In addition to cleaning biological and radiological toxins from blood, the technology shows promise for delivering therapeutic drugs to targeted cells and organs. The technology uses components approved by the U.S. Food and Drug Administration and a novel approach to magnetic filtration.
"The best that doctors can do for most biohazard exposure is supportive treatment," said Michael Kaminski of Argonne's Chemical Engineering Division. "This new system will be designed to directly remove the toxic agents from the bloodstream – quickly and efficiently."
According to Kaminski, the key to the technology is biodegradable nanospheres 100 to 5,000 nanometers in diameter, which are small enough to pass through tiny blood vessels, yet large enough to avoid being filtered from the bloodstream by the kidneys. One nanometer is one millionth of a meter, about 70,000 times smaller than the diameter of an average human hair.
The particles contain a magnetic iron compound and are coated with a type of polyethylene glycol that prevents white blood cells from attacking them.
Attached to the particles' surfaces are proteins that bind to specific toxic agents. Intravenously injected into the patient, the nanospheres circulate through the bloodstream, where their surface proteins bind to the targeted toxins.
"Once the nanospheres have done their work," said Axel J. Rosengart of the University of Chicago Hospitals. "they are removed from the bloodstream by a small dual-channel shunt, similar to exchange transfusion tubing, inserted into an arm or leg artery."
The shunt circulates the blood through an external magnetic separator, where strong magnets immobilize the iron-based particles. Clean blood flows out of the separator and back into the bloodstream.