Medical masks, filter systems, hydrogel disinfectants, rapid tests for the detection of COVID-19 and other graphene-based devices are undergoing the latest tests or are already on the market. "Rusgrafen.Media" talks about promising developments.
In the context of the coronavirus pandemic, graphene medical applications are developing at an accelerated pace. The combination of unique properties of graphene materials - biocompatibility, chemical stability, impermeability to liquids and gases, high electrical conductivity and antibacterial activity, as well as strength, flexibility and elasticity - allows you to use them to create many useful devices.
At the end of March, the New York-based company LIGC Applications presented the Guardian G-Volt respiratory mask equipped with a filtering system based on laser-induced graphene - microporous electrically conductive foam from interconnected graphene flakes. The mask comes with a portable battery connected via a USB port. It feeds the mask with a small current, due to which the graphene filter material repels even the smallest particles of water and dust that can carry viruses. According to the developers, the Guardian G-Volt is impermeable to 99% of 0.3 micron particles and 80% of smaller ones.
Self-cleaning mask from Guardian G-Volt.
At home, Guardian G-Volt is proposed to be stored on a recharge in a special docking station, where, using resistive heating and the use of a sterilizing solution, the filtration system is thoroughly cleaned. Products have been tested at the Israeli Ben-Gurion University and Rice University in the United States. It is planned to launch production of laser-induced graphene filters and Guardia n G-Volt masks in the near future in Belgium. The cost of one device will be about £ 30.
Protective mask from planarTECH and IDEATI
A promising direction is being developed by researchers from the Hong Kong Polytechnic University. The technology developed by them allows you to apply several layers of graphene to medical masks made of non-polythene polymeric materials, after which the filtering surface of the mask becomes super-hydrophobic - capable of self-cleaning from liquid droplets, virus carriers. You can reuse such a mask after a simple disinfection procedure - you need to hold the mask in direct sunlight for 40-100 seconds.
The Italian company Directa Plus proposed the use of graphene materials to create, in addition to medical masks, more reliable gloves and gowns designed specifically for medical personnel fighting the coronavirus. Another European company, Graphenea, has launched the production of an alcohol-based disinfectant graphene hydrogel and distributes it free of charge to doctors, police, military and the elderly.
The antimicrobial, filtering and electrically conductive properties of graphene are also used to create promising air purification systems for office centers and industrial storage facilities. The R&D department of the American graphene company G6 Materials (formerly Graphene 3D Lab), founded by MIPT graduates Elena Polyakova and Daniil Stolyarov, is actively working in this direction.
The creation of hypersensitive biosensors based on graphene is one of the most dynamic developing areas of graphene technology. Prototypes of devices capable of detecting the DNA of individual cancer cells, measuring toxins, tracking the content of immunoglobulins and glucose levels have already been presented. The most important task today has been the development of effective test systems for the diagnosis of coronavirus infection COVID-19, which causes the SARS-CoV-2 virus.
Most of the current COVID-19 tests are based on the reverse transcription polymerase chain reaction (PCR) method, which analyzes the genetic material of the virus. Together with the preparation of the test material, PCR diagnostics can take from several hours to two days, which in a pandemic is an extremely long time. Scientists from the Korea Institute of Basic Sciences and other research organizations of the Republic of Korea have developed a biosensor capable of detecting the SARS-CoV-2 virus in a minute.
The principle of action of graphene biosensor (Giwan Seo et al. ACS Nano, 2020).
The biosensor is a field effect transistor based on a high quality graphene sheet with high electrical conductivity. Antibodies specific to the spike SARS-CoV-2 proteins, the spiky outgrowths on the surface of the virus, are attached to the surface of graphene. The interaction of SARS-CoV-2 with antibodies leads to a change in the strength of the electric current through the transistor, which is easily detected by measuring equipment.
A team of Korean scientists tested the technique using swabs from the nasopharynx of coronovirus-infected and healthy patients. Diagnostic time averaged a minute. However, the sensitivity of the new test was 2-4 times less than that of PCR diagnostic systems. Scientists continue to work to improve the sensitivity of the graphene biosensor.
A similar direction is being developed by the American company Grolltex. According to company management, they managed to develop an inexpensive and effective graphene biosensor on a plastic substrate that can detect 12 different viruses at the same time, including SARS-CoV-2. At the moment, the company is looking for partners to launch mass production of graphene biosensors.
Graphene particles have a large surface area and high absorption properties, and therefore they can be used to create filters. But is it worth it? The same activated carbon, which is several times cheaper than graphene, shows not the worst, but even the best absorption activity. Therefore, what feasibility primarily drives the creators of graphene masks - constructive or marketing - is a good question!
Another thing is graphene oxide, that is, graphene containing oxygen-containing groups in its plane and along the edges. There are many scientific publications on the high antibacterial, antiviral and even fungicidal activity of graphene oxide. In addition, it is biocompatible. Graphene oxide is likely to soon displace much more expensive and less effective silver microparticles, which are so often added to various antiseptics. The development of promising disinfectants and coatings based on graphene oxide is actively engaged in by our partners, the company Grafenox, under the leadership of a senior researcher at the Institute of Problems of Chemical Physics of the Russian Academy of Sciences, Sergei Baskakov.