Graphene sensors: introduction and market status - Page 29

University of Arkansas researchers are working together, with support from the National Institutes of Health, to make that prospect of graphene-based sensors that sequence a patient's genome to predict diseases more realistic. Steve Tung, professor of mechanical engineering, and Jin-Woo Kim, professor of biological engineering, have received a grant (of approximately $400,000) from the NIH's Human Genome Research Institute to develop nanoscale technology designed to make DNA sequencing faster, cheaper and easier.

The base of the research builds on the concept of nanochannel measurement, in which individual strands of DNA pass through a tiny channel. The passage of those strands interrupts an electrical current and a sensor detects the nature of the interruption, telling scientists which nucleotide has passed through the channel.

Rice University scientists have developed a simple way to create conductive, 3D objects made of graphene foam. The resulting objects may offer new possibilities for energy storage and flexible electronic sensor applications, according to Rice chemist Prof. James Tour.

The technique is an extension of groundbreaking work by the Tour lab that produced the first laser-induced graphene (LIG) in 2014 by heating inexpensive polyimide plastic sheets with a laser. The laser burns halfway through the plastic and turns the top into graphene that remains attached to the bottom half. LIG can be made in macroscale patterns at room temperature.

Researchers at the University of Pennsylvania have used graphene to increase the sensitivity of diagnostic devices, in particular those used to monitor and treat HIV. The team combined a trick of DNA engineering which involves an engineered piece of DNA called a hairpin, with biosensors, increasing the sensitivity of the sensors by a factor of 50,000 in less than an hour.

The biosensorsare made with graphene, and so can be used as an extremely sensitive way of detecting biological signals, measuring the current that flows through graphene surface in the presence of biomolecules. When DNA or RNA molecules bind to the graphene, it produces a big change in the conductivity of the atomically thin material, allowing the researchers to detect infections and to measure viral loads.

Researchers from the Indian Institute of Science (IISc), the Max Planck Institute for Intelligent Systems in Germany and the University of Stuttgart, Germany have developed a novel silver nanoparticle-graphene hybrid photodetector device with an increased ability to detect Ultraviolet light.

To enhance graphene's interaction with light, researchers have proposed several strategies. One of these strategies has been to sensitize the graphene with plasmonic nanostructures, to form a graphene-plasmonic hybrid system. Plasmonic nanoparticles are particles which show an increased interaction with light of wavelength larger than the particle itself. These particles are said to interact with light waves through an oscillation of their internal electric fields, as the light hits the particle. Previous studies have demonstrated enhanced visible and infrared light detection efficiency in graphene-plasmonics hybrid materials. However, these devices haven’t been efficient at detecting ultraviolet (UV) light.

Researchers at Hanyang University in South Korea have taken a significant step towards human-like touch sensing with a sensor made of a graphene-flake film supported on a robust polyethylene naphthalate substrate. They have combined an electric sensor with a machine-learning algorithm to create a device that can feel and distinguish different surface textures. The device could find use in virtual reality, robotics and medical prosthetics.

According to the team, machines can already recognize and replicate patterns associated with human speech and vision. Touch, however, is more complex to mimic because it relies on mechanoreceptors in the skin that sense tiny changes in pressure and vibrations when touching different surfaces.

Researchers at the Russia-based MIPT, MSPU and the University of Manchester revealed the mechanisms leading to photocurrent in graphene under terahertz radiation. The paper is said to put an end to a long-lasting debate about the origins of direct current in graphene illuminated by high-frequency radiation, and also sets the stage for the development of high-sensitivity terahertz detectors. Such detectors have applications in medical diagnostics, wireless communications and security systems.

In 2005, MIPT alumni Andre Geim and Konstantin Novoselov experimentally studied the behavior of electrons in graphene and found that electrons in graphene respond to electromagnetic radiation with an energy of quantum, whereas the common semiconductors have an energy threshold below which the material does not respond to light at all. However, the direction of electron motion in graphene exposed to radiation has long remained a point of controversy, as there is an abundance of factors pulling it in different directions. The controversy was especially stark in the case of the photocurrent caused by terahertz radiation.

Researchers from the Russia-based Moscow Institute of Physics and Technology ('MIPT') have developed biosensor chips of unprecedented sensitivity, which are based on copper combined with graphene oxide instead of the conventionally used gold. In addition to making the device somewhat cheaper, this innovation will facilitate the manufacturing process.

The Russian research team's biosensing chip reportedly achieved unmatched sensitivity, and yet its configuration is mostly standard and therefore compatible with existing commercial biosensors, e.g. Biacore, Reichert, BioNavis, or BiOptix.

Researchers at the Department of Chemistry of the University of Warsaw in Poland have developed a new graphene matrix, as a functional substrate for immobilizing enzymes, and the method of its preparation. The newly-patented graphene matrix may find applications in the food and medicine industries, like the production of biosensors and other electronic devices (eg. bands, tattoos).

Diagram of a lactate biosensor composed of a graphene matrix and a lactate oxidase enzyme, deposited on a carbon electrode

The invention is used as a stable system with high sensitivity, not only in analytical biosensors, but also in bio-fuel cells used in medicine, biology and chemical biocatalysis. The solution concerns the enzymatic (protein) sensor construction for detection of lactates, which can be used in the food industry and medicine for the production of biosensors.

Researchers at the India-based Uttarakhand Residential University, RI Instruments and Innovationin have developed a new graphene-based technology to prevent vehicles from operating if the driver is drunk. To be more exact, the jointly developed device will make driving difficult if the driver is in an inebriated condition or feeling drowsy or is speaking on the mobile phone.

The prototype will be based on graphene generated from waste products and wild grasses as one of the components. Graphene has an important role in the device as graphene-coated electrodes can catalyze the process of oxidation of ethyl alcohol into acetic acid. The concentration of alcohol will automatically disconnect the device, the team said.

Researchers at the Institute of Photonic Sciences (ICFO) in Spain, along with other members of the Graphene Flagship, have reached what they consider to be the ultimate level of light confinement - being able to confine light down to a space of one atom. This may pave the way to ultra-small optical switches, detectors and sensors.

Graphene keeps surprising us: nobody thought that confining light to the one-atom limit would be possible. It will open a completely new set of applications, such as optical communications and sensing at a scale below one nanometer, said ICREA Professor Frank Koppens at ICFO, who led the research.