What is a sensor?
A sensor is a device that detects events that occur in the physical environment (like light, heat, motion, moisture, pressure, and more), and responds with an output, usually an electrical, mechanical or optical signal. The household mercury thermometer is a simple example of a sensor - it detects temperature and reacts with a measurable expansion of liquid. Sensors are everywhere - they can be found in everyday applications like touch-sensitive elevator buttons and lamp dimmer surfaces that respond to touch, but there are also many kinds of sensors that go unnoticed by most - like sensors that are used in medicine, robotics, aerospace and more.
Traditional kinds of sensors include temperature, pressure (thermistors, thermocouples, and more), moisture, flow (electromagnetic, positional displacement and more), movement and proximity (capacitive, photoelectric, ultrasonic and more), though innumerable other versions exist. sensors are divided into two groups: active and passive sensors. Active sensors (such as photoconductive cells or light detection sensors) require a power supply while passive ones (radiometers, film photography) do not.
Where can sensors be found?
Sensors are used in numerous applications, and can roughly be arranged in groups by forms of use:
- Accelerometers: Micro Electro Mechanical technology based sensors, used mainly in mobile devices, medicine for patient monitoring (like pacemakers) and vehicular systems.
- Biosensors: electrochemical technology based sensors, used for food and water testing, medical devices, fitness tracker and wristbands (that measure, for example, blood oxygen levels and heart rate) and military uses (biological warfare and more).
- Image sensors: CMOS (Complementary Metal-Oxide Semiconductor) based sensors, used in consumer electronics, biometrics, traffic and security surveillance and PC imaging.
- Motion Detectors: sensors which can be Infrared, Ultrasonic or Microwave/Radar technology. They are used in video games, security detection and light activation.
What is graphene?
Graphene is a two-dimensional material made of carbon atoms, often dubbed “miracle material” for its outstanding characteristics. It is 200 times stronger than steel at one atom thick, as well as the world’s most conductive material. It is so dense that the smallest atom of Helium cannot pass through it, but is also lightweight and transparent. Since its isolation in 2004, researchers and companies alike are fervently studying graphene, which is set to revolutionize various markets and produce improved processes, better performing components and new products.
Graphene and sensors
Graphene and sensors are a natural combination, as graphene’s large surface-to-volume ratio, unique optical properties, excellent electrical conductivity, high carrier mobility and density, high thermal conductivity and many other attributes can be greatly beneficial for sensor functions. The large surface area of graphene is able to enhance the surface loading of desired biomolecules, and excellent conductivity and small band gap can be beneficial for conducting electrons between biomolecules and the electrode surface.
Graphene is thought to become especially widespread in biosensors and diagnostics. The large surface area of graphene can enhance the surface loading of desired biomolecules, and excellent conductivity and small band gap can be beneficial for conducting electrons between biomolecules and the electrode surface. Biosensors can be used, among other things, for the detection of a range of analytes like glucose, glutamate, cholesterol, hemoglobin and more. Graphene also has significant potential for enabling the development of electrochemical biosensors, based on direct electron transfer between the enzyme and the electrode surface.
Graphene will enable sensors that are smaller and lighter - providing endless design possibilities. They will also be more sensitive and able to detect smaller changes in matter, work more quickly and eventually even be less expensive than traditional sensors. Some graphene-based sensor designs contain a Field Effect Transistor (FET) with a graphene channel. Upon detection of the targeted analyte’s binding, the current through the transistor changes, which sends a signal that can be analyzed to determine several variables.
Graphene-based nanoelectronic devices have also been researched for use in DNA sensors (for detecting nucleobases and nucleotides), Gas sensors (for detection of different gases), PH sensors, environmental contamination sensors, strain and pressure sensors, and more.
Commercial activities in the field of graphene sensors
In June 2015, A collaboration between Bosch, the Germany-based engineering giant, and scientists at the Max-Planck Institute for Solid State Research yielded a graphene-based magnetic sensor 100 times more sensitive than an equivalent device based on silicon.
In August 2014, the US based Graphene Frontier announced raising $1.6m to expand the development and manufacturing of their graphene functionalized GFET sensors. Their “six sensors” brand for highly sensitive chemical and biological sensors can be used to diagnose diseases with sensitivity and efficiency unparalleled by traditional sensors.
In September 2014, the German AMO developed a graphene-based photodetector in collaboration with Alcatel Lucent Bell Labs, which is said to be the world’s fastest photodetector.
In November 2013, Nokia’s Cambridge research center developed a humidity sensor based on graphene oxide which is incredibly fast, thin, transparent, flexible and has great response and recovery times. Nokia also filed for a patent in August 2012 for a graphene-based photodetector that is transparent, thin and should ultimately be cheaper than traditional photodetectors.
The latest graphene sensor news:
UK-based Paragraf has announced a new graphene Hall Effect sensor, said to be ideally suited to battery applications, such as the electric vehicle (EV) sector.
The graphene GHS01AT Hall Effect sensor is optimized for use in relatively low field environments and normal ambient temperatures. Bringing the magnetic field measurement resolution towards that of more complex magnetic sensors, yet with the small size and ease of use of a Hall sensor, it can address monitoring tasks that conventional technologies simply cannot provide an effective solution for.
GLC Medical (GLCM), a subsidiary of Graphene Leaders Canada (GLC), recently announced completion of development of the GLCM SARS-CoV-2 Insta-Test, delivering results in under 15 seconds, offering fast and easy to use solution to screen for COVID-19.
The Company stated that it sees potential for this new graphene-based biosensor to enable the world to regain a sense of freedom and bring “normal” back into its future.
Cardea Bio and the Georgia Tech Research Institute enter DARPA agreement to develop airborne SARS-CoV-2 sensors
The Defense Advanced Research Projects Agency (DARPA) recently awarded the Georgia Tech Research Institute (GTRI) an agreement, as part of their SenSARS program, to develop a sensing platform to detect airborne SARS-CoV-2 particles. Cardea Bio is a sub-contractor to this agreement.
This agreement will enable the two institutions to develop a real-time pathogen identification technology that can be applied to many different defense and civilian environmental monitoring applications.
Qurv Technologies, a Spain-based startup developing wide-spectrum image sensors based on graphene and quantum-dot technologies, has won the Imaging Sensors Technology Showcase at the Technology Unites Global Summit.
The Qurv wide-spectrum image sensor was recognized as the best imaging technology. The selection of winners (Infineon Technologies also won an award for its environmental sensor as the leading MEMS technology) was made from five finalists in each category in a vote by a committee of industry experts.
Grapheal raises almost $3 million for graphene-based biosensors, hopes to hit the market by end of 2021
Grapheal, a developer of graphene-based embedded biosensors for on-site diagnostics and remote patient monitoring, has announced that it has raised a total of EUR1.9 million (almost USD$3 million) in equity and non-dilutive sources, including seed financing from Novalis Biotech’s Acceleration Fund, several innovation grants, and Bpifrance convertible notes and loans.
The funds will be used to advance the commercialization of Grapheal’s flexible graphene-based biosensor technology. This sensing technology combines novel electronic nanomaterials, embedded wireless electronics, software data analysis, and medical cloud IoT technologies. The first two applications of the technology will be a new generation digital COVID-19 test (TestNPass) for rapid screening in high-traffic areas, such as airports, and a wound care digital assistant (WoundLAB) to improve the monitoring of hard-to-heal wounds. The funds will also be used to validate the two devices in the field and complete clinical studies, respectively.