Although several studies are currently exploring the use of man-made nanoparticles for delivering medication to targeted areas of the body, care must be taken to ensure that those particles don't cause adverse reactions when introduced to the bloodstream. Scientists at the MIT-affiliated Whitehead Institute, however, are taking a different approach to the same basic concept. They've developed a method of attaching chemical payloads to red blood cells.

Besides their being unlikely to get attacked by the immune system or cause toxic reactions, red blood cells (RBCs) are also a good choice due to the facts that they're the most abundant type of cell in the human body, and they can live for up to 120 days in circulation. Additionally, because RBCs lose their genetic material upon maturation, their introduction isn't likely to cause problems such as tumor formation.

Led by professors Harvey Lodish and Hidde Ploegh, the researchers started by genetically manipulating early-stage RBC progenitor cells, to produce proteins on their outer surface. As those cells matured into proper RBCs and lost their genetic material, the proteins nonetheless stayed intact.

In a process known as "sortagging," the scientists then used the bacterial enzyme sortase A to create a bond between those proteins and a substance of their choice – that substance could include any number of medications, or antibodies that could bind with toxins present in the body.

It is hoped that once developed further, the technique could be used for things like removing harmful cholesterol from the bloodstream, carrying clot-busting proteins to blocked blood vessels, delivering anti-inflammatory antibodies to sites of inflammation, or to suppress unwanted immune responses to protein-based therapies.

DARPA (the Defense Advanced Research Projects Agency) is funding the project, as it may also have applications in the development of treatments or vaccines for biological weapons.