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Rapid synthesis of graphene oxide nanosheets

August 17, 2014



Rapid synthesis of graphene oxide nanosheets Science & Technology Desk



Using ultrasonic irradiation, researchers at Ferdowsi University of Mashhad in northeastern Iran presented a new method for the rapid synthesis of graphene oxide nanosheets.

Graphene and graphene oxide are used in producing electronic devices, fuel cells, energy storage and photocatalytic activities.

The synthesis of graphene oxide nanosheets was carried out rapidly under ultrasonic bath irradiation.

Results of the study indicated that the ultrasonic bath method even with low intensity has a fundamental role in the synthesis of graphene oxide nanosheets and it is relatively fast, simple, cost-effective and efficient.

Asma Esmaeili, PhD student in chemistry at the university, and Mohammad Hassan Entezari, a faculty member of the university, researched the project.





New material enhances fast,

accurate DNA sequencing

An Iranian student at the University of Illinois at Urbana-Champaign Amir Barati-Farimani, along with his colleagues, has found that a DNA molecule passes through a nanopore in a sheet of molybdenum disulfide, a material that is better than graphene at reading the DNA sequence.

Gene-based personalized medicine has many possibilities for diagnosis and targeted therapy, but one big bottleneck: the expensive and time-consuming DNA-sequencing process, ISNA wrote.

Now the researchers have found that nanopores in the material molybdenum disulfide (MoS2) could sequence DNA more accurately, quickly and inexpensively than anything yet available.

A nanopore is a very tiny hole drilled through a thin sheet of material. The pore is just big enough for a DNA molecule to thread through. An electric current drives the DNA through the nanopore and the fluctuations in the current as the DNA passes through the pore tell the sequence of the DNA, since each of the four letters of the DNA alphabet—A, C, G and T—are slightly different in shape and size.

Most materials used for nanopore DNA sequencing have a sizable flaw: They are too thick. Even a thin sheet of most materials spans multiple links of the DNA chain, making it impossible to accurately determine the exact DNA sequence.

Graphene has become a popular alternative, since it is a sheet made of a single layer of carbon atoms. In other words, only one base at a time goes through the nanopore.

Unfortunately, graphene has its own set of problems, the biggest being that the DNA sticks to it. The DNA interacting with the graphene introduces a lot of noise that makes it hard to read the current, like a radio station marred by loud static.

"MoS2 is a competitor of graphene in terms of transistors, but we showed here a new functionality of this material by showing that it is capable of biosensing," said graduate student Amir Barati Farimani, the first author.

The key to the success of the complex MoS2 simulation and analysis was the Blue Waters supercomputer, located at the National Center for Supercomputing Applications at the U of I.

"The ultimate goal of this research is to make some kind of home-based or personal DNA sequencing device," Barati Farimani said.

"We are on the path to get there, by finding the technologies that can quickly, cheaply and accurately identify the human genome. Having a map of your DNA can help to prevent or detect diseases in the earliest stages of development. If everybody can cheaply sequence so they can know the map of their genetics, they can be much more alert to what goes on in their bodies."


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Source: Iran Daily


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