) - in about five hours.
Previously: Our aging immune systems are still in business, but increasingly thrown out of balance
Image, of the magnetic MBL-coated nanobeads beads capturing pathogens, from Harvard University Wyss Institute