Researchers have reviewed different types of nanomaterials and how they can be used for the detection, prevention, and treatment of coronavirus disease 2019 (COVID-19).
A variety of different strategies have been tested or are under development for combating the COVID-19 pandemic. Several types of nanomaterials have also been tested for treatment and diagnosis. Many vaccines currently deployed also use nanomaterials in their composition. In a recent review paper, published in the Sustainable Cities and Society, authors reviewed the different types of nanomaterials and their uses in combating the pandemic.
Many materials have been made into nanometer size. They include carbon materials, metals, inorganic, and polymeric materials. Carbon nanomaterials include graphene, graphene oxide, carbon nanotubes, and fullerenes. These materials have good sensing and antimicrobial properties, which can be used for COVID-19 applications.
Carbon nanomaterials
Graphene-based field-effect transistors have been used to analyze COVID-19 viral loads in samples. Studies have shown highly sensitive and fast detection of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) – the causative pathogen of COVID-19 – without any sample pretreatment. Graphene oxide has also been used as an antiviral agent. Graphene and graphene oxide have been used in face masks to inactivate viruses and allow mask reuse.
Another useful carbon nanomaterial is carbon nanotubes. They have several useful properties like high surface area, good biocompatibility, and easy chemical functionalization. They have been tested in virus detection, virus inactivation, use in face masks, including their use in microfluidic devices using carbon nanotube arrays for virus detection. However, these materials can interact with DNA in animals, so their use in vivo is still questionable.
Metal and metal-based nanoparticles
Many types of metal and metal-based nanoparticles have been used for combating viruses. Gold nanoparticles are one of the most studied such materials. Studies have shown a gold nanoparticle-sialic acid composite can prevent virus attachment to host cells. Several sensors using gold nanoparticles have been used to identify disease cells and for DNA amplification, and these techniques could also be used for detecting SARS-CoV-2.
Copper is known to inactivate viruses. Several studies have reported the antimicrobial activity of copper nanoparticles, which could be used for making personal protective equipment, for example. SARS-CoV-2 has also been found to be deactivated on copper surfaces faster than other surfaces.
Another metal known for its antimicrobial activity is silver. Silver nanoparticles have been reported to inhibit several viruses like monkeypox, HIV-1, HSV, and others. Zn is another metal that has been reported to help in COVID-19, with studies suggesting chloroquine could act as a zinc ionophore. Increasing the concentration of Zn in cells is thought to help better combat COVID-19.
Iron oxide nanoparticles have been used to cure anemia, and in vitro studies have shown they also have antiviral properties. Computational analysis has shown iron nanoparticles can bind to the SARS-CoV-2 spike protein. In addition, the magnetic properties of these nanoparticles have been used in biosensors for virus and other pathogen detection. Other metal oxides that may help combat COVID-19 are titanium dioxide, which could help with photocatalytic decontamination of virus-infected surfaces.
Two-dimensional metal carbides and nitrides (MXenes) are another class of emerging materials used to inactivate viruses on face masks, as are metal-organic framework (MOF) materials.
Quantum dots
Quantum dots are generally semiconductor nanoparticles less than about 10 nm in size, having a tunable optical wavelength. Hence, they are used as fluorescent probes and sensors. Carbon quantum dots have been shown to have antiviral properties. In addition, they can be potentially used to inactivate viruses because of their interaction with the spike protein or inhibiting viral replication.
Polymer-based nanoparticles
Both synthetic and natural polymer-based nanomaterials can be used to combat microbial infections. Synthetic polymer nanoparticles such as poly(lactic-co-glycolic) acid are well-known delivery vehicles for delivering drugs or other materials in the body.
Cellulose-based natural polymers are used in many filters and in face masks to filter out virus particles. Nanocellulose materials have also been used in sensors and displays to improve their sensitivity. Chitosan nanoparticles are another natural polymer-based materials widely used as drug carriers and delivery vehicles.
Lipid nanoparticles are another class of materials made of different lipid materials and have been studied as delivery platforms for mRNA-based vaccines, including for COVID-19.
Although several types of nanomaterials are being used or have the potential to be used to combat COVID-19, their toxicity and sustainable use need to be studied further. At the same time, clinical trials have shown that the use of lipid nanoparticles in vaccine technology – such as the novel mRNA platform – is safe and very promising in terms of efficacy. Collecting more information from these trials could pave the way for their use in more complex nanomedicine technologies.
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