(Press-News.org) WEST LAFAYETTE, Ind. – Researchers have created a new type of biosensor that can detect minute concentrations of glucose in saliva, tears and urine and might be manufactured at low cost because it does not require many processing steps to produce.
"It's an inherently non-invasive way to estimate glucose content in the body," said Jonathan Claussen, a former Purdue doctoral student and now a research scientist at the U.S. Naval Research Laboratory. "Because it can detect glucose in the saliva and tears, it's a platform that might eventually help to eliminate or reduce the frequency of using pinpricks for diabetes testing. We are proving its functionality."
Claussen and Purdue doctoral student Anurag Kumar led the project, working with Timothy Fisher, a Purdue professor of mechanical engineering, D. Marshall Porterfield, a professor of agricultural and biological engineering, and other researchers at the university's Birck Nanotechnology Center.
Findings are detailed in a research paper appearing online this week in the journal Advanced Functional Materials.
"Most sensors typically measure glucose in blood," Claussen said. "Many in the literature aren't able to detect glucose in tears and the saliva. What's unique is that we can sense in all four different human serums: the saliva, blood, tears and urine. And that hasn't been shown before."
The paper, featured on the journal's cover, was written by Claussen, Kumar, Fisher, Porterfield, and Purdue researchers David B. Jaroch, M. Haseeb Khawaja, and Allison B. Hibbard.
The sensor has three main parts: layers of nanosheets resembling tiny rose petals made of a material called graphene, which is a single-atom-thick film of carbon; platinum nanoparticles; and the enzyme glucose oxidase.
Each petal contains a few layers of graphene stacked on each other. The edges of the petals have dangling, incomplete chemical bonds, defects where the platinum nanoparticles can attach. Electrodes are formed by combining the nanosheet petals and platinum nanoparticles. Then the glucose oxidase attaches to the platinum nanoparticles. The enzyme converts glucose to peroxide, which generates a signal on the electrode.
"Typically, when you want to make a nanostructured biosensor you have to use a lot of processing steps before you reach the final biosensor product," Kumar said. "That involves lithography, chemical processing, etching and other steps. The good thing about these petals is that they can be grown on just about any surface, and we don't need to use any of these steps, so it could be ideal for commercialization."
In addition to diabetes testing, the technology might be used for sensing a variety of chemical compounds to test for other medical conditions.
"Because we used the enzyme glucose oxidase in this work, it's geared for diabetes," Claussen said. "But we could just swap out that enzyme with, for example, glutemate oxidase, to measure the neurotransmitter glutamate to test for Parkinson's and Alzheimer's, or ethanol oxidase to monitor alcohol levels for a breathalyzer. It's very versatile, fast and portable."
The technology is able to detect glucose in concentrations as low as 0.3 micromolar, far more sensitive than other electrochemical biosensors based on graphene or graphite, carbon nanotubes and metallic nanoparticles, Claussen said
"These are the first findings to report such a low sensing limit and at the same time such a wide sensing range," he said.
The sensor is able to distinguish between glucose and signals from other compounds that often cause interference in sensors: uric acid, ascorbic acid and acetaminophen, which are commonly found in the blood. Unlike glucose, those compounds are said to be electroactive, which means they generate an electrical signal without the presence of an enzyme.
Glucose by itself doesn't generate a signal but must first react with the enzyme glucose oxidase. Glucose oxidase is used in commercial diabetes test strips for conventional diabetes meters that measure glucose with a finger pinprick.
INFORMATION:
The research has been based at Purdue's Birck Nanotechnology Center at the university's Discovery Park. The research has been funded by the U.S. Office of Naval Research and the National Science Foundation.
Writer: Emil Venere, 765-494-4709, venere@purdue.edu
Sources: Jonathan Claussen, 202-767-3560, jonathan.claussen@gmail.com
Anurag Kumar, kumar.anuragsharma@gmail.com
Timothy Fisher, 765-494-5627, tsfisher@purdue.edu
D. Marshall Porterfield, 765-494-1190, porterf@purdue.edu
Related websites:
Timothy Fisher: https://engineering.purdue.edu/ME/People/ptProfile?id=28558
IMAGE CAPTION:
These color-enhanced scanning electron microscope images show nanosheets resembling tiny rose petals. The nanosheets are key components of a new type of biosensor that can detect minute concentrations of glucose in saliva, tears and urine. The technology might eventually help to eliminate or reduce the frequency of using pinpricks for diabetes testing. (Jeff Goecker, Purdue University)
A publication-quality image is available at http://news.uns.purdue.edu/images/2012/fisher-sensor.jpg
ABSTRACT
Nanostructuring Platinum Nanoparticles on Multilayered Graphene Petal Nanosheets for Electrochemical Biosensing
Jonathan C. Claussen2, Anurag Kumar1,David B. Jaroch3, M. Haseeb Khawaja1, Allison B. Hibbard1, D. Marshall Porterfield,2, 3, and Timothy S. Fisher1
1 Birck Nanotechnology Center, School of Mechanical Engineering, Purdue University
2Birck Nanotechnology Center, Department of Agricultural and Biological Engineering, Purdue University School of Mechanical Engineering
3Birck Nanotechnology Center, Weldon School of Biomedical Engineering, Purdue University
Hybridization of nanoscale metals and carbon nanotubes into composite nanomaterials has produced some of the best-performing sensors to date. The challenge remains to develop scalable nanofabrication methods that are amenable to the development of sensors with broad sensing ranges. A scalable nanostructured biosensor based on multilayered graphene petal nanosheets (MGPNs), Pt nanoparticles, and a biorecognition element (glucose oxidase) is presented. The combination of zero-dimensional nano-particles on a two-dimensional support that is arrayed in the third dimension creates a sensor platform with exceptional characteristics. The versatility of the biosensor platform is demonstrated by altering biosensor performance (i.e., sensitivity, detection limit, and linear sensing range) through changing the size, density, and morphology of electrodeposited Pt nanoparticles on the MGPNs. This work enables a robust sensor design that demonstrates exceptional performance with enhanced glucose sensitivity (0.3 µM detection limit, 0.01 mM linear sensing range), a long stable shelf-life (> 1 month), and a high selectivity over electroactive, interfering species commonly found in human serum samples.
Sensor detects glucose in saliva and tears for diabetes testing
2012-08-23
[Attachments] See images for this press release:
ELSE PRESS RELEASES FROM THIS DATE:
Field guide to the Epstein-Barr virus charts viral paths toward cancer
2012-08-23
Researchers from The Wistar Institute and Memorial Sloan-Kettering Cancer Center (MSKCC) have teamed to publish the first annotated atlas of the Epstein-Barr virus genome, creating the most comprehensive study of how the viral genome interacts with its human host during a latent infection. Epstein-Barr virus (EBV), which is thought to be responsible for one percent of all human cancers, establishes a latent infection in nearly 100 percent of infected adult humans.
The atlas is designed to guide researchers toward new means of creating therapies against EBV-latent infection ...
For mitochondria, bigger may not be better
2012-08-23
Goldilocks was on to something when she preferred everything "just right." Harvard Medical School researchers have found that when it comes to the length of mitochondria, the power-producing organelles, applying the fairy tale's mantra is crucial to the health of a cell. More specifically, abnormalities in mitochondrial length promote the development of neurodegenerative diseases such as Alzheimer's.
"There had been a fair amount of interest in mitochondria in Alzheimer's and tau-related diseases, but causality was unknown," said Brian DuBoff, first author of the study ...
August 2012 tips from the journals of the American Society for Microbiology
2012-08-23
Boost for Efforts to Prevent Microbial Stowaways on Interplanetary Spacecraft
Efforts to expunge micro-organisms from spacecraft assembly cleanrooms, and the spacecraft themselves, inadvertently select for the organisms that are often the most fit to survive long journeys in space. This has the risk of thwarting the goal of avoiding contaminating other celestial bodies, as well as samples brought back to earth, according to Myron La Duc of the Jet Propulsion Laboratory (JPL), California Institute of Technology, and his collaborators. Their research is published in the ...
Cancer survival in Germany after the fall of the Iron Curtain
2012-08-23
Data from the 1970s and 1980s show that people affected by cancer survived significantly longer in West Germany than cancer patients behind the Iron Curtain. Looking at a diagnosis period from 1984 to 1985 in the former German Democratic Republic, 28 percent of colorectal cancer patients, 46 percent of prostate cancer patients, and 52 percent of breast cancer patients survived the first five years after diagnosis. By contrast, 5-year survival rates for people in West Germany affected by these types of cancer were 44 percent, 68 percent, and 68 percent in the years from ...
NASA sees Tropical Storm Isaac bring heavy rains to Eastern Caribbean
2012-08-23
VIDEO:
An animation of satellite observations from Aug. 20-23, 2012, shows Tropical Storm Isaac moving through the eastern Caribbean Sea. This visualization was created by the NASA GOES Project at NASA's...
Click here for more information.
NASA's Tropical Rainfall Measuring Mission satellite captured rainfall data from Tropical Storm Isaac as it continues moving through the Caribbean Sea.
After a quiet July, the Atlantic has seen a sharp increase in tropical activity. ...
Past tropical climate change linked to ocean circulation, says Texas A&M team
2012-08-23
A new record of past temperature change in the tropical Atlantic Ocean's subsurface provides clues as to why the Earth's climate is so sensitive to ocean circulation patterns, according to climate scientists at Texas A&M University.
Geological oceanographer Matthew Schmidt and two of his graduate students teamed up with Ping Chang, a physical oceanographer and climate modeler, to help uncover an important climate connection between the tropics and the high latitude North Atlantic. Their new findings are in the current issue of PNAS (Proceedings of the National Academy ...
IBC 2012: New standard HEVC encodes films more efficiently
2012-08-23
The opening ceremonies for the Olympic Games captivated countless viewers all over the world in front of their televisions, astounding them with a gigantic show. Relatively few people were able to have a live experience of the spectacle at the London stadium. Still, some of the fans watching the show felt as if they were there live, even though they were only sitting in front of a large cinema screen. That's because a few movie theaters showed the opening ceremonies in 8K-resolution, which corresponds to 33 megapixels.
The resolution on home televisions will soon be enhanced ...
IBC 2012: Mini-camera with maxi-brainpower
2012-08-23
Just a few more meters to the finish line. The mountain biker jumps over the last hill and takes the final curve, with the rest of the competition close at his heels. At such moments, you do not want to just watch, you would really love to put yourself in the same shoes as the athlete. How does he push the pace on the final stretch? How fast is his pulse racing? What does he feel like? Viewers will soon be able to obtain this information in real time, directly with the images. Because the INCA intelligent camera, engineered by Fraunhofer researchers in Erlangen, makes completely ...
AGU: Link found between cold European winters and solar activity
2012-08-23
WASHINGTON – Scientists have long suspected that the Sun's 11-year cycle influences climate of certain regions on Earth. Yet records of average, seasonal temperatures do not date back far enough to confirm any patterns. Now, armed with a unique proxy, an international team of researchers show that unusually cold winters in Central Europe are related to low solar activity – when sunspot numbers are minimal. The freezing of Germany's largest river, the Rhine, is the key.
Although the Earth's surface overall continues to warm, the new analysis has revealed a correlation ...
Advantage flu virus
2012-08-23
When you are hit with the flu, you know it immediately -- fever, chills, sore throat, aching muscles, fatigue. This is your body mounting an immune response to the invading virus. But less is known about what is happening on the molecular level.
Now Northwestern University scientists have discovered one of the ways the influenza virus disarms our natural defense system. The virus decreases the production of key immune system-regulating proteins in human cells that help fight the invader. The virus does this by turning on the microRNAs -- little snippets of RNA -- that ...