We all appreciate the power of small. The iPod Nano is tiny, lightweight and puts an enormous library of music all in one place. In the worlds of technology and music, this tiny device is huge.
But when nanotechology — in which things are much, much smaller, at the scale of one-billionth of a meter — is applied to disease and illness, the strides are even bigger, because lives are at stake.
Three University of Georgia professors are putting nanotechnology to work as a tool for diagnosis.
Veterinary medicine professor Ralph Tripp, physics professor Yiping Zhao and chemistry professor Rich Dluhy have developed slides lined with tiny silver particles that can help identify viruses and bacteria that come in contact with them. The slides can be loaded onto a handheld device, called the FirstDefender, which gives a diagnosis within seconds.
Although not yet as small as an iPod Nano, the device puts a large library of pathogens — from influenza to E. coli — at the user’s fingertips. Specimens can be placed on a slide that fits the FirstDefender, like a testing strip in a glucometer. The device then rapidly delivers a readout.
“Obviously there are many pathogens. Most of those we’re working on are emerging infectious diseases,” said Tripp. “Prioritizing what goes into that library is based on human need.”
Tripp and his fellow researchers have big plans for this small device.
‘Fingerprints’ of disease
The FirstDefender was originally developed by Ahura Scientific after the 2001 anthrax attacks, in which deadly spores were sent through the mails, eventually killing several people who were exposed to them. The device was intended to help first responders easily and rapidly distinguish the lethal white powder from similar-looking but harmless substances such as baby powder – without sending samples to a lab.
Laboratory analysis can take hours or even days – not fast enough when lives are at stake.
Tripp, Zhao and Dluhy wanted to create pathogen-detecting technology with greater sensitivity, specificity and speed. Their device uses a technique, known as surface-enhanced Raman scattering, that captures the changes in vibration frequency that occur when the light from a laser is scattered off the DNA or RNA of a bacteria or virus.
When a laser shines on the virus, “the molecular vibrations act as sort of molecular fingerprints,” said Dluhy. “We can analyze those fingerprints for particular characteristics, so we can tell if it’s a particular virus or if there’s a particular genetic mutation in that virus.”
Now, Tripp hopes to prove that diagnoses can be made not just in a matter of minutes, but at the point of care.
To make the case for rapid on-site diagnostics, Tripp is collaborating with Larry Anderson, a professor and pediatrician at Emory University School of Medicine. At Emory, Tripp and Anderson are conducting a clinical study of infants potentially infected with respiratory viruses.
“There are lots of things that can cause upper respiratory tract illnesses, from bacteria to viruses, or an immune reaction [due] to allergies,” said Tripp.
He said being able to see right away whether a person has a simple cold or a more dangerous respiratory virus would allow doctors to manage illnesses better, using appropriate drugs and, if necessary, isolation.
Anderson is collecting samples taken from infants’ mouths and noses to make diagnoses using traditional lab tests. Using the FirstDefender on the same samples, Tripp has seen promising results so far.
Although the study is still in progress, the consistency in diagnoses between the two methods suggests that the the FirstDefender “can rapidly and accurately detect the virus in clinical specimens,” he said. The researchers say the new applications for the device are in the late stages of development.
“Potentially it’s much cheaper [than traditional methods],” said Anderson, “and it could be used in a variety of settings; it doesn’t require such a sophisticated laboratory as before.”
Safety on the table
Beyond infectious diseases, the FirstDefender could also identify foodborne illness, according to Zhao.
Salmonella and E. coli bacteria are the No. 1 and No. 5 bacterial causes of foodborne illness. The Georgia Department of Public Health reports that about 1,500 cases of salmonella and 50 cases of E. coli occur every year in the state. Zhao believes nanotechnology could cut those figures.
“The first thing is to prevent [contamination], to do quality control for the food. The second thing is to know as soon as possible what kind of bacteria caused this disease, and then they can treat it accordingly,” said Zhao.
Current codes on food safety require inspectors to take samples of meat and poultry from processing plants to a USDA regional testing laboratory. The FirstDefender would allow inspection to occur in the food processing plants or even on the farm, stopping bacterial outbreaks before they start.
Zhao also sees applications for the technology in the food service industry. “In the future, maybe you’ll go to a fast-food restaurant and get a burger, which we could test for bacteria right there. If we can do that, then it’d be perfect,” he said.
The availability of a rapid, portable diagnostic device would do more than eliminate the need to send samples from hospitals and doctors’ offices to external laboratories. The technology could also be applied in the field to address threats posed by constantly emerging zoonotic diseases — the kind that can pass between species, as between livestock and humans.
“Zoonotics is where your public health and your agricultural health really overlap,” said S. Mark Tompkins, associate professor of infectious diseases, “so having something that’s point-of-care, with rapid identification of a pathogen in any number of scenarios, would be very useful.”
Of primary concern to Georgians are H1N1 and H5N1— flu strains originating in birds and pigs. Between 2009 and 2010, the Georgia Division of Public Health reported more than 1,000 cases of H1N1, or swine flu, more than 80 of them resulting in death. Epidemiologists fear that an outbreak H5N1, or avian flu, could take a similar toll.
Tripp and his colleagues have had success diagnosing strains of avian and swine flu in laboratory settings using the FirstDefender. They hope field tests for those diagnoses will be as successful as those they’ve already completed for viruses linked to bats outside the United States.
The technology proved effective in detecting hendra, a virus found in bats in Australia, on tarps laid beneath bat-laden trees, said Tripp. The researchers plan to conduct similar research to detect West Nile virus in Georgia, he said.
Real battlefield applications
The technology also has potential applications for the Department of Defense – serving military personnel wounded in combat.
“When they get a wound, it’s easy to treat the wound. However, if they get infected by bacteria, you have to prescribe the right antibiotics to kill the bacteria,” said Zhao. “And most U.S. doctors don’t want to use antibiotics because it can cause the bacteria to be resistant.”
Having diagnostic technology on hand would allow military medical personnel to prescribe the exact drug to kill that bacteria, as opposed to allowing it to become resistant and endanger others.
“At the end of the day, even if we work with animals, we’re trying to better protect human health,” said Tripp. “Early detection is critical, and early detection allows you to take actions that you wouldn’t otherwise be able to take.”
Chelsea Toledo completed her master’s degree in Health and Medical Journalism from the University of Georgia in May 2012. This summer, she is interning as a science writer at the National Institute of General Medical Sciences, a branch of the National Institutes of Health in Bethesda, Md.