Graphene sensors: introduction and market status - Page 18

Researchers at the Fraunhofer Institute for Reliability and Microintegration IZM have joined forces with partners in industry and healthcare to develop a graphene oxide based sensor platform to detect acute infections such as sepsis or the antibodies against the coronavirus within minutes.

The Graph-POC graphene oxide-based biosensor. (Image: Volker Mai, Fraunhofer IZM)

The current situation with the COVID 19 pandemic underscores the importance of detecting infections quickly and accurately to prevent further spread. Today, symptoms provide the clues that help diagnose viral or bacterial infections. However, many infections have similar symptoms, so these signs can easily be misread and the disease misdiagnosed. Blood tests provide certainty, but laboratories only carry these out when prescribed by the family physician. By the time the results arrive from the lab, doctors have often prescribed an antibiotic that may well be unnecessary.

Researchers at Iowa State University and Northwestern University have developed graphene sensors that are printed with high-resolution aerosol jet printers on a flexible polymer film and tuned to test for histamine, an allergen and indicator of spoiled fish and meat.

Image courtesy of Jonathan Claussen, taken from Iowa State University's website

The U.S. Food and Drug Administration has set histamine guidelines of 50 parts per million in fish, while the sensors were found to detect histamine down to 3.41 parts per million. This validates that the sensors are more than sensitive enough to track food freshness and safety.

The MULTIMAL research project is developing a small device that can be used to rapidly identify malaria parasites using saliva samples, without the need for lab equipment. MULTIMAL is one of eight projects exploring new uses for graphene with support from ATTRACT, a €20 million EU-funded, CERN-led consortium, which has awarded 170 grants worth €100,000 each for one-year proof-of-concept technology projects.

Today’s portable malaria testing kits are just above flipping a coin, because they are right only 60 percent of the time, says MULTIMAL principal investigator Jérôme Bôrme. The disease, which the World Health Organisation says killed 435,000 people in 2017 (nearly all of them in Africa), is caused by five species of parasite that can be easily identified in a lab. But treating the disease in remote towns and villages is difficult because of the lack of reliable portable testing kits, explains Bôrme, MULTIMAL’s principal investigator and staff researcher at the International Iberian Nanotechnology Laboratory in Portugal, which runs MULTIMAL in collaboration with the University of Minho.

Paragraf has 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.

Paragraf and CERN scientists setting up the graphene Hall sensor for performance evaluation in the reference dipole magnet of CERN’s magnetic measurement section. Credit: Paragraf/CERN

The Magnetic Measurements section at CERN is in charge of testing magnets for these accelerators using the latest-available techniques and instruments. High precision and reliable measurements are performed for many of CERN’s ongoing projects, and therefore the team is always on the lookout for new sensors and transducers for improving their measurement methods and accuracy.

Archer Materials has reported that it is making progress with its graphene-based biosensor technology with recent work spanning technology development, commercialization and patent prosecution.

This work includes the development of portable hardware to interface with Archer’s biosensor technology with simplified sensor response.

Researchers at the University of Sussex have developed an ultra-sensitive graphene-enhanced sensor that can stretch up to 80 times higher strain than strain gauges currently on the market and shows resistance changes 100 times higher than the most sensitive materials in research development.

Stretching and twisting the ultra-sensitive strain sensors. Credit: University of Sussex

The research team believes the sensors could bring new levels of sensitivity to wearable tech measuring patients’ vital signs and to systems monitoring buildings and bridges’ structural integrity.

The Graphene Flagship has announced 16 New FLAG-ERA projects, that cover a broad range of topics, from fundamental to applied research. These projects which will become Partnering Projects of the Graphene Flagship receiving around €11 million in funding overall.

Bringing together a diverse range of European knowledge and expertise, FLAG-ERA is an ERA-NET (European Research Area Network) initiative that aims to create synergies between new research projects and the Graphene Flagship and Human Brain Project.

An international team of scientists, led by the Universities of Surrey and Sussex, has developed graphene-enhanced color-changing, flexible photonic crystals that could be used to develop sensors that warn when an earthquake might strike next.

Optical images and internal microstructure of colloidal crystals enhanced with graphene. Image from Advanced Functional Materials

The wearable, robust and low-cost sensors can respond sensitively to light, temperature, strain or other physical and chemical stimuli making them an extremely promising option for cost-effective smart visual sensing applications in a range of sectors including healthcare and food safety.

A research team led by Juan Casanova and Eduard Llobet from the Departamento de Ingeniería Electrónica, Eléctrica y Automática at the Universitat Politècnica de València (URV), used graphene and perovskites to create a nanosensor that detects nitrogen dioxide with 300% improved sensitivity.

The team used graphene that is hydrophobic (water and moisture-resistant) and sensitive in gas detection, but with some limitations: it is not very selective and its sensitivity declines over time. In addition, the researchers used perovskites, a crystalline-structure material commonly used in the field of solar cells. However, they quickly deteriorate when they are exposed to the atmosphere. That's the reason why the team decided to combine perovskites with a hydrophobic material able to repel water molecules - in order to prove they can prevent or slow down their deterioration.

Scientists from the Moscow Institute of Physics and Technology, Skoltech, and the Russian Academy of Sciences Joint Institute for High Temperatures have conducted a theoretical study of the effects of defects in graphene on electron transfer at the graphene-solution interface. Their calculations show that defects can increase the charge transfer rate by an order of magnitude.

Moreover, by varying the type of defect, it is possible to selectively catalyze the electron transfer to a certain class of reagents in solution. This can prove very useful for creating efficient electrochemical sensors and electrocatalysts.