Over the last five years, optical technologies have gained attention in biodefense and antibiotic resistance applications. Because optical methods allow direct visualization of specific targets and provide a range of quantitative details, they're ideal for tracking pathogens. "These technologies provide very rich information" compared to other approaches, says Qingshan Wei, a researcher at North Carolina State University. "The combination of optical technologies and molecular tools that detect specific targets provides great value."
Two such systems are showing promise for clinical application. The U.S. Biomedical Advanced Research and Development Authority (BARDA) recently approved a $10.7 million contract extension for First Light Diagnostics (Chelmsford, MA) to develop its MultiPath Platform, which detects pathogens and biomarkers in 25 minutes and determines antibiotic susceptibility in 4 hours. The system's optical imaging platform has four fluorescent color channels that detect up to 64 targets and 15 antibiotics in a 16-well cartridge. The system captures an image from each well and color channel, and then counts and analyzes the target cells or molecules. In the case of anthrax, the platform detects infection in less than 30 minutes using a fingerstick blood sample.
To rapidly detect pathogens in the lungs, Proteus Interdisciplinary Research Collaboration (Proteus IRC), based in Edinburgh, Scotland, is developing optical technology to visualize bacteria and the inflammation it creates. In just 60 seconds, bacteria-specific fluorescent probes and fiber-based imaging help clinicians determine which antibiotic therapies to prescribe. Calling the technology a potential game-changer, CARB-X, the world's largest public-private partnership focused on antibacterial preclinical R&D, anticipates application in intensive care settings. The Proteus project received a $1.12 million grant to accelerate development from CARB-X, which is funded by BARDA, Wellcome Trust, the National Institute of Allergy and Infectious Diseases, the British government, and the Gates Foundation.
For threat detection in remote settings, consumer devices as smartphones can be quickly converted into sensitive, single-molecule detectors by adding optical sensors. But reliable field use requires overcoming several hurdles. NC State's Wei notes that laboratory results are often hard to replicate because of the complexity found in real-world situations. Creating portable systems sometimes means sacrificing resolution, particularly when low-cost light sources or battery power sources are used. Field systems also require more validation. "We need to make sure the systems are robust in different environments and will respond to a range of operator skill levels," he says.
Down the road, Wei predicts, plants bioengineered to emit a molecule in response to a biological threat can become active biodefense sensors. "The research direction is changing," says Wei. "But chemistry is the foundation for moving light technology forward."