Transistors - Page 3

GrapheneDX, General Graphene Corporation and Sapphiros have announce a strategic partnership to industrialize graphene-based biosensors for medical devices used to diagnose a variety of diseases at the point-of-care and in consumer settings.

GrapheneDx is an in vitro diagnostics company focused on improving diagnostic capability at the point-of-care and in consumer settings. The company is an expert in functionalizing graphene to create graphene field effect transistors (GFETs), which are biosensors that can be used to detect disease in biological samples. GrapheneDx's medical devices are designed to provide lab-quality accuracy, deliver results in less than 5 minutes and be simple enough to be performed both at the point of care and by patients without the supervision of a medical professional. The company's GFET platform is versatile, demonstrating performance across a variety of disease states (sexually transmitted infections, respiratory disease, cardiac disease, concussion and others) and sample types (stool, urine, swabs, blood, etc.), with little or no sample preparation. Additionally, the platform is capable of multiplexing numerous analytes concurrently with a single patient sample. GrapheneDx's first tests will be for the diagnosis of sexually transmitted infections, including Chlamydia and Gonorrhea, using a noninvasive, easy to collect urine sample.

Scientists from Imperial College London and Catania University & CNR-IMM have developed a novel graphene ink that can be used to detect a variety of chemical substances when layered on top of commercially available printed circuit boards (PCBs) as a thin film.

In their recent paper, the team demonstrated a novel and versatile sensing platform, based on electrolyte-gated graphene field-effect transistors, for easy, low-cost and scalable production of chemical sensor test strips. The Lab-on-PCB platform is enabled by low-boiling, low-surface-tension sprayable graphene ink deposited on a substrate manufactured using a commercial printed circuit board process. 

Researchers from the University of California Santa Cruz, University of Manchester and Japan's International Center for Materials Nanoarchitectonics and National Institute for Materials Science have used a scanning tunnelling microscope to create and probe single and coupled electrostatically defined graphene quantum dots, to investigate the magnetic-field responses of artificial relativistic nanostructures.

Trapped electrons traveling in circular loops at extreme speeds inside graphene quantum dots are highly sensitive to external magnetic fields and could be used as novel magnetic field sensors with unique capabilities. Although graphene electrons do not move at the speed of light, they exhibit the same energy-momentum relationship as photons and can be described as "ultra-relativistic." When these electrons are confined in a quantum dot, they travel at high velocity in circular loops around the edge of the dot.

Researchers from Graphenea, Ikerbasque, BCMaterials, Center for Cooperative Research in Biomaterials (CIC biomaGUNE) of the Basque Research and Technology Alliance (BRTA), University of the Basque Country UPV-EHU, University of Trieste and Universidade da Coruña recently reported a graphene field effect transistors (GFET) array biosensor for the detection of SARS-CoV-2 spike protein, using the human membrane protein involved in the virus internalisation: angiotensin-converting enzyme 2 (ACE2).

By finely controlling the graphene functionalization, by tuning the Debye length, and by deeply characterizing the ACE2-spike protein interactions, the team managed to detect the target protein with an extremely low limit of detection (2.94 aM).

Graphenea recently upgraded its mGFET line of products with a built-in reservoir for liquids. This enhancement increases ease of use for biosensing and implementation in clinical testing and rapid screening.

The mGFET product line is designed to minimize barriers to adoption of graphene as a biosensor. The product was launched at the same time as the Graphenea Card, a socket for housing the mGFET and interfacing with measurement electronics. The addition of the built-in reservoir lets the user focus on the biochemistry, without worrying about producing the graphene or the sensor, or about interfacing.

Researchers from Japan's Tohoku University and RIKEN have successfully detected terahertz waves with fast response and high sensitivity at room temperature. 

On the electromagnetic spectrum, which comprises everything from radio waves to X-rays and gamma rays, there is a deadzone where conventional electronic devices can hardly operate. This deadzone is occupied by terahertz waves. With wavelengths of approximately 10 micrometers to 1 millimeter, terahertz waves are unique amongst electromagnetic waves. Their vibration frequency overlaps with the molecules that make up matter, and they allow for the detection of substances, since almost every molecule operating in the terahertz band has a fingerprint spectrum. Technologies capable of harnessing the power of terahertz waves could have massive significance for the development of spectroscopy, imaging, and 6G and 7G technologies.

In June 2022, Graphenea launched its latest product out of its Graphene Foundry, the mGFET, fully-packaged mini graphene-based field effect transistors.

Graphenea now updates that the market demand for these products has been excellent, and it has run out of stock. The company is now working to produce more mGFET devices and restock.

The mGFETs are Graphenea's highest value-chain products, which are manufactured and packaged in chip carriers, and can be used together with the Graphenea Card for seamless sensor development (which was released earlier in 2022, and has also seen very good reception in the industry).

Australia-based Archer Materials has developed a graphene-based field effect transistor (gFET) that can operate in wet environments. The gFET device is a sensing component which will be used in medical applications, like for digitizing biologically-relevant signals such as those from target analytes of viruses or bacteria. The biochip innovation will be integrated with advanced microfluidic systems to allow the manufacturing of mini lab-on-a-chip device platforms designed for medical diagnostics.

The company explained that the integration of gFETs with on-chip microfluidics potentially enables multiplexing, such as the ability to parallelize the detection of multiple biologically relevant targets in droplet-size liquid samples on a chip. The innovation can prevent liquids from shorting the integrated circuit, while simultaneously obtaining electronic signals using the liquid as part of the device. 

Researchers from University of Texas at Austin have developed an antibody (Ab)-modified graphene field effect transistor (GFET)-based biosensor for precise and rapid influenza A virus (IAV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) protein detection and differentiation.

The sensor chip that was developed comprised of four GFETs in a quadruple arrangement, separated by polydimethylsiloxane (PDMS) enclosures. Every quarter was biochemically functionalized with SARS-CoV-2 and IAV antigen-targeted Abs, one chemically passivated control, and one bare control. The third (chemically passivated) GFET was deployed to ensure that the results observed were due to Ab-antigen interaction rather than electronic fluctuations or drifts.

Researchers from The University of Texas at Austin and Sandia National Laboratories have developed graphene-based synaptic transistors for brain-like computers. These transistors are similar to synapses in the brain, that connect neurons to each other.

"Computers that think like brains can do so much more than today's devices," said Jean Anne Incorvia, an assistant professor at The University of Texas at Austin and the lead author on the paper. "And by mimicking synapses, we can teach these devices to learn on the fly, without requiring huge training methods that take up so much power."