Featured Research

from universities, journals, and other organizations

Rapid diagnostic test for pathogens, contaminants

Date:
July 19, 2012
Source:
University of Georgia
Summary:
Using nanoscale materials, researchers have developed a single-step method to rapidly and accurately detect viruses, bacteria and chemical contaminants. The scientists were able to detect compounds such as lactic acid and albumin in highly diluted samples and in mixtures that included dyes and other chemicals. Their results suggest the same system could be used to detect pathogens and contaminants in biological mixtures such as food, blood, saliva and urine.

Nanotechnology - rapid diagnostic test - Huang, Chen, Zhao, Abell-h.group University of Georgia researchers, left to right, Yao-Wen Huang, Jing Chen, Yiping Zhao and Justin Abell stand in front of an electron beam evaporator at the UGA Nanoscale Science and Engineering Center. The instrument, designed and created by the UGA Instrument Shop, is used to deposit silver nanorods 1,000 times finer than the width of a human hair on a chip that can be used to detect viruses, bacteria and chemical contaminants.
Credit: Image courtesy of University of Georgia

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.


Story Source:

The above story is based on materials provided by University of Georgia. The original article was written by Sam Fahmy. Note: Materials may be edited for content and length.


Journal Reference:

  1. Jing Chen, Justin Abell, Yao-wen Huang, Yiping Zhao. On-Chip Ultra-Thin Layer Chromatography and Surface Enhanced Raman Spectroscopy. Lab on a Chip, 2012; DOI: 10.1039/C2LC40221A

Cite This Page:

University of Georgia. "Rapid diagnostic test for pathogens, contaminants." ScienceDaily. ScienceDaily, 19 July 2012. <www.sciencedaily.com/releases/2012/07/120719132951.htm>.
University of Georgia. (2012, July 19). Rapid diagnostic test for pathogens, contaminants. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2012/07/120719132951.htm
University of Georgia. "Rapid diagnostic test for pathogens, contaminants." ScienceDaily. www.sciencedaily.com/releases/2012/07/120719132951.htm (accessed July 25, 2014).

Share This




More Matter & Energy News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

TSA Administrator on Politics and Flight Bans

TSA Administrator on Politics and Flight Bans

AP (July 24, 2014) TSA administrator, John Pistole's took part in the Aspen Security Forum 2014, where he answered questions on lifting of the ban on flights into Israel's Tel Aviv airport and whether politics played a role in lifting the ban. (July 24) Video provided by AP
Powered by NewsLook.com
Creative Makeovers for Ugly Cellphone Towers

Creative Makeovers for Ugly Cellphone Towers

AP (July 24, 2014) Mobile phone companies and communities across the country are going to new lengths to disguise those unsightly cellphone towers. From a church bell tower to a flagpole, even a pencil, some towers are trying to make a point. (July 24) Video provided by AP
Powered by NewsLook.com
Algonquin Power Goes Activist on Its Target Gas Natural

Algonquin Power Goes Activist on Its Target Gas Natural

TheStreet (July 23, 2014) When The Deal's Amanda Levin exclusively reported that Gas Natural had been talking to potential suitors, the Ohio company responded with a flat denial, claiming its board had not talked to anyone about a possible sale. Lo and behold, Canadian utility Algonquin Power and Utilities not only had approached the company, but it did it three times. Its last offer was for $13 per share as Gas Natural's was trading at a 60-day moving average of about $12.50 per share. Now Algonquin, which has a 4.9% stake in Gas Natural, has taken its case to shareholders, calling on them to back its proposals or, possibly, a change in the target's board. Video provided by TheStreet
Powered by NewsLook.com
Robot Parking Valet Creates Stress-Free Travel

Robot Parking Valet Creates Stress-Free Travel

AP (July 23, 2014) 'Ray' the robotic parking valet at Dusseldorf Airport in Germany lets travelers to avoid the hassle of finding a parking spot before heading to the check-in desk. (July 23) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

    Health News

      Environment News

        Technology News



          Save/Print:
          Share:

          Free Subscriptions


          Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

          Get Social & Mobile


          Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

          Have Feedback?


          Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
          Mobile: iPhone Android Web
          Follow: Facebook Twitter Google+
          Subscribe: RSS Feeds Email Newsletters
          Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins