Hi listeners, Benjamin here. It's a holiday week for a lot of folk in the UK, but that won't stop the nature podcast.

Now, the Artemis II mission is still going on. The crew are on their way back from the moon as we're recording this.

We're hoping to have a special report on the mission later in the week. But for this episode, I've assembled an all-star team to talk about a few stories we've read about in the Nature Briefing. One of them is Lizzie Gibney. Lizzie, thank you for being here today. Hello, Ben. Good to be here. Thank you very much. And the other is Nature Briefing's Flora Graham. Flora, how are you doing today? Really, really well. Thank you so much. Good stuff. Well, listen, three stories today. Why don't I go first? And I've got a story that I read about in nature. And it's based on a paper in science advances. Now, it has kind of a snigger factor to begin with. But actually, it could be a life-saving treatment. And it's about eyedrops made from pig semen.

Wow, didn't see that coming. Right. So let's back it up. This story focuses on a cancer of the retina called retinoblastoma. Now, thankfully, this is a rare type of cancer, but typically it affects young children, those under five. Now, it can be

successfully treated if it's caught early enough, but the treatment, as you might imagine,

involves injecting drugs into the eye and chemo, laser therapy, these sorts of things.

And this can result in loss or damage to eyesight and, of course, the side effects that come

with chemo as well.

And so a team were looking for another way to penetrate the barrier around the retina

and deliver drugs directly into the eyes. And this is where the pig semen comes in.

So why do they think to use pig semen? What's that got to do with it?

Do you know what? That is a fair question, Lizzie, and it is a bit of a leap between the two.

But there is a link. Now, key to this are particles. Essentially little bubbles they are. They're called exosomes.

Now, these are released by almost all cells in the body. But the exosomes in semen, well, they contain a lot of molecules that sperm need to do their job.

Now, this includes the ability to open and close what are called tight junctions.

Now, these are gaps between cells where they're kind of stuck together.

And they need to do this on the way to fertilize an egg.

And the researchers thought, well, hang on a minute.

Maybe we can use

this ability to get between cells to deliver something into the eye. And that's what they've

done in this case. So is this something that's unique to pig semen or is this just like a mammal

semen thing? Well, it's not unique to pigs, but pigs are used a lot in the biochemical

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