In the coming months, up to 25% of global vaccines will be wasted. We can solve that with creating a simple microtextured surface.
The coronavirus vaccine expires fast. The slightest rise in temperature can render a dose ineffective, meaning one less in someone’s arm and one more in the trash. But perhaps there’s a solution, and it lies in tweaking the physical pattern of the nano-sized lipid packaging.
Conventional vaccines vs the COVID-19 vaccine.
Compared to history’s other vaccines, the COVID-19 one is unique. Yes, it’s still a vaccine which gives you immunity, but main reason why it differs compared to conventional vaccines is because it uses messenger RNA (mRNA).
This is why it’s true when people say “you cant get sick from the vaccine, because it doesn’t actually give you the virus.” Because it doesn’t. With past vaccines they would inject a weakened/dead version of the virus causing a stimulated immune response. On the other hand, the mRNA vaccine is not the virus itself but simply a copy of instructions that teaches your cells to make virus proteins. These virus proteins produced are not actually the virus, but more like harmless snippets of its body which are just enough to trigger your immune system in the same way when presented.
And this is also why the vaccine had come out so fast. Most conventional vaccines were made from viruses grown in chicken eggs or mammalian cells. The process of collecting the viruses, and adapting them to grow in the lab is time consuming and complex. And this doesn’t even include the countless rounds of testing. In fact, the fastest vaccine developed prior to COVID was the mumps vaccine — which took 4 long years.
In a global pandemic, people knew they couldn’t use the same method as these steps would greatly slow down development. But with mRNA vaccines, you can skip this tedious growing process — the RNA is made from a DNA template in the lab, which can be synthesized from an electronic sequence and sent using a computer across the world in a blink. So compared to four years, this gave vaccine companies a huge hand in helping them reach success in a quarter of the time.
So far, coronavirus vaccination has shown extreme success. The Pfizer vaccine has an efficacy of 95% and the Moderna one just slightly under. The fact that it’s this accurate and fast makes it seem like humanity has hit a jackpot.
But things are too good to be true.
The vaccines need to be kept at levels colder than Antarctica.
This coronavirus vaccine expires super fast and that’s because the main component of the virus, the mRNA, is incredibly delicate.
mRNA is vulnerable out in the environment as there are always enzymes and water moisture in the air which can destroy it in a matter of hours. This means that the coronavirus vaccine is extremely sensitive to warm temperatures — the higher the temperature, the more water the air can hold as moisture.
While there’s nothing we can do to permanently halt these water molecules from breaking the bonds of the mRNA, we can use extremely cold temperatures to slow this procedure and reduce the amount of lingering water vapour, giving us extra time to get them into people’s bodies. This is why freezing food makes it last longer — the bacteria and enzymes which make it go bad are slowed down.
The Pfizer vaccine will expire if they can’t be kept at -70 degrees C and after thawed, can only last for 5 days at a standard refrigerator temperature. The Modern vaccine is slightly more durable in that only only has to reach -20 C and will last 30 days after thawed in a normal fridge. But in comparison, other vaccines like the flu vaccine only need to be stored at a consistent level of 2 to 8 degrees C.
So yes, while we may have a massive breakthrough in speed and accuracy, the effort to vaccinate an upwards of 8 billion people, 36% living in poverty, while keeping those temperatures low will be challenging.
25% of global vaccines will be lost in transit and roughly 10% of the Pfizer vaccine will be rendered ineffective.
A specialized freezer that can reach the temperature requirements of the Pfizer vaccine costs roughly $5000 each. Even a typical deep freezer can cost up to $500. And that doesn’t account for the massive power consumption. It’s already difficult for many parts of the U.S. and Europe to secure this technology so implementing this equipment in rural areas with no electricity or clean water is certainly not possible.
To make matters worse, the world is also suffering from a shortage of dry ice. Thousands of shipments are being made on a daily basis where vaccines are packaged in pools of dry ice to the point where the cold supply chain cannot keep up. Additionally, these boxes of dry ice can only be opened up twice a day, because the coldness eventually wears out after 24 hours, leaving much room for human error.
How we’re currently tackling this issue.
There’s two ways we’re trying to go about this problem: to reform vaccine fridges, and coating the mRNA with a lipid nanoparticle coating.
Arktek — A.K.A. “Super thermos”
Developed by the humanitarian inventors at the Bill and Gates-funded Global Health labs, this is a high-tech insulated cylinder which can keep things cold for up to a week at a time relying on no external power source. This innovation would make it possible for them to bring the vaccine to villages where there is no electricity, no deep freezer — not any freezer — and keep it at the required temperature.
Of course, they had to use a different method than just keeping dry ice more cold or finding a different method of converting electricity into such a low temperature output. Instead, they use an alcohol-based phase change material (PCM), which is just a more durable form of ice, and water-based salt solution packs.
This was how the Ebola vaccine distribution was a success. Through reforming their ice, they made it so then there was no need for a replacement for several days and the compartment didn’t need electricity. The Artkeks were also small enough to be carrying on motor bikes, each one capable of holding up to 500 vials (each vial containing 6 doses). Thus, it made it much easier for vaccinators to travel to rural areas and ensure everyone got effective vaccines.
The Ebola had to be stored at -60 C which is already very difficult, but now we need to consider creating devices that can do the same but at -80 C. We also need to consider that unlike Ebola, which was contained to one specific region, the coronavirus is a global pandemic. We’re no longer distributing to one specific area — it’s the entire world now and it will be questionable to see if the Arktek will be able to keep up.
A lipid coating
On the other hand, this involves the nano layer of packaging. Vaccine developers are also trying to see what layers of protection they can add at the nanoscale, because after all, the destruction involving enzymes and water molecules with the mRNA are all happening at a level we can’t see.
The current coronavirus vaccine has a lipid nanoparticle coating around the delicate mRNA. Lipids are hydrophobic because they have non-polar bonds, and thus repel surrounding water molecules which have polar bonds. This is very similar to how oil cannot mix with water — because oil is a non-polar substance.
The difference in the strength of the Pfizer vaccine and the Moderna vaccine is the slightly stronger lipid nanoparticle coating in the Moderna vaccine. This allows it to remain in good condition for an extra 25 days compared to Pfizer’s in a standard fridge after thawed.
A SARS-CoV-2 particle has a very similar lipid outer layer to protect its precious genetic material. But if it is left alone outside, it only has a couple of hours before its genetic material will be twisted up and completely ruined due to the harmful air moisture. Similarly, the coating around the mRNA in the vaccine doesn’t last for a long time which is why these specialized freezers are still needed to slow the process of water molecules from coming into contact with the mRNA.
This isn’t enough.
It’s clear we have a shortage of special fridges, but even considering we did have enough, there would always be human error that would lead to huge losses of batches because of how the mRNA can be completely broken even with the slightest temperatures changes. And once vaccines are thawed, there’s nothing we can do to help slow the expiry date, even with the best of the best freezers.
Vaccine waste is caused in the first place because mRNA is so fragile. So the only way of getting the best shot at reducing this waste is to further develop the resistance of the mRNA’s capsule lipid layer to outside water moisture. Yes, that means making it superhydrophobic.
I actually considered adding fats upon more layers of fats as a potential solution but eventually I realized while this would certainly create a stronger barrier between the mRNA and outer water molecules, the casing would still wear out pretty fast and so this wouldn’t actually be the best way to solve this problem. And I thought there must be better ways at increasing a surface’s hydrophobia rather than just adding extra layers.
So I though, what if we could design an outer layer that’s not only superhydrophobic but actually can’t degrade at all?
Understanding what makes things hydrophobic.
In attempt to realize how to make things more hydrophobic, we first need to break down what actually makes something hydrophobic. Hydrophobic surfaces repel water but that’s the only thing which most people know.
What makes a thing “wet”?
When a water droplet comes in contact with a surface, the shape of the droplet may change depending on the nature of the surface. What makes something wet in nature is very simple:
- The more the water spreads on the surface, the more “wet” it is
- The amount it spreads out is affected by the angle between the surface and tangent of the water’s surface — the contact angle
- A smaller contact angle than 90 degrees implies that water tends to spread out more thinly on the surface
- If the contact angle is greater than 90 degrees, the water clusters together and does not spread on the surface, thus the surface does not get “wet”
“Hydro” means water and “phobos” means fear in Greek. A material is said to be hydrophobic if it does not like water, or depending on the point of view, the water does not like it.
Water molecules are naturally attracted to each other through the positive and negative charges of the hydrogen and oxygen and so will stay close together and as far away as possible from the hydrophobic surface. Because of this, water molecules tend to cluster together to form round droplets on a hydrophobic surface, repelling the liquid, but will spread apart on a hydrophilic (water-loving) surface as they are more attracted to the surface rather than to each other.
Making something more or less hydrophobic is a physical effect.
The solution to unlocking the powers of superhydrophobia is as simple as adding micro bumps onto a flat hydrophobic surface. Ultimately, these bumps can help to create large contact angles.
The connection between the material and the water is reduced by the bumpy surface and because water molecules are attracted to each other more than they are to the surface, the water droplets become even more spherical in shape. This makes it extremely easy for them to roll off the surface.
So now it’s not just the molecular interactions between polar and non-polar substances but its about changing the physical texture of the already hydrophobic area so the water molecules cannot spread themselves out what so ever.
Looking at the Lotus leaf — biomimicry
Yes the plant. Its leaves are covered in a form of wax, which is already a non-polar substance and will repel the polar bonds of the water molecules. But things don’t stop there.
Lotus leaves are known to be superhydrophobic because of how they additionally posses this bumpy texture. As a result, water does not adhere well to lotus leaves, allowing droplets to attract “into” themselves, which pulls them into near perfect spheres. This makes it very hard for the water to have contact with its surface and spread itself out thinly.
If you were to put a drop of water onto a Lotus leaf, you would see a water sphere lying loosely on top so that even the tiniest movements would cause them to roll off, taking dirt particles away (causing it to be self-cleaning as well). In fact, depending on the angle which the water hits and the amount, they might bounce right back.
Bumpy surfaces are extremely durable
They can be up to a quadruple time more long-lasting than a typical flat hydrophobic surface. Because the bumps make it more challenging for the water to actually come in contact with the material, it takes much longer for the superhydrophobicity to wear off.
It’s like how an umbrella that’s constantly battered by the rain is more likely to wear out faster than if you only used it in sunny weather.
And it’s a physical pattern which is engraved on the surface, which makes it very difficult for any drastic alterations to occur v.s. if there was no physical structure.
Applying bumps to the lipid mRNA coating.
Vaccine developers have already designed the mRNA lipid nanoparticle coating to be non-polar, like the waxy coating on the Lotus leaves. This property will already repel the water molecules for a period of time.
But obviously, the resistance isn’t enough. And the simple solution lies in adding bumps to the surface to ensure there’s a greater contact angle, essentially lowering the chances of the layer from getting “wet” and easier to degrade. Ultimately, changing the physical texture of the lipid coating can cause the mRNA to have a much more proactive outer casing, extending its expiry date.
Moreover, because the bumpy surface creates a self cleaning surface, the water molecules that repel from lipid layer can also help to clear away enzymes lurking on the surface and could eventually reach the mRNA.
So in case there is human error in transportation or there are accidental temperatures changes, it won’t be completely hopeless that we’ll have to throw out batches of vaccines. And after thawing, even if this can allow the shelf life to be extended by a few days or even a few hours, that gives us more time to get vaccines into people’s arms rather than tossing them into the trash at the end of the day.
But of course there are still challenges.
While the idea is there, we still don’t have the technology to create detailed textured surfaces at the nanoscale that can meet global demands.
- We would need to figure out a new method of self-assembly which would require extensive time and research.
- We could turn towards 3D printing technology, but society has not yet reached a point when it is lightening fast and extremely cheap/accessible — MIT has applied these bumpy properties to make metal more hydrophobic but the technology can cost up to $100,000 each and it takes 4 hours to carve the texture onto a material the size of a card.
- The pattern would need to be engraved on a surface the size of a singular virus particle. That’s so tiny it’s unfathomable. Nonetheless, we don’t even know if current technology is able to reach sizes this small in time to help this pandemic.
It’s all in the texture.
Admist a global pandemic, vaccines are by far one of the most precious resources we have to end the outbreak. It’s sad to witness so many go to trash all because of their fragility.
The solution to developing ultra-resistance vaccines isn’t only about building better special freezers, it’s about changing the inner protective lipid coating to be stronger and more capable of handling water moisture. And that doesn’t mean adding more chemicals or fat layers, nor using complex artificial nanotechnology capsules. It can really be as simple as changing the physical texture of the outer layer and leaving the rest to the beauty of chemistry.
Hi, it’s Ashley. Thanks so much for taking the time to read this article, it really does mean a lot to me :)
In the meantime I would love to connect with you! As always, trying to meet new people and learn as much as possible.