Sticky nanobeads can clear bacteria, viruses from blood

Magnetic beads trap a bacterium (blue) and allow a new device to filter it from the blood.
Magnetic beads trap a bacterium (blue) and allow a new device to filter it from the blood.

Bioengineers at Harvard’s Wyss Institute have developed a blood filter that grabs toxins from the bloodstream using protein-coated nanobeads and magnets. In early tests, the biomechanical treatment removed more than 90 per cent of toxins from infected human blood within a few hours.

When our immune system fights an infection, the dying virus releases toxins into the bloodstream that can cause sepsis. Doctors can’t always pinpoint the specific pathogen that causes sepsis, so they use antibiotics to flood the bloodstream, a strategy that can lead to drug-resistance.

The “artificial spleen” instead mechanically clears pathogens from the bloodstream, thereby reducing reliance on heavy antibiotic doses. Its magnetic nanobeads are coated with a modified human protein that binds to sugar molecules on the surfaces of more than 90 different bacteria, viruses and fungi, as well as to toxins released by dead bacteria. When those nanobeads are mixed with infected blood they adhere to pathogens, and then, as the blood passes through channels inside the device, magnets pull out the beads with pathogens attached. Clean blood is routed back into the patient.

The blood filter could play a role in treating HIV and Ebola by lowering the level of the virus in the blood to manageable levels. It could also help scientists harvest viruses from blood to study better ways to treat them.

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