closeup of a young businessman, in a gray suit, sitting next to his suitcase in the waiting hall of an airport or a train station, holding a surgical mask in his hand

As a COVID-19 and medical device researcher, I understand the importance of face masks to prevent the spread of the coronavirus. So I am intrigued that some mask manufacturers have begun adding graphene coatings to their face masks to inactivate the virus. Many viruses, fungi and bacteria are incapacitated by graphene in laboratory studies, including feline coronavirus.

Comprendiamolo

Because SARS CoV-2, the coronavirus that causes COVID-19, can survive on the outer surface of a face mask for days, people who touch the mask and then rub their eyes, nose, or mouth may risk getting COVID-19. So these manufacturers seem to be reasoning that graphene coatings on their reusable and disposable face masks will add some anti-virus protection. But in March, the Quebec provincial government removed these masks from schools and daycare centers after Health Canada, Canada’s national public health agency, warned that inhaling the graphene could lead to asbestos-like lung damage.

Questa mossa è giustificata dai fatti o è una reazione eccessiva? Per rispondere a questa domanda, può essere utile sapere di più su cosa è il grafene, come uccide i microbi, compreso il virus SARS-COV-2, e cosa sanno finora gli scienziati sui potenziali impatti sulla salute della respirazione del grafene.

Grafene

How does graphene damage viruses, bacteria and human cells? Graphene is a thin but strong and conductive two-dimensional sheet of carbon atoms. Leggi qui.

Ci sono tre modi in cui può aiutare a prevenire la diffusione dei microbi:

  • Microscopic graphene particles have sharp edges that mechanically damage viruses and cells as they pass by them.
  • Il grafene è caricato negativamente con elettroni altamente mobili che intrappolano elettrostaticamente e inattivano alcuni virus e cellule.
  • Il grafene fa sì che le cellule generino radicali liberi di ossigeno che possono danneggiarle e compromettere il loro metabolismo cellulare.

Prendete nota

Why graphene may be linked to lung injury. Researchers have been studying the potential negative impacts of inhaling microscopic graphene on mammals. In one 2016 experiment, mice with graphene placed in their lungs experienced localized lung tissue damage, inflammation, formation of granulomas (where the body tries to wall off the graphene), and persistent lung injury, similar to what occurs when humans inhale asbestos. A different study from 2013 found that when human cells were bound to graphene, the cells were damaged. Leggi qui.

In order to mimic human lungs, scientists have developed biological models designed to simulate the impact of high concentration aerosolized graphene – graphene in the form of a fine spray or suspension in air – on industrial workers. One such study published in March 2020 found that a lifetime of industrial exposure to graphene induced inflammation and weakened the simulated lungs’ protective barrier.

It’s important to note that these models are not perfect options for studying the dramatically lower levels of graphene inhaled from a face mask, but researchers have used them in the past to learn more about these sorts of exposures. A study from 2016 found that a small portion of aerosolized graphene nanoparticles could move down a simulated mouth and nose passages and penetrate into the lungs. A 2018 study found that brief exposure to a lower amount of aerosolized graphene did not notably damage lung cells in a model.

Dal mio punto di vista di ricercatore, questo trio di risultati suggerisce che un po' di grafene nei polmoni è probabilmente OK, ma molto è pericoloso.

Although it might seem obvious to compare inhaling graphene to the well-known harms of breathing in asbestos, the two substances behave differently in one key way. The body’s natural system for disposing of foreign particles cannot remove asbestos, which is why long-term exposure to asbestos can lead to the cancer mesothelioma. But in studies using mouse models to measure the impact of high dose lung exposure to graphene, the body’s natural disposal system does remove the graphene, although it occurs very slowly over 30 to 90 days.

The findings of these studies shed light on the possible health impacts of breathing in microscopic graphene in either small or large doses. However, these models don’t reflect the full complexity of human experiences. So the strength of the evidence about either the benefit of wearing a graphene mask, or the harm of inhaling microscopic graphene as a result of wearing it, is very weak.

Rischio teorico

No obvious benefit but theoretical risk. Graphene is an intriguing scientific advance that may speed up the demise of COVID-19 virus particles on a face mask. In exchange for this unknown level of added protection, there is a theoretical risk that breathing through a graphene-coated mask will liberate graphene particles that make it through the other filter layers on the mask and penetrate into the lung. If inhaled, the body may not remove these particles rapidly enough to prevent lung damage.