Graphene sensors: introduction and market status - Page 36

Researchers at Purdue University, the University of Michigan and Pennsylvania State University have combined graphene with a (comparatively much larger) silicon carbide substrate, creating graphene field-effect transistors which can be activated by light. This may lead to the development of highly sensitive graphene-based optical devices, an advance that could bring applications from imaging and displays to sensors and high-speed communications.

A typical problem of graphene-based photodetectors is that they have only a small area that is sensitive to light, limiting their performance. In typical graphene-based photodetectors demonstrated so far, the photoresponse only comes from specific locations near graphene over an area much smaller than the device size, the team said. However, for many optoelectronic device applications, it is desirable to obtain photoresponse and positional sensitivity over a much larger area. The researchers tackled exactly this in their new work.

Nanomedical Diagnostics announced a partnership with Rogue Valley Microdevices to deliver their graphene-based biosensors, AGILE R100. The partnership between Nanomedical Diagnostics and Rogue Valley Microdevices will open the novel sensing technique to any pharmaceutical company seeking to characterize biomolecules quickly and easily.

The AGILE R100 is designed to provide biophysical data to pharmaceutical and biotherapeutics companies seeking more informed decisions earlier in the drug discovery process. However, the company also plans a significant impact on the healthcare industry with innovative new products that enable cutting-edge life science research, drug discovery applications, and diagnostic and health monitoring platforms.

Zenyatta Ventures has announced that a team of scientists at Lakehead University in Canada has made significant progress in developing sensing applications with the first graphene oxide (GO) produced from the Company’s Albany graphite.

The team has developed a novel one-pot synthesis of fluorine functionalized graphene oxide (F-GO) which can be used in many energy, environmental and electrochemical sensing applications. The produced F-GO has been tested for the simultaneous detection of various toxic metal ions (e.g. mercury, lead, cadmium and copper) and a substantial improvement in the electrochemical sensing performance was achieved in comparison with GO.

Researchers in India and Japan have developed an improved method for using graphene-based transistors to detect disease-causing genes.

The team improved sensors that can detect genes through DNA hybridization, which occurs when a 'probe DNA' combines with its complementary 'target DNA.' Electrical conduction changes in the transistor when hybridization occurs. The improvement was done by attaching the probe DNA to the transistor through a drying process. This eliminated the need for a costly and time-consuming addition of 'linker' nucleotide sequences, which have been commonly used to attach probes to transistors.

Researchers at the King Abdullah University of Science and Technology (KAUST) have created graphene electrodes that function as effective biosensors, by using a laser inscribe patterns into a polymer sheet. The laser scribing technique locally heats parts of a flexible polyimide polymer to 2500 degrees Celsius or more to form carbonized patterns of patches on the surface that act as electrodes.

The black patches are about 33-micrometers thick, with a highly porous nature that allows molecules to permeate the material. Inside the patches, the graphene sheets have exposed edges that are effective at exchanging electrons with other molecules. "Graphene-based electrodes with more edge-plane sites are effectively better than those relying on carbon or carbon-oxygen sites in the plane of the material," said a member of the KAUST team.

Researchers from the Graphene Flagship, working at the University of Cambridge (UK), Emberion (UK), the Institute of Photonic Sciences (ICFO; Spain), Nokia UK, and the University of Ioannina (Greece) have developed a novel graphene-based pyroelectric bolometer - an infrared (IR) detector with record high sensitivity for thermal detection, capable of resolving temperature changes down to a few tens of µK. This work may open the door to high-performance IR imaging and spectroscopy.

The technology is focused on the detection of the radiation generated by the human body and its conversion into a measurable signal. The key point is that using graphene, the conversion reaches performance more than 250 times better than the best sensor already available. But the high sensitivity of the detector could be of use for spectroscopic applications beyond thermal imaging. With a high-performance graphene-based IR detector that gives a strong signal with less incident radiation, it is possible to isolate different parts of the IR spectrum. This is of key importance in security applications, where different materials explosives, for instance can be distinguished by their characteristic IR absorption or transmission spectra.

In its latest quarterly review, Talga Resources reported interesting highlights such as graphene battery anode testing and work with the IIT on graphene-based sensors.

On the battery front, Talga is conducting a testing program with the University of Warwick, UK, for its graphite products to be used in anodes of Li-ion batteries. In addition to graphite, this program is also testing water-based, rather than toxic solvent-based, graphene anode formulations. The Talga aqueous graphene-based formulations will also be tested under roll-to-roll coating conditions which are suitable for commercial scale battery anode manufacture.

A graphene dress was showcased at the Trafford Centre in Manchester. The dress came out of a partnership involving wearable tech pioneers Cute Circuit and the National Graphene Institute at the University of Manchester.

The dress has, according to its designers, ‘futuristic features including a graphene sensor which tracks the model's breathing, adapting its LED lighting to breathing patterns, and utilizing its translucent graphene circuitry.’ This means that it will change color according to the wearer's breathing rate - glowing purple upon fast breaths while slow and turquoise when breathing slowly.

A team of researchers from Exeter’s Centre for Graphene Science have developed a method for creating entire device arrays directly on the copper substrates used for the commercial manufacture of graphene. Complete and fully-functional devices can then be transferred to a substrate of choice, such as silicon, plastics or even textiles.

This new approach is simpler than conventional ways of producing graphene-based devices, and could lead the way to using simple and cheap-to-produce graphene devices for various applications, from gas and bio-medical sensors to touch-screen displays.

Researchers at the University of Texas have developed a graphene-based health sensor that attaches to the skin like a temporary tattoo and takes measurements with the same precision as bulky medical equipment. The graphene tattoos are said to be the thinnest epidermal electronics ever made. They can measure electrical signals from the heart, muscles, and brain, as well as skin temperature and hydration.

The research team hopes to integrate these sensors applications like consumer cosmetics, in addition to providing a more convenient replacement for existing medical equipment. The sensor takes advantage of graphene's mechanical invisibility - when the sensor goes on the skin, it doesn’t just stay flat—it conforms to the microscale ridges and roughness of the epidermis.