Tag Archives: Anurag Kumar

Blood, tears, and urine for use in diagnostic tools

Frankly, I’d rather just spit into a cup or onto a slide for diagnostic tests than having to supply urine or have my blood drawn. I don’t think that day has arrived yet but scientists at Purdue University (Indiana, US) have made a breakthrough. From the Aug. 23, 2012 news item on ScienceDaily,

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 University 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.

The originating Aug. 20, 2012 Purdue University news release by Emil Venere provides details as to how this biosensor works,

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.”

In addition to diabetes testing, the technology might be used for sensing a variety of chemical compounds to test for other medical conditions.

Here’s a representation of the ‘rose petal’ nanosheets,

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. (Purdue University photo/Jeff Goecker)
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My most recent piece, prior to this, about less invasive diagnostic tests was this May 8, 2012 posting on a handheld diagnostic device that tests your breath for disease.