Graphene Sensors

Graphene Trace, a UK-based startup that aims to use sensors to eradicate the problem of pressure ulcers, has been awarded a £300,000 grant by Innovate UK.

The startup believes its proprietary sensor technology for wheelchair users and hospital inpatients could reduce pressure ulcer onset by up to 95%. CEO Scott Dean said the grant will fund the creation of a prototype for its pressure ulcer prevention technology and bring it a step closer to going to market.

It is a known fact that animals require the integration of cues collected from multiple sensory organs to enhance the overall perceptual experience and thereby facilitate better decision-making in most aspects of life. However, despite the importance of multisensory integration in animals, the field of artificial intelligence (AI) and neuromorphic computing has primarily focused on processing unisensory information. This lack of emphasis on multisensory integration can be attributed to the absence of a miniaturized hardware platform capable of co-locating multiple sensing modalities and enabling in-sensor and near-sensor processing. 

a) A simplified abstraction of visual and chemical stimuli from male butterflies and visuo-chemical integration pathway in female butterflies. b) Butterfly-inspired neuromorphic hardware comprising of monolayer MoS₂ memtransistor-based visual afferent neuron, graphene-based chemoreceptor neuron, and MoS₂ memtransistor-based neuro-mimetic mating circuits. Image credit: Advanced Materials

In their recent study, researchers at Penn State University addressed this limitation by utilizing the chemo-sensing properties of graphene and the photo-sensing capability of monolayer molybdenum disulfide (MoS₂) to create a multisensory platform for visuochemical integration. 

Researchers at the University of Massachusetts and Massachusetts Institute of Technology (MIT) have successfully built a tissue-like bioelectronic mesh system integrated with an array of graphene sensors that can simultaneously measure both the electrical signal and the physical movement of cells in lab-grown human cardiac tissue.

A bioelectronic mesh, studded with graphene sensors (red), can measure the electrical signal and movement of cardiac tissue (purple and green) at the same time. Image credit: UMass Amherst
 

The tissue-like mesh can grow along with the cardiac cells, allowing researchers to observe how the heart’s mechanical and electrical functions change during the developmental process. The new device can be extremely useful for those studying cardiac disease as well as those studying the potentially toxic side-effects of many common drug therapies.

Researchers at the Liverpool School of Tropical Medicine (LSTM) will collaborate with ProMake, a material science and diagnostic company, as part of Innovate UK's Accelerated Knowledge Transfer Scheme. The new project will investigate how graphene technology could be utilized to rapidly detect infection and act as the basis for new medical diagnostics.

ProMake has developed a novel device prototype, the 'BioPod', a hand-held point-of-care diagnostic containing the graphene lab-on-a-chip (LOC) electrode. The LOC uses functionalized graphene, a super-strong and thin material laced with specific receptors, to detect a wide range of pathogens. The aim is to use the BioPod in the same way as lateral flow tests (LFTs), to test for COVID-19 and other pathogens. However, unlike LFTs, which provide quick results but with less accuracy than tests processed in the lab, the BioPod's advanced technology has the potential to be more accurate and easier to interpret.

Researchers from the Vietnam Academy of Science and Technology, VNU University of Science, Hanoi University of Science and Technology and the Russian Academy of Sciences have developed a biosensor that uses graphene electrodes modified by zinc oxide nanoparticles to measure Hypoxanthine (HXA), a material that can be used as a marker for the freshness of meat. The team demonstrated the sensor’s efficacy on pork meat.

The freshness of animal meat in the food industry is an essential property determining its quality and safety. With advanced technology capable of preserving food for extended periods of time, meat can be shipped around the globe and so there is a vital need for effective testing of its condition. Despite the technological advances keeping meat fresh for as long as possible, certain aging processes are unavoidable. Adenosine triphosphate (ATP) is a molecule produced by breathing and responsible for providing energy to cells. When an animal stops breathing, ATP synthesis also stops, and the existing molecules decompose into acid, diminishing first flavor and then safety. Hypoxanthine (HXA) and xanthine are intermediate steps in this transition. Assessing their prevalence in meat indicates its freshness.

Researchers at the University of Cambridge and the University of Warwick have developed a fully 3D-printed quantum dot/graphene-based aerogel sensor for highly sensitive and real-time recognition of formaldehyde at room temperature. Formaldehyde is a known human carcinogen that is a common indoor air pollutant. However, its real-time and selective recognition from interfering gases has thus far remained challenging, especially for low-power sensors suffering from noise and baseline drift. 

The new sensor uses artificial intelligence techniques to detect formaldehyde in real time at concentrations as low as eight parts per billion, far beyond the sensitivity of most indoor air quality sensors.

Scientists at the University of California San Diego have developed an ultra-sensitive graphene-based sensor that can detect extraordinarily low concentrations of lead ions in water. The device achieved a record limit of detection of lead down to the femtomolar range, which is said to be a million times more sensitive than previous sensing technologies.

The device in this study consisted of a single layer of graphene mounted on a silicon wafer. The researchers enhanced the sensing capabilities of the graphene layer by attaching a linker molecule to its surface. This linker serves as the anchor for an ion receptor and, ultimately, the lead ions.

University of Massachusetts Amherst researchers have received an award to develop a graphene-based sweat monitor tattoos that can be applied to the skin just like a temporary tattoo and assess the molecules present, such as cortisol. The tattoos will aim to give users better insight into their health and serve as a tool for researchers to discover new early indications of diseases.

“There are a lot of vital biomolecules that are present in sweat that we need to measure to really understand overall human performance and correlation to different diseases,” says research lead and assistant professor of biomedical engineering, Dmitry Kireev.

Researchers at Peking University, University of Science and Technology Beijing and Peking University Third Hospital have reported magnetically self-assembling graphene sensors. 

While wearable sensors can provide continuous, personalized health tracking beyond clinical visits, most devices today still have fixed designs targeting single applications, lacking versatility to address users' changing needs. The team's recent work could address this issue and enable modular, reconfigurable wearable electronics customized to individuals. 

University of California San Diego researchers have developed a neural implant capable of reading brain activity that could advance research into creating a brain-computer interface (BCI) without being overly invasive.

The new implant consists of a thin transparent strip made of a polymer with several graphene electrodes 20 micrometers in diameter, each of which is connected to a circuit board via tiny wires. The strip sits on the surface of the brain allowing it to detect neural activity consisting of electrical activity and calcium activity. Unlike previous methods, the chip allows scientists to conduct longer experiments without the need to have a subject fixed in place under a microscope.