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Volume 94 Issue 13 | p. 5 | News of The Week
Issue Date: March 28, 2016 | Web Date: March 25, 2016

Graphene patch could help patients manage diabetes

Wearable, dual-function device monitors glucose in sweat and delivers drugs through skin
Department: Science & Technology
News Channels: Analytical SCENE, Materials SCENE, Nano SCENE, Biological SCENE
Keywords: diagnostics, electronic materials, diabetes, glucose monitoring, graphene
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A wearable patch combines glucose-sensing components (top) and a drug delivery system (bottom) to control blood glucose levels.
Credit: Hui Won Yun, Seoul National University/Nat. Nanotechnol.
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A wearable patch combines glucose-sensing components (top) and a drug delivery system (bottom) to control blood glucose levels.
Credit: Hui Won Yun, Seoul National University/Nat. Nanotechnol.

A wearable, graphene-based patch could one day maintain healthy blood glucose levels in people by measuring the sugar in sweat and then delivering the necessary dose of a diabetes drug through the skin (Nat. Nanotechnol. 2016, DOI: 10.1038/nnano.2016.38).

The device takes scientists a step closer to the “coveted prize” in diabetes care: a noninvasive method to monitor and control blood glucose levels, writes Richard Guy of the University of Bath in a commentary about the work.

For the new patch, the researchers, led by Dae-Hyeong Kim of Seoul National University, decided to detect glucose in sweat because previous studies had shown that levels of the sugar in perspiration match those in blood. Other groups have also developed devices that can analyze biomolecules in sweat (C&EN, Feb. 1, page 11).

The new device uses layers of the fluoropolymer Nafion to absorb sweat and carry it toward the device’s sensors, which are built on modified graphene. The team doped the graphene with gold atoms and functionalized it with electrochemically active materials to enable reactions needed to detect glucose.

In the patch’s glucose sensors, the enzyme glucose oxidase reacts with the sugar and produces hydrogen peroxide, which, through an electrochemical reaction, extracts current from the doped graphene. This produces an electrical signal proportional to the amount of glucose present. The patch also contains pH and temperature sensors that help ensure that the glucose sensor’s signals accurately reflect the sugar’s concentration in sweat.

When two healthy volunteers wore the patch, the measured glucose levels—including spikes after meals—matched those from a commercial glucose meter. To monitor the levels, the patch sent its sensor signals to a device that analyzed them and then wirelessly relayed the data to a smartphone.

The drug delivery half of the patch consists of an array of 1-mm-tall polymer microneedles that pierce the skin. Each needle is made from a mixture of the diabetes drug metformin and a dissolvable polymer, polyvinyl pyrrolidone. And the needles are coated with a layer of tridecanoic acid. A gold and graphene mesh sits on top of the needle array and serves as a heater that can melt the coatings. Once the tridecanoic acid melts, the needle dissolves in the skin and releases its drug payload.

When researchers applied just the drug delivery component to the stomachs of diabetic mice, they could deliver enough metformin to lower the animals’ elevated blood glucose levels by more than 50% in six hours.

Guy thinks the sensor portion of the patch is closer to real-world use than the drug delivery component. To make the drug delivery system practical, he says, the researchers must make the microneedle array as small as possible. That means they must find a drug that’s effective at low doses.

As for the glucose detection half of the device, Guy wonders how often a user would have to calibrate the sensors to ensure accurate readings.

Still, he calls the patch an impressive proof of concept.

This article has been translated into Spanish by Divulgame.org and can be found here.

 
Chemical & Engineering News
ISSN 0009-2347
Copyright © American Chemical Society
Comments
Gary Huber  (Thu Mar 24 18:17:15 EDT 2016)
I have a hard time seeing how the required amount of metformin could be delivered through microneedles. I take it in the form of two big horse-pills every day.
Charlene rombs  (Thu Mar 24 18:22:23 EDT 2016)
How can I be a volunteer to try this out
jamel  (Fri Mar 25 17:01:58 EDT 2016)
are they on for sale if yes where can i buy it please.
Dr. V..K. Varshney  (Sat Apr 02 13:01:01 EDT 2016)
Excellent research which is of great benefit to the diabetic patients. Congratulations to the innovators of this innovation. I wish all the best to the researchers for speedy commercialization of the product.


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