DARPA updateDARPA seeking to improve bio-threat detectors

Infectious microorganisms are on the rise, and the Pentagon is in a rush to develop better detection, treatment, and even all-out prevention. With a need for quick response, it is no surprise that DARPA, the military’s mad-science division, is playing a major role in combating bioterror attacks and natural threats like H1N1.

Katie Drumm writes that now the agency is requesting proposals for a device that would enable faster, more accurate detection of a broad range of biological agents. The Antibody Technology Program hopes to create a biosensor that would identify viral and bacterial threats, and do so using a natural first-line of defense: human antibodies.

This is not the first time DARPA’s asked for better, more versatile microorganism detectors. In 2002 the agency launched the Biosensors Technology Program to figure out the fastest, most effective way to detect a wide array of bio-agents with a single device. Among the contenders were mass spectrometry, a technique to separate and identify molecules based on mass, and hand-held nucleic acid sensors, which would analyze the DNA and RNA of potentially dangerous substances. According to DARPA’s new solicitation, antibody biosensors offered the most reliable detection, across the broadest range of bio-agents. Now they want to make the sensors even better.

Drumm writes that DARPA is asking for proposals that would address the two downsides of antibody-based biosensors. Antibody proteins are fragile, so they are unable to withstand extreme temperatures or survive longer than a few weeks in storage. This is not practical for civilian medical centers, let alone a war-zone. DARPA wants the new biosensors to be as resilient as possible. They are asking for molecular manipulation of the antibodies, so that the biosensors will be stable for five years, and work at temperatures that range from 25 to 70 degrees Celsius (77 to a sweltering 158 degrees Fahrenheit).

Antibodies are produced by the body in reaction to a foreign viral or bacterial threat, called an antigen. A particular antibody can only bind to a single antigen, but science has already created antibodies that can bind to several different ones. Now, DARPA wants them to have even an more diverse “affinity level”: the ability to bind to a potentially endless array of viral or bacterial antigens. The tip of an antibody is extremely variable, which is why different antibodies attach to different antigens. It is this binding that is used by biosensors to identify various microorganisms, and distinguish between them. DARPA wants to control, or “fine-tune” antibody affinity, so that one “master antibody” can bind with millions of antigens.

DARPA’s request is not specific about how they expect the master antibody, and its accompanying biosensor, to be created. Artificial antibodies have been in the making for years, offer a cheaper, more easily manipulated platform, and are becoming more reliable thanks to new technology. Also, researchers at Portland State University have already manufactured a hand-held antibody biosensor, so chances are good that the detection of biothreats will look cooler than a throat swab, too.