Graphene-based Sensor Brings New Wrinkle to Wearables

Badge-sized device could offer continuous monitoring for a variety of diseases

2 min read
A microscope slide with a ring of light surrounding a black square surrounding a white rectangle.
Photo: Joseph Xu/Michigan Engineering

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The capabilities of wearable sensors seem to be expanding every day. However, for the most part these sensors have measured just physical attributes, like heart rate.

Now researchers at the University of Michigan have developed a graphene-based wearable sensor capable of detecting airborne chemicals that serve as indicators of medical conditions. For instance, the sensor could detect acetone, which is a biomarker for diabetes. Or it could detect abnormal levels of nitric oxide and oxygen, which would be an indicator of conditions such as high blood pressure, anemia, or lung disease.

“With our platform technology, we can measure a variety of chemicals at the same time, or modify the device to target specific chemicals. There are limitless possibilities,” said Zhaohui Zhong, an associate professor at the University of Michigan, in a press release.

The researchers had to take a novel approach to how the nanosensor detect chemicals. In research, which was published in the journal Nature Communications, the Michigan researchers developed a sensing mechanism based on detecting molecular dipoles.

This sensing mechanism stands in contrast to most other nanosensors, which are based on detecting a change in charge density due to a molecule binding to the sensor.

“Nanoelectronic sensors typically depend on detecting charge transfer between the sensor and a molecule in air or in solution,” said Girish Kulkarni, a doctoral candidate and one of the researchers, in a press release. “Instead of detecting molecular charge, we use a technique called heterodyne mixing, in which we look at the interaction between the dipoles associated with these molecules and the nanosensor at high frequencies.”

The researchers claim that the graphene made this sensing technique possible, resulting in extremely fast response times of tenths of a second as opposed to tens or hundreds of seconds in existing technology. In addition to fast response times the sensors are highly sensitive, capable of detecting molecules with a concentration of a few parts per billion.

With these graphene-based sensors, the researchers have been able to put an entire chromatography system on a single chip that is able to operate with very little power. With this setup, a badge-side device could be worn on the body to give continuous monitoring of health conditions.

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This CAD Program Can Design New Organisms

Genetic engineers have a powerful new tool to write and edit DNA code

11 min read
A photo showing machinery in a lab

Foundries such as the Edinburgh Genome Foundry assemble fragments of synthetic DNA and send them to labs for testing in cells.

Edinburgh Genome Foundry, University of Edinburgh

In the next decade, medical science may finally advance cures for some of the most complex diseases that plague humanity. Many diseases are caused by mutations in the human genome, which can either be inherited from our parents (such as in cystic fibrosis), or acquired during life, such as most types of cancer. For some of these conditions, medical researchers have identified the exact mutations that lead to disease; but in many more, they're still seeking answers. And without understanding the cause of a problem, it's pretty tough to find a cure.

We believe that a key enabling technology in this quest is a computer-aided design (CAD) program for genome editing, which our organization is launching this week at the Genome Project-write (GP-write) conference.

With this CAD program, medical researchers will be able to quickly design hundreds of different genomes with any combination of mutations and send the genetic code to a company that manufactures strings of DNA. Those fragments of synthesized DNA can then be sent to a foundry for assembly, and finally to a lab where the designed genomes can be tested in cells. Based on how the cells grow, researchers can use the CAD program to iterate with a new batch of redesigned genomes, sharing data for collaborative efforts. Enabling fast redesign of thousands of variants can only be achieved through automation; at that scale, researchers just might identify the combinations of mutations that are causing genetic diseases. This is the first critical R&D step toward finding cures.

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