Innovative Biosensors’ system, marketed under the name BioFlash, is intended for use as a first alert. Identifying agents using other methods, such as polymerase chain reaction (PCR), takes about an hour, including sample preparation time. PCR, which can identify particular stretches of genetic material, can give more information about viruses and bacteria than BioFlash can.
B cells are able to identify threats including bacteria and viruses because of the antibodies on their surfaces. Other detection technologies also use antibodies, says Paul Schaudies, president and CEO of GenArraytion, another company in Rockville, MD, developing pathogen-identification technologies. What’s unique about Todd Rider’s technology, Schaudies says, is that it also takes advantage of cells’ rapid response to identified pathogens.
When the antibodies on the surface of a B cell bind to their target, they initiate a cascade of self-amplifying chemical signals inside the cell. One result is an influx of calcium ions. Rider found a way to take advantage of this. He genetically engineered mouse B cells to make a calcium-sensitive fluorescent enzyme derived from jellyfish. When activated by calcium in the cell, this enzyme, called aequorin, reacts with another jellyfish compound called coelenterazine. One of the products of this reaction is blue light. (The Lincoln Lab researchers have yet to create B cells that can make their own coelenterazine, so the cells must be “loaded” with it.)
Engineered B cells dwelling in the discs have a six-week refrigerated shelf life. They can survive for a week at room temperature. Rider says a system that uses living cells rather than just proteins and other chemical reagents is advantageous, not only because the cells are sensitive and quick to respond to agents, but also because “they grow like weeds.” Unlike detecting reagents based on proteins alone–antibodies, for instance–cell-based detectors replenish themselves.
Innovative Biosensors cannot disclose to whom it has sold the pathogen detectors. However, Richard Thomas, president of its environmental group, notes that the company has a contract with the U.S. Department of Defense for building security in the Washington, DC, area.
Even as the first product based on their technology hits the market, the Lincoln Lab researchers are continuing to develop the system for other applications. One project, says Rider, is to engineer cells that can survive longer in the field without refrigeration. Rider’s group has demonstrated detection of many pathogens and toxins in samples taken from the air, from water, and from nasal swabs, and it is exploring the application of its technology for medical diagnosis.