Graphene sensors: introduction and market status - Page 17

Caltech researchers have developed a new type of multiplexed test (a test that combines multiple kinds of data) with a low-cost sensor that may enable the at-home diagnosis of a COVID infection through rapid analysis of small volumes of saliva or blood, without the involvement of a medical professional, in under 10 minutes.

When attached to supporting electronics, the sensor can wirelessly transmit data to the user's cell phone through Bluetooth. Credit: Caltech, image from Phys.org

The research was conducted in the lab of Wei Gao, assistant professor in the Andrew and Peggy Cherng department of medical engineering. Previously, Gao and his team developed wireless sensors that can monitor conditions such as gout, as well as stress levels, through the detection of extremely low levels of specific compounds in blood, saliva, or sweat.

It was recently reported that Edmonton International Airport (YEG) will host a trial for a new graphene-based COVID-19 testing technology that can produce results in seconds. The trials will be executed in partnership with GLC Medical, a subsidiary of Graphene Leaders Canada (GLC).

The test is conducted with a handheld unit that takes a saliva sample from a person and is expected to tell if someone has COVID-19 in under one minute, compared to other tests with longer laboratory-based waiting periods for results. This test promises many advantages, from its ease of use to the elimination of the nasal swab to direct virus detection.

National University of Singapore (NUS) scientists have developed a sensitive graphene-enhanced 2D magnetic field sensor, which can potentially improve the detection of nanoscale magnetic domains for data storage applications.

Magnetoresistance (MR), the change in the electrical resistance of a material due to the influence of an external magnetic field, has been widely used in magnetic sensors, magnetic memories and hard disk drives. However, in traditional 3D material-based magnetic sensors that use giant MR (GMR) or tunneling MR (TMR) spin-valves, the detectable signal of the magnetic field decays exponentially with the thickness of its sensing layer. This limits the spatial resolution and sensitivity of the sensors. Therefore, a 2D-based sensor can potentially improve the detection of minuscule magnetic fields, as the decay is limited to only one atomic layer thickness.

King Abdullah University of Science and Technology (KAUST) and University of California Berkeley researchers have found that graphene-based sensors can perform in harsh environments that are inhospitable to other existing technologies.

The structure of graphene sensors for pH (top left), salinity (lower left) and temperature (right). Credit: 2020 Shaikh & Hussain, from Phys.org

"Graphene has been projected as a miracle material for years now, but its application in harsh environmental conditions was unexplored," says Sohail Shaikh, who has developed the new sensors, together with KAUST's Muhammad Hussain. "Existing sensor technologies operate in a very limited range of environmental conditions, failing or becoming unreliable if there is much deviation," Shaikh adds.

In June 2020, Paragraf entered into a working partnership with the Magnetic Measurement section at CERN, the European Organization for Nuclear Research, to demonstrate how new opportunities for magnetic measurements are opened up through the unique properties of its graphene sensor, particularly its negligible planar Hall effect. Now, Paragraf has demonstrated the ability of its graphene Hall Effect sensors to withstand high levels of radiation.

This conclusion, based on testing from the National Physical Laboratory (NPL), proves that ‘unpackaged’ Hall Effect sensors can be used in high-radiation environments such as space. The project was funded by Innovate UK, the UK’s innovation agency.

A recent study by researchers at Gauhati University, Indian Institute of Technology Bombay and DAIICT in India has demonstrated a soil moisture sensor made from graphene quantum dots, which are nanometer-sized fragments of graphene.

Water sensors are vital for various agriculture applications, like keeping track of the watering schedule for a large number of plants, such as for a field of crops. Soil moisture sensors measure the water content in the soil to avoiid crop destruction by under or over watering the field.

Following a $7.8 Million Series A-1 financing announced in March 2019, Cardea, (formerly called Nanomedical Diagnostics), a U.S-based manufacturer of a biology-enabled transistor technology made from graphene-based biosensors, now announced another $7.5 Million raised in the Series A2 Financing.

The capital will help accelerate the growth and development of the Company’s proprietary Tech+Bio Infrastructure and chipsets that enable Cardea’s Innovation Partners to bring Powered by Cardea" products to market with features and competitive advantages Cardea defines as "never seen before".

Researchers at Penn State, Northeastern University and five universities in China have developed and tested a stretchable, wearable gas sensor for environmental sensing.

The sensor combines a newly developed laser-induced graphene foam material with a unique form of molybdenum disulfide and reduced-graphene oxide nanocomposites. The researchers were interested in seeing how different morphologies of the gas-sensitive nanocomposites affect the sensitivity of the material to detecting nitrogen dioxide molecules at very low concentration. To change the morphology, they packed a container with very finely ground salt crystals.

Archer Materials has progressed its graphene-based biosensor technology development by successfully prototyping key device hardware using additive manufacturing (3D printing).

Graphene-based biosensor devices 2D printed on a circuit board that has been incorporated into the custom-designed and 3D printed cartridge made from ABS. The cartridge is opened and the interior is shown.

The cartridges were reportedly printed using acrylonitrile butadiene styrene (ABS), a robust engineering plastic, in less than 2 hours and with low costs, with the cartridges weighing about 13 grams (similar to a AAA battery) and measuring a few centimetres in size (palm size).

Cornell researchers, led by Katja Nowack, assistant professor of physics, used an ultrathin graphene and hexagonal boron nitride 'sandwich' to create a tiny magnetic field sensor that can operate over a greater temperature range than previous sensors, while also detecting miniscule changes in magnetic fields that might otherwise get lost within a larger magnetic background.

Nowack's lab specializes in using scanning probes to conduct magnetic imaging. One of their go-to probes is the superconducting quantum interference device, or SQUID, which works well at low temperatures and in small magnetic fields.