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Center for Nanoscale Science renewed at $18 million for six years

Posted By Graphene Council, Wednesday, September 23, 2020
The Center for Nanoscale Science, a National Science Foundation Materials Science and Engineering Center (MRSEC), has again successfully renewed its NSF support in the highly competitive MRSEC program. The new iteration of the center encompasses two of NSF's Big Ideas -- "Quantum Leap" and "Harnessing the Data Revolution."

More than 20 Penn State faculty are involved in the MRSEC's two new interdisciplinary research groups (IRGs). IRG1, 2D Polar Metals and Heterostructures, is led by Joshua Robinson, professor of materials science and engineering and Jun Zhu, professor of physics. It pioneers new methods of encasing two-dimensional metals in graphene to achieve exceptional optical properties and intriguing potential for quantum devices and biosensing. Before the IRG's pioneering work, only gold among metals was known to resist oxidation in the air. Penn State researchers are now extending that critical property across wide swathes of the periodic table.

IRG2, Crystalline Oxides with High Entropy, is led by Jon-Paul Maria, professor of materials science and engineering and Ismaila Dabo, associate professor of materials science and engineering. It seeks to write a new chapter in the crystal chemistry rulebook by creating materials that take advantage of the enormous number of ways that different kinds of atoms can be arranged onto a common crystal lattice. This innovative technique enables Penn State researchers to put atoms into environments that they normally do not assume, with potential applications across a wide domain, from new energy materials to new quantum devices, guided by a close interplay of theory, computation, data and experiment.

"These two intriguing research directions define new materials platforms- whole classes of new materials - that are being pioneered here at Penn State," says Vin Crespi, the director of the Center for Nanoscale Science.

The MRSEC also provides career development opportunities for dozens of graduate students with a focus during this renewal on sustainability in research practice and outcomes. A recently launched educational website, "Mission: Materials Science," will expand its content and reach out to youth audiences through a new partnership with the local Discovery Space museum. Outreach through participation in summer science camps, STEM programs for students who are blind or visually impaired, and partnerships with universities that serve underrepresented students will remain core to the Center's mission.

Program Director for Education and Outreach Kristin Dreyer said, "The best and most effective messengers for communicating important science concepts to youth and public audiences and inspiring the next generation of materials scientists are current researchers themselves. My colleague, Tiffany Mathews, and I get to help make those opportunities happen and provide the necessary support for our members to do it successfully."

The Center for Nanoscale Science is among eight MRSECs successfully renewing their funding along with three new centers, and has been funded continuously since 2000.

According to NSF, "The U.S. economy and its competitiveness depend on innovation, an essential part of which is fueled by technological breakthroughs in basic research. Our comfort, work, and well-being depend on the development of new materials for anything ranging from smart electronics to implantable medical devices."

Tags:  biosensor  Center for Nanoscale Science  Graphene  Jon-Paul Maria  Joshua Robinson  National Science Foundation  Penn State  quantum material 

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Understanding electron transport in graphene nanoribbons

Posted By Graphene Council, Tuesday, September 15, 2020
Graphene is a modern wonder material possessing unique properties of strength, flexibility and conductivity whilst being abundant and remarkably cheap to produce, lending it to a multitude of useful applications -- especially true when these 2D atom-thick sheets of carbon are split into narrow strips known as Graphene Nanoribbons (GNRs).

New research published in EPJ Plus, authored by Kristians Cernevics, Michele Pizzochero, and Oleg V. Yazyev, Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne, Switzerland, aims to better understand the electron transport properties of GNRs and how they are affected by bonding with aromatics. This is a key step in designing technology such chemosensors.

"Graphene nanoribbons -- strips of graphene just few nanometres wide -- are a new and exciting class of nanostructures that have emerged as potential building blocks for a wide variety of technological applications," Cernevics says.

The team performed their investigation with the two forms of GNR, armchair and zigzag, which are categorised by the shape of the edges of the material. These properties are predominantly created by the process used to synthesise them. In addition to this, the EPFL team experimented p-polyphenyl and polyacene groups of increasing length.

"We have employed advanced computer simulations to find out how electrical conductivity of graphene nanoribbons is affected by chemical functionalisation with guest organic molecules that consist of chains composed of an increasing number of aromatic rings," says Cernevics.

The team discovered that the conductance at energies matching the energy levels of the corresponding isolated molecule was reduced by one quantum, or left unaffected based on whether the number of aromatic rings possessed by the bound molecule was odd or even. The study shows this 'even-odd effect' originates from a subtle interplay between the electronic states of the guest molecule spatially localised on the binding sites and those of the host nanoribbon.

"Our findings demonstrate that the interaction of the guest organic molecules with the host graphene nanoribbon can be exploited to detect the 'fingerprint' of the guest aromatic molecule, and additionally offer a firm theoretical ground to understand this effect," Cernevics concludes: "Overall, our work promotes the validity of graphene nanoribbons as promising candidates for next-generation chemosensing devices."

These potentially wearable or implantable sensors will rely heavily on GRBs due to their electrical properties and could spearhead a personalised health revolution by tracking specific biomarkers in patients.

Tags:  Biosensor  EPFL  Graphene  Graphene Nanoribbons  Healthcare  Kristians Cernevics  Michele Pizzochero  Oleg V. Yazyev  Sensors 

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Epitaxial Graphene-Based Biosensor Provides Rapid Detection of COVID-19

Posted By Graphene Council, Thursday, August 27, 2020
Assistant Professor Kevin Daniels (ECE/IREAP) and his colleagues, have developed an epitaxial graphene based biosensor that provides rapid detection of COVID-19. 

The biosensor, created by Daniels, Dr. Soaram Kim of the Institute for Research in Electronics and Applied Physics (IREAP), Dr. Heeju Ryu of the Fred Hutchinson Cancer Research Center, Dr. Seo Hyun Kim of the University of Georgia, and Dr. Rachael Myers-Ward of the U.S. Naval Research Laboratory, tested COVID spike protein ranging from one attogram to one microgram, and can detect COVID spike protein in a few seconds, reuse sensors by simply rinsing in sodium chloride (NaCl), and attain results without sending it off to a lab, unlike the current real-time reverse transcription-polymerase chain reaction (RT-PCR) test. Although It is the fastest, most reliable and universally used method for diagnosis, RT-PCR requires a ribonucleic acid (RNA) preparation step, causing a decrease in accuracy as well as sensitivity. In addition, it takes over three hours to complete the current diagnosis for COVID-19. 

The researchers use epitaxial graphene, a single to a few layers of carbon atoms with incredibly high surface area, high electronic conductivity and carrier mobility resulting in ultimate sensitivity for biological sensors. SARS-CoV-2 spike protein antibody & antigen allows high selectivity and an experimental environment that is not dangerous. Therefore the antibody/graphene heterostructure can synergistically improve sensitivity and provide ultra-fast detection.

“These graphene-based sensors are not only much faster than PCR and Rapid test for detecting COVID, but are orders of magnitude more sensitive with the possibility of detecting the virus sooner post-exposure," says Daniels. "The ability to rapidly detect the virus in individuals, even those who were exposed too recently to be detected by other means, is the goal.”

Tags:  Biosensor  COVID-19  Fred Hutchinson Cancer Research Center  Graphene  Healthcare  Heeju Ryu  Institute for Research in Electronics and Applied   Kevin Daniels  Rachael Myers-Ward  Seo Hyun Kim  Soaram Kim  U.S. Naval Research Laboratory  University of Georgia 

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NETL CHEMIST: LAB’S LOW-COST GRAPHENE TO FUEL ‘REBIRTH’ FOR COAL

Posted By Graphene Council, Wednesday, August 26, 2020
In his long career at NETL, McMahan Gray has experienced more than a few successes.

For example, the award-winning research chemist has made valuable contributions to remove carbon from industrial emissions and extract rare earth elements (REEs) from coal byproducts, wastewater and even acid mine drainage.

Another ground-breaking contribution may be just around the corner. As part of an ongoing research effort, Gray serves on an NETL team that’s writing a new chapter in the long productive history of coal that may revolutionize how the mineral is used in the future.

The team has found that rather than combust coal to produce energy, it can be used in new ways to fuel a transformation in carbon-based, high-tech manufacturing to produce safer cars, faster computers, stronger homes, bridges and highways, and even life-saving biosensors to confirm the presence of disease in the human body.

“We were looking for a rebirth in how coal can be used when we began our project,” said Gray, who has worked at the Lab for 34 years. “I think the rebirth we will see is going to produce sophisticated new uses for coal that have absolutely nothing to do with burning it to produce electricity.”

Gray and his NETL colleagues have developed a patent-pending manufacturing process that converts lignite, bituminous and anthracite ranks of coal into graphene, whose superior strength and optical and electrical conductivity properties make it a game-changing material. (Shi, Fan; Matranga, Christopher; Gray, McMahan; Ji, Tuo., Production of Graphene-structured Products from Coal Using Thermal Molten Salt Process, U.S. Non-provisional Patent No. 16/369,753, 2019).

NETL’s low-cost coal-to-graphene, or C2G, manufacturing process will not only generate a superior material to produce high-value products; it also will create new environmentally friendly uses for one of the nation’s greatest resources — its abundant reserves of coal.

According to Gray, it takes a solid team effort to achieve success. “Teamwork, the leadership of an excellent principal investigation (Matranga) and the outstanding work of my colleagues have enabled us to develop this process so coal can be used in new and innovative ways,” Gray said. 

Discovered in 2004, graphene is only one atomic layer thick, but it’s 100 times stronger than construction steel and 1.6 times more electrically conductive than copper electrical wire. Graphene is a form of carbon. Both graphene and carbon possess the same atoms, but they are arranged in different ways, giving each material its own unique properties. For graphene, those differences produce extraordinary strength.  

However, the high cost of existing supplies of graphene have limited its use. “NETL’s technology reduces the cost of manufacturing graphene by up to tenfold while producing a significantly higher-quality material than what is currently available on the market,” Gray said.

In the future, the team envisions using graphene to build lighter and stronger cars. Gray believes it also can be used to create advanced lightweight body armor for U.S. troops.

Because graphene is one of the lightest, strongest and thinnest materials ever discovered, it makes an ideal additive to improve the mechanical properties and durability of cement and produce battery and electrode materials, 3D printing composites, water- and stain- resistant textiles, catalyst materials and supports, and other items.

NETL also has produced graphene quantum dots — small fluorescent nanoparticles with sheet-like structures — and sent them to the University of Illinois at Urbana-Champaign where they are used to fabricate an advanced type of computer memory chip called a memristor. Recent testing has shown that memristors made with NETL graphene have outperformed those made with conventional materials.

In addition, the project team is collaborating with Ramaco Carbon, a Wyoming-based coal technology company, to take advantage of graphene’s superb electrical conductivity to develop new biosensor products that can quickly confirm the presence of Lyme disease, Zika virus or the amount of medication in a blood sample.

Gray is no stranger to advancing ground-breaking projects.

He led NETL researchers who developed the basic immobilized amine sorbent (BIAS) process to capture carbon dioxide (CO2) from coal-burning power plants. Recognizing that the BIAS approach could do more than capture CO2 from coal combustion, Gray has worked to adapt the technology of sorbents, which are designed to absorb targeted chemical compounds, to remove heavy metals, including lead, from public water supplies and recover valuable rare earth elements (REEs) from acid mine discharges and other sources.

REEs, which are needed to produce high-performance optics and lasers, as well as powerful magnets, superconductors, solar panels and valuable consumers products such as smart phones and computer hard drives, are abundant in nature but are often found in low concentrations and are challenging to extract.

Recently, while working on the coal-to-graphene project, Gray made another exciting discovery that directly benefits his efforts in REE extraction. Gray has found that the water used in the coal-to-graphene process contains REEs in the range of 600 parts per million. “In the field of REE research, that’s a very high extraction rate,” Gray said.

“I call it a ‘double hit,’ which sometimes happens when research on one project produces a positive finding to benefit another project,” said Gray, who received a prestigious R&D 100 award in 2012 for the BIAS technology’s carbon capture application.

Gray is listed as the primary or secondary inventor on 21 patents, and his work has been cited in more than 120 scholarly papers. His other notable honors include the Federal Laboratory Consortium Mid-Atlantic Region Award for Technology Transfer and the Federal Laboratory Consortium National Award for Excellence in Technology Transfer.

He has also received the Hugh Guthrie Award for Innovation as one of NETL’s leading scientists. In 2018, he was awarded a Gold Medal for “Outstanding Contribution to Science (Non-Medical)” from the Federal Executive Board for Excellence in the Government.

The Chemistry Department at the University of Pittsburgh has announced it will present Gray with its 2020 Distinguished Alumni Award for his work advancing innovative technologies while serving as a mentor who has inspired hundreds of students and colleagues.

For Gray, NETL’s revolutionary graphene project rejuvenates coal for high-value uses. “Coal gets a bad rap,” said Gray, who also serves as pastor of Second Baptist Church of Penn Hills near Pittsburgh, Pennsylvania.

“The molecular structure behind coal is amazing. There’s really so much more we can do with coal,” he added.

Tags:  Battery  Biosensor  composites  Energy  Graphene  National Energy Technology Laboratory 

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Certainty in just 15 minutes – researchers develop a graphene oxide-based rapid test to detect infections

Posted By Graphene Council, Tuesday, August 4, 2020
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.

Just one drop of blood for a diagnosis
Researchers at the Fraunhofer IZM in Berlin have been working on the project Graph-POC since April 2018 on a graphene oxide-based sensor platform to rise to precisely these challenges in diagnosing infections. A single drop of blood or saliva is all it takes to perform an accurate analysis. Just a few minutes after the drop is applied to the sensor’s surface, electrical signals convey the test result to the family doctor’s office. This rapid test provides certainty within just 15 minutes to replace the protracted blood work in the lab. It takes the error and guesswork out of diagnosis so the physician can prescribe the appropriate treatment or suitable antibiotics.

The test may also be set up to detect antibodies that are present after a patient has recovered from an infection. Fraunhofer IZM researchers are now focusing on this application to detect earlier infections with the COVID-19 virus, which can help with efforts to trace how the infection has spread. The human body forms molecules or proteins called biomarkers in response to an infection. Capture molecules placed on the surface of the graphene-based sensor to detect these biomarkers. Differential measurements of biomarkers’ concentration determine if an infection is present.

3D structure to enlarge the measuring surface
This sensor platform’s most remarkable feature is its base material: Electrically conductive and biocompatible, graphene oxide is also a very reliable means of detection. To date, it has only been used in microelectronics in its original form, a 2D monolayer. Fraunhofer IZM researchers are now applying it in a 3D structure in form of flakes. This 3D form increases the measuring surface and the accuracy of measurements.

Manuel Bäuscher, scientist at Fraunhofer IZM and sub-project manager at Graph-POC, sees great prospects ahead for these graphene oxide sensors: “We can pivot from the current medical field to also develop in the direction of the point of need; that is, towards environmental technology and the detection of environmental impacts. But of course the corona application is our first priority.” The graphene oxide flakes’  3D array and heightened sensitivity also open the door to further applications. For example, it could detect harmful gases such as carbon monoxide or acetone even at room temperature. As it stands, these gases have to first be heated to trigger a surface reaction that today’s sensors can detect. The graphene oxide sensor reacts at lower temperatures when metal oxides bond with its sensitive surface.

Fraunhofer IZM researchers are taking on another challenge to scale the production process up for mass manufacturing: They are looking to apply the graphene oxide coating at the wafer level so that hundreds of chips can be processed at once.

Antibodies detectable after coronavirus infections in about one year
The graphene oxide-based sensors have to be integrated into a plastic carrier and the reliability of the system have to be tested before the rapid tests can be deployed. Although the original project to detect infections is slated to run until spring 2021, the researchers do not expect to be able to verify the sensor for the coronavirus for another year yet. The partners in this project are the Charité, Aptarion Biotech AG, Technische Universität Berlin, MicroDiscovery GmbH and alpha-board GmbH. It is funded by the German Federal Ministry of Education and Research (BMBF).

Tags:  Biosensor  Fraunhofer IZM  Graphene  Healthcare  Manuel Bäuscher 

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Researchers print, tune graphene sensors to monitor food freshness, safety

Posted By Graphene Council, Friday, June 26, 2020
Researchers dipped their new, printed sensors into tuna broth and watched the readings. It turned out the sensors – 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 – can detect histamine down to 3.41 parts per million.

The U.S. Food and Drug Administration has set histamine guidelines of 50 parts per million in fish, making the sensors more than sensitive enough to track food freshness and safety.

Making the sensor technology possible is graphene, a supermaterial that’s a carbon honeycomb just an atom thick and known for its strength, electrical conductivity, flexibility and biocompatibility. Making graphene practical on a disposable food-safety sensor is a low-cost, aerosol-jet-printing technology that’s precise enough to create the high-resolution electrodes necessary for electrochemical sensors to detect small molecules such as histamine.

“This fine resolution is important,” said Jonathan Claussen, an associate professor of mechanical engineering at Iowa State University and one of the leaders of the research project. “The closer we can print these electrode fingers, in general, the higher the sensitivity of these biosensors.”

Claussen and the other project leaders – Carmen Gomes, an associate professor of mechanical engineering at Iowa State; and Mark Hersam, the Walter P. Murphy Professor of Materials Science and Engineering at Northwestern University in Evanston, Illinois – have recently reported their sensor discovery in a paper published online by the journal 2D Materials. (See sidebar for a full listing of co-authors.)

The National Science Foundation, the U.S. Department of Agriculture, the Air Force Research Laboratory and the National Institute of Standards and Technology have supported the project.

The paper describes how graphene electrodes were aerosol jet printed on a flexible polymer and then converted to histamine sensors by chemically binding histamine antibodies to the graphene. The antibodies specifically bind histamine molecules.

The histamine blocks electron transfer and increases electrical resistance, Gomes said. That change in resistance can be measured and recorded by the sensor.

“This histamine sensor is not only for fish,” Gomes said. “Bacteria in food produce histamine. So it can be a good indicator of the shelf life of food.”

The researchers believe the concept will work to detect other kinds of molecules, too.

“Beyond the histamine case study presented here, the (aerosol jet printing) and functionalization process can likely be generalized to a diverse range of sensing applications including environmental toxin detection, foodborne pathogen detection, wearable health monitoring, and health diagnostics,” they wrote in their research paper.

For example, by switching the antibodies bonded to the printed sensors, they could detect salmonella bacteria, or cancers or animal diseases such as avian influenza, the researchers wrote.

Claussen, Hersam and other collaborators (see sidebar) have demonstrated broader application of the technology by modifying the aerosol-jet-printed sensors to detect cytokines, or markers of inflammation. The sensors, as reported in a recent paper published by ACS Applied Materials & Interfaces, can monitor immune system function in cattle and detect deadly and contagious paratuberculosis at early stages.

Claussen, who has been working with printed graphene for years, said the sensors have another characteristic that makes them very useful: They don’t cost a lot of money and can be scaled up for mass production.

“Any food sensor has to be really cheap,” Gomes said. “You have to test a lot of food samples and you can’t add a lot of cost.”

Claussen and Gomes know something about the food industry and how it tests for food safety. Claussen is chief scientific officer and Gomes is chief research officer for NanoSpy Inc., a startup company based in the Iowa State University Research Park that sells biosensors to food processing companies.

They said the company is in the process of licensing this new histamine and cytokine sensor technology.

It, after all, is what they’re looking for in a commercial sensor. “This,” Claussen said, “is a cheap, scalable, biosensor platform.”

Tags:  3D Printing  Biosensor  Carmen Gomes  Graphene  Iowa State University  Jonathan Claussen  Mark Hersam  Northwestern University  Sensors 

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Aerosol-printed graphene unveiled as low cost, faster food toxin sensor

Posted By Graphene Council, Wednesday, June 10, 2020
Researchers in the USA have developed a graphene-based electrochemical sensor capable of detecting histamines (allergens) and toxins in food much faster than standard laboratory tests.

The team used aerosol-jet printing to create the sensor. The ability to change the pattern geometry on demand through software control allowed rapid prototyping and efficient optimization of the sensor layout.

Commenting on the findings, which are published today in the IOP Publishing journal 2D Materials, senior author Professor Mark Hersam, from Northwestern University, said: "We developed an aerosol-jet printable graphene ink to enable efficient exploration of different device designs, which was critical to optimizing the sensor response."

As an additive manufacturing method that only deposits material where it is needed and therefore minimizes waste, aerosol-jet-printed sensors are low-cost, straightforward to make, and portable. This could potentially enable their use in places where continuous on-site monitoring of food samples is needed to determine and maintain the quality of products, as well as other applications.

Senior author Professor Carmen Gomes, from Iowa State University, said: "Aerosol-jet printing was fundamental to the development of this sensor. Carbon nanomaterials like graphene have unique material properties such as high electrical conductivity, surface area, and biocompatibility that can significantly improve the performance of electrochemical sensors.

"But, since in-field electrochemical sensors are typically disposable, they need materials that are amenable to low-cost, high-throughput, and scalable manufacturing. Aerosol-jet printing gave us this."

The team created high-resolution interdigitated electrodes (IDEs) on flexible substrates, which they converted into histamine sensors by covalently linking monoclonal antibodies to oxygen moieties created on the graphene surface by a CO2 thermal annealing process.

They then tested the sensors in both a buffering solution (PBS) and fish broth, to see how effective they were at detecting histamines.

Co-author Kshama Parate, from Iowa State University, said: "We found the graphene biosensor could detect histamine in PBS and fish broth over toxicologically-relevant ranges of 6.25 to 100 parts per million (ppm) and 6.25 to 200 ppm, respectively, with similar detection limits of 2.52 ppm and 3.41 ppm, respectively. These sensor results are significant, as histamine levels over 50 ppm in fish can cause adverse health effects including severe allergic reactions - for example, scombroid food poisoning.

"Notably, the sensors also showed a quick response time of 33 minutes, without the need for pre-labelling and pre-treatment of the fish sample. This is a good deal faster than the equivalent laboratory tests."

The researchers also found the biosensor's sensitivity was not significantly affected by the non-specific adsorption of large protein molecules commonly found in food samples and used as blocking agents.

Senior author Dr Jonathan Claussen, from Iowa State University, said: "This type of biosensor could be used in food processing facilities, import and export ports, and supermarkets where continuous on-site monitoring of food samples is needed. This on-site testing will eliminate the need to send food samples for laboratory testing, which requires additional handling steps, increases time and cost to histamine analysis, and consequently increases the risk of foodborne illnesses and food wastage.

"It could also likely be used in other biosensing applications where rapid monitoring of target molecules is needed, as the sample pre-treatment is eliminated using the developed immunosensing protocol. Apart from sensing small allergen molecules such as histamine, it could be used to detect various targets such as cells and protein biomarkers. By switching the antibody immobilized on the sensor platform to one that is specific towards the detection of suitable biological target species, the sensor can further cater to specific applications. Examples include food pathogens (Salmonella spp.), fatal human diseases (cancer, HIV) or animal or plant diseases (avian influenza, Citrus tristeza)."

Tags:  Biosensor  Carmen Gomes  Graphene  Iowa State University  Jonathan Claussen  Kshama Parate  Mark Hersam  Northwestern University  Sensors 

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Crumpled graphene makes ultra-sensitive cancer DNA detector

Posted By Graphene Council, Friday, March 27, 2020
Graphene-based biosensors could usher in an era of liquid biopsy, detecting DNA cancer markers circulating in a patient’s blood or serum. But current designs need a lot of DNA. In a new study, crumpling graphene makes it more than ten thousand times more sensitive to DNA by creating electrical “hot spots,” researchers at the University of Illinois at Urbana-Champaign found.

Crumpled graphene could be used in a wide array of biosensing applications for rapid diagnosis, the researchers said. They published their results in the journal Nature Communications.

“This sensor can detect ultra-low concentrations of molecules that are markers of disease, which is important for early diagnosis,” said study leader Rashid Bashir, a professor of bioengineering and the dean of the Grainger College of Engineering at Illinois. “It’s very sensitive, it’s low-cost, it’s easy to use, and it’s using graphene in a new way.”

While the idea of looking for telltale cancer sequences in nucleic acids, such as DNA or its cousin RNA, isn’t new, this is the first electronic sensor to detect very small amounts, such as might be found in a patient’s serum, without additional processing.

“When you have cancer, certain sequences are overexpressed. But rather than sequencing someone’s DNA, which takes a lot of time and money, we can detect those specific segments that are cancer biomarkers in DNA and RNA that are secreted from the tumors into the blood,” said Michael Hwang, the first author of the study and a postdoctoral researcher in the Holonyak Micro and Nanotechnology Lab at Illinois.  

Graphene – a flat sheet of carbon one atom thick – is a popular, low-cost material for electronic sensors. However, nucleic-acid sensors developed so far require a process called amplification – isolating a DNA or RNA fragment and copying it many times in a test tube. This process is lengthy and can introduce errors. So Bashir’s group set out to increase graphene’s sensing power to the point of being able to test a sample without first amplifying the DNA.

Many other approaches to boosting graphene’s electronic properties have involved carefully crafted nanoscale structures. Rather than fabricate special structures, the Illinois group simply stretched out a thin sheet of plastic, laid the graphene on top of it, then released the tension in the plastic, causing the graphene to scrunch up and form a crumpled surface.

They tested the crumpled graphene’s ability to sense DNA and a cancer-related microRNA in both a buffer solution and in undiluted human serum, and saw the performance improve tens of thousands of times over flat graphene.

“This is the highest sensitivity ever reported for electrical detection of a biomolecule. Before, we would need tens of thousands of molecules in a sample to detect it. With this device, we could detect a signal with only a few molecules,” Hwang said. “I expected to see some improvement in sensitivity, but not like this.”

To determine the reason for this boost in sensing power, mechanical science and engineering professor Narayana Aluru and his research group used detailed computer simulations to study the crumpled graphene’s electrical properties and how DNA physically interacted with the sensor’s surface.

They found that the cavities served as electrical hotspots, acting as a trap to attract and hold the DNA and RNA molecules.

“When you crumple graphene and create these concave regions, the DNA molecule fits into the curves and cavities on the surface, so more of the molecule interacts with the graphene and we can detect it,” said graduate student Mohammad Heiranian, a co-first author of the study. “But when you have a flat surface, other ions in the solution like the surface more than the DNA, so the DNA does not interact much with the graphene and we cannot detect it.”

In addition, crumpling the graphene created a strain in the material that changed its electrical properties, inducing a bandgap – an energy barrier that electrons must overcome to flow through the material – that made it more sensitive to the electrical charges on the DNA and RNA molecules.

“This bandgap potential shows that crumpled graphene could be used for other applications as well, such as nano circuits, diodes or flexible electronics,” said Amir Taqieddin, a graduate student and coauthor of the paper.

Even though DNA was used in the first demonstration of crumpled graphene’s sensitivity for biological molecules, the new sensor could be tuned to detect a wide variety of target biomarkers. Bashir’s group is testing crumpled graphene in sensors for proteins and small molecules as well.

“Eventually the goal would be to build cartridges for a handheld device that would detect target molecules in a few drops of blood, for example, in the way that blood sugar is monitored,” Bashir said. “The vision is to have measurements quickly and in a portable format.”

Tags:  Biosensor  Graphene  Healthcare  Mohammad Heiranian  Narayana Aluru  Rashid Bashir  Sensors  University of Illinois at Urbana-Champaign 

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Grolltex Graphene Closes Oversubscribed Private Placement Financing Round

Posted By Graphene Council, Wednesday, September 11, 2019
Updated: Tuesday, September 10, 2019

Grolltex (named for ‘graphene-rolling-technologies’) is the largest commercial producer of single layer, ‘electronics grade’ graphene and graphene sensing materials in the U.S. They have announced that it has closed a non-brokered, oversubscribed private placement financing, in the form of a convertible note, with local area private investors. 

The gross proceeds of the private placement will be used for general working capital purposes and for increasing the capacity and quality testing capabilities of the company’s production facility in San Diego, California.


The company is focused on delivering inexpensive and enabling solutions to advanced nano-device and graphene sensor makers by fabricating the highest quality single layer graphene attainable, via chemical vapor deposition (or ‘CVD’).

The company is now capable of producing monolayer graphene sensors on large area plastic sheets at a cost of pennies per unit, in a high throughput and sustainable way.  Further, Grolltex is helping customers that currently produce their graphene sensors on silicon wafers, to transition that production capacity to making their sensors on large area sheets of biodegradable plastic instead, at a >100X cost savings. 

Monolayer graphene films are today seen as the most promising futuristic sensing materials for their combination of surface to volume ratio (the film is only one atom thick) and conductivity (the most conductive substance known at room temperature). Markets that are commercializing advanced sensors made of graphene include DNA sensing and editing, new drug discovery and wearable bio-monitors for glucose sensing and autonomous blood pressure monitoring via patches or watch-like wearable bracelet devices.

No securities were issued and no cash was paid as bonuses, finders’ fees, compensation or commissions in connection with the private placement.

Tags:  Biosensor  CVD  Graphene  Groltex  Sensors 

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Cardea Bio Announces New Partnership with Nanosens Innovations

Posted By Graphene Council, Friday, April 5, 2019
Updated: Thursday, April 4, 2019
Cardea Bio, leading manufacturer of commercial-quality graphene digital biosensors, together with Nanosens Innovations, introduces the new CRISPR-Chip which has the potential to detect genetic mutations within minutes. The relationship with Nanosens falls under Cardea's Innovation Partnership Program, which enables Nanosens to build breakthrough science on top of Cardea's IP-protected graphene biosensors.

The co-developed CRISPR-Chip is the first unamplified label-free nucleic acid testing device. Details about its development can be found in the recently published Nature Biomedical Engineering paper, "Detection of Unamplified Target Genes via CRISPR/Cas9 Immobilized on a Graphene Field-Effect Transistor," from the Keck Graduate Institute at Claremont College.

CRISPR-Chip inventor and corresponding author Dr. Kiana Aran explains, "I first considered using CRISPR-Cas9 on a digital biosensor as a DNA search engine while I was at UC Berkeley. At Keck, I attempted to design and develop the biosensors myself, but it was difficult to construct them with the consistency and quality needed for this research. When I understood that a partnership with Cardea was possible, where the company's patented, commercial-grade, high-volume graphene biosensors could be used in place of building my own, it cut months to years out of my research."

CRISPR-Chip is a hand-held device that combines thousands of CRISPR molecules with Cardea's graphene transistor. The device scans though applied DNA to find specific genes or mutations. The transistor is extremely sensitive to electrically charged materials, like DNA. If the specified DNA is found, it binds to the surface, creating an additional charge which is sensed by the device.

"In its current format, CRISPR-Chip can be used to help researchers design better CRISPR complexes for gene editing," continues Dr. Aran. "With CRISPR-Chip, the complexes can be tested faster than ever before."

Tags:  Biosensor  Cardea Bio  DNA  Graphene  Keck Graduate Institute at Claremont College  Kiana Aran  Nanosens Innovations 

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