NEW DELHI: A drop of tear from your eyes, saliva or urine could soon substitute the drop of blood as the medium for a glucose test.
In a major breakthrough, an IIT-Delhi alumni Anurag Kumar, who is presently pursuing his Ph.D from Purdue University in the US, has 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. 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," the team said.
The joint team of researchers from Purdue and US Naval Research Laboratory published their findings this week in the journal, Advanced Functional Materials.
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.
Speaking to TOI from the US, Kumar said, "Most sensors typically measure glucose in blood. 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."
He added, "It is a graphene based sensor that has very low detection limit for glucose and a very wide sensing range. A human tear could contain 0.2 to 0.4 milimose glucose. Our sensor can detect 0.01 to 50 milimose of glucose. Soon, we can tell whether a patient is diabetic or not just by testing his urine, saliva or tear instead of a finger prick for blood."
Kumar, who hails from Talaiya, a small town in Jharkhand, is working towards commercializing the technology "just by changing the enzyme, we can use the same nanostructure materiel to measure concentration level of other chemicals like the one that predicts Parkinson's and Alzheimer's."
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 stacked graphene. The edges of the petals have dangling, incomplete chemical bonds, defects where 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," he added.
"Because we used the enzyme glucose oxidase in this work, it's geared for diabetes," said Jonathan Claussen, a research scientist at the US Naval Research Laboratory. "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," he explained.
These are the first findings to report such a low sensing limit and, at the same time, such a wide sensing range. 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 electro-active, 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 blood sugar level with a finger pinprick.
Breakthrough to help paralyzed regain speech
PTI | Aug 24, 2012, 05.17AM IST
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WASHINGTON: Paralysis sufferers could soon learn to talk again after scientists discovered how the brain allows humans to pronounce vowels, a new study has claimed. Scientists are investigating the use of brain waves to create a new form of communication which could return the power of speech to paralysis sufferers like Physicist Stepehen Hawking.
Diagnosed with Lou Gehrig's disease at 21, Hawking, now 70, relies on a computerised device to speak. The new research could pave way for prosthetic devices in the brain returning the power of speech to those paralysed by injury or disease.
Researchers followed 11 epilepsy patients who had electrodes implanted in their brains to pinpoint the origin of their seizures, with neuron activity as they uttered one of five vowels or syllables containing the vowels recorded . They found two areas , the superior temporal gyrus and a region in the medial frontal lobe, housing neurons related to speech and attuned to vowels.
Neurons in the superior temporal gyrus, responsible for processing sounds responded to all the vowels, whereas those that fired exclusively for only one or two vowels were found in the medial frontal region involved in memory.
"We know that brain cells fire in a predictable way before we move our bodies," Dr Itzhak Fried, of University of California, said. "We hypothesized that neurons would also react differently when we pronounce specific sounds. If so, we may one day be able to decode these unique patterns of activity in the brain and translate them into speech," Fried said.
"Once we understand the neuronal code underlying speech, we can work backwards from brain-cell activity to decipher speech. This suggests an possibility for people who are physically unable to speak," said Fried.
Doctors hail paralysis breakthrough
From SARAH CHALMERS, in New York
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Scientists last night claimed a breakthrough in the treatment of paralysis.
It involves the use of stem cells from human embryos, a practice which has been shrouded in controversy.
In what is believed to be the first successful experiment of its kind, researchers at Johns Hopkins University in Baltimore say they have used the cells to partially cure paralysed laboratory mice.
The team hope to experiment on human paralysis sufferers within three years.
The mice were first infected with a virus which damaged nerve cells in their spines, leaving them paralysed. The resulting condition was similar to a disease suffered by humans called amyotrophic lateral sclerosis, or motor neurone disease.
The disease claimed the lives of actor David Niven and former England football manager Don Revie. Professor Stephen Hawking is a sufferer. The mice then had a solution containing human embryonic stem cells infused into their spinal fluid.
The cells migrated to the area of the damaged spinal cord and developed as healthy new nerve cells. They also released proteins that spurred the regeneration of normal nerve cells. Scientists believe that if the experiment works using human cells in mice, then it has a strong chance of success in humans.
Embryonic stem cells are the basic building blocks of body tissue. They can develop into any of the body's different components.
Neurologist Douglas Kerr, who led the experiment, said: 'The majority of the animals recovered some function. 'They are not completely normal but they can begin to move their hind limbs under them and some can bear weight.'
The extraordinary progress of the mice will challenge critics of stem cell research who have argued that the work has not yielded the breakthroughs promised by scientists. It comes at a time when President Bush is trying to decide whether or not to allow federal funding for such research.
The Johns Hopkins project was financed by Project ALS, a New York-based charity dedicated to finding a cure for the condition.
Dr Kerr and colleague Professor John Gearhart isolated the primitive human stem cells from five to nine week- old human foetuses. The foetuses had been selectively aborted after IVF treatment resulted in multiple pregnancies.
Professor Gearhart said the experiment proved that embryonic stem cells can be used to treat diseases in which nerve cells have been damaged and do not normally heal or regrow. Dr Kerr added: 'We are being cautiously aggressive. We want to advance as fast as possible.'
More than 200 scientists and doctors attending a genetics meeting in Bar Harbor, Maine, were due to see a dramatic video clip of the partially cured mice last night.
Supporters of embryonic stem cell research hope this latest development will help sway President Bush. Bush is still considering his decision but is thought to feel uneasy about the use of human embryos in such work. On his European tour this week he met the Pope, who has condemned stem cell research as 'devaluing human life.
Read more: http://www.dailymail.co.uk/health/article-62919/Doctors-hail-paralysis-breakthrough.html#ixzz24SyoLiWB
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