mRNA Vaccines — Building from a Message (Part 2)

In the late 1970s, a Canadian biochemist named Peter Cullis was studying something called lipids.

So let's understand what is a lipid.

Lipids are a group of molecules that includes fats and oils.

and they are also an important part of every cell in your body.

Every cell is surrounded by a thin membrane and much of that membrane is made from lipids.

But lipids have another interesting property.

Put certain lipids in water and they naturally gather together.

Under the right conditions, they can arrange themselves into a very small shell, a layer of lipids surrounding a tiny space in the middle.

And that gave scientists an idea.

could that tiny lipid shell be used to carry a medicine? Put the medicine in the middle, surround it with lipids and now the medicine has a protective covering around it.

That was something useful for medicines that were fragile and could easily be broken down inside the body.

But making this work reliably was difficult.

Cullis and many other researchers spent years studying different lipids.

which ones worked best, how to combine them and how to use them to protect and deliver medicines into cells.

Over time, this work helped lead to what we now call lipid nanoparticles.

Think of a lipid nanoparticle as a tiny package made from lipids, designed to protect what it carries and help deliver it into a cell.

Lipid nanoparticles are around 100 nanometers across.

Just to give you some perspective, a human hair is tens of thousands of nanometers wide.

Now think back to our problem with mRNA.

mRNA was extremely fragile.

It needed protection from the enzymes that could break it apart.

and it needed a way to get inside a cell.

The lipid nanoparticles could help solve both problems.

Put the mRNA inside this tiny lipid package and the lipids help protect it.

The cell can then take the package in allowing the mRNA to be released inside the cell where its message can finally be read.