Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

UGA researchers develop rapid diagnostic test for pathogens, contaminants

20.07.2012
Using nanoscale materials, researchers at the University of Georgia have developed a single-step method to rapidly and accurately detect viruses, bacteria and chemical contaminants.
In a series of studies, the scientists were able to detect compounds such as lactic acid and the protein albumin in highly diluted samples and in mixtures that included dyes and other chemicals. Their results suggest that the same system could be used to detect pathogens and contaminants in biological mixtures such as food, blood, saliva and urine.

"The results are unambiguous and quickly give you a high degree of specificity," said senior author Yiping Zhao, professor of physics in the UGA Franklin College of Arts and Sciences and director of the university's Nanoscale Science and Engineering Center.

Zhao and his co-authors—doctoral students Jing Chen and Justin Abell and professor Yao-wen Huang of the UGA College of Agricultural and Environmental Sciences—used nanotechnology to combine two well-known techniques and create their new diagnostic test. Their results appear in the early online edition of the journal Lab on a Chip and were recently presented at the SPIE Defense, Security and Sensing conference.

The first component of their two-in-one system uses a technique known as surface enhanced Raman spectroscopy, or SERS, which measures the change in frequency of a laser as it scatters off a compound. Every compound displays a series of distinctive changes in frequency, or Raman shifts, that are as unique as a fingerprint. The signal produced by Raman scattering is inherently weak, but Zhao and his colleagues have arrayed silver nanorods 1,000 times finer than the width of a human hair at a precise angle to significantly amplify the signal. In previous studies with Ralph Tripp in the UGA College of Veterinary Medicine and chemist Richard Dluhy in the Franklin College, they demonstrated that the use of SERS with silver nanorods could identify viruses such as HIV and RSV isolated from infected cells.

"In a clinical setting, the sample that you obtain from patients typically contains bacteria or viruses as well as a lot of fluid—as in blood, urine or saliva—that contains biological agents that interfere with the signal you're trying to detect," Zhao said. "To develop a diagnostic that could be used at the point of care, we needed a way to separate those agents."

Once again, the scientists turned to nanotechnology to create a next-generation diagnostic test. Using traditional thin layer chromatography, or TLC, scientists blot a drop of sample onto a porous surface. They then apply a solvent such as methanol to the sample, and the sample components separate based on how strongly they're attracted to the solvent and the surface.

Study co-author Justin Abell, a doctoral student in the UGA College of Engineering, explained that TLC typically requires a large sample volume because the compound of interest soaks into the surface in addition to moving along it, like a stain on a rug. The silver nanorod surface that the researchers use, in contrast, allows them to use a miniscule amount of sample in a technique known as ultra-thin layer chromatography.

"In our case, the nanorods are acting as the detection medium but also as the separation medium," Abell said, "so it's a two-in-one system."

To test their method, the researchers used mixtures of dyes, the organic chemical melamine, lactic acid and the protein albumin. In each case, they were able to directly identify the compounds of interest, even in samples diluted to concentrations below 182 nanograms per milliliter-roughly 200 billionths of a gram in a fifth of a teaspoon. And while the detection of viruses using techniques such as polymerase chain reaction can take days or even weeks and requires fluorescent labels, the on-chip method developed by the UGA researchers yields results in less than an hour without the use of molecular labels.

The researchers are currently testing their technique with biological samples from Tripp's lab that contain viruses, and Zhao said preliminary results are promising. He adds that while his team is focused on health and food safety applications, SERS and ultra-thin layer chromatography can be used to detect compounds of all types—everything from forensic materials at a crime scene to environmental pollutants. His team also is working with colleagues across campus to create an online encyclopedia that would allow technicians to identify viruses, bacteria, biomarkers and pharmaceuticals based on their distinctive Raman shifts.

"Every compound has a unique SERS spectrum," Zhao said, "so this is a very robust technology whose applications are practically endless."

The research was supported by the U.S. Department of Agriculture, the National Science Foundation and the UGA College of Agricultural and Environmental Sciences.

Yiping Zhao | EurekAlert!
Further information:
http://www.uga.edu

More articles from Health and Medicine:

nachricht Satellites, airport visibility readings shed light on troops' exposure to air pollution
09.12.2016 | Veterans Affairs Research Communications

nachricht Oxygen can wake up dormant bacteria for antibiotic attacks
08.12.2016 | Penn State

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>