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TLDR: Scientists put (safe) bacteria into contacts to help prevent dry eyes.
From Figure 5 in the paper. The living contact with a close up showing where the bacteria-factories are located within the contact lens. Credit: María Puertas-Bartolomé, Aránzazu del Campo, et al. Adv. Mat. 2024.
The Study: Self-Lubricating, Living Contact Lenses
Big Takeaways
Long-term contacts could be used for treating eye diseases or creating augmented vision contacts (hopefully sci-fi supervision).
Dry eyes are a huge issue with long-term contacts.
Materials that are lubricating and absorb water help prevent dry eyes.
They can be included in contacts, but leak out over time, making them not effective long-term.
Bacteria can produce commonly used lubricating/hydrating materials.
Including safe bacteria that produce the hydrating molecule hyaluronic acid makes living contact lenses to prevent dry eyes.
The Problem
Contacts. Specifically, getting dry eyes while wearing them. Dry eyes lead to people taking their contacts out early, using eye drops excessively, or just avoiding contacts all together. Even if the contacts themselves aren’t drying your eyes out, getting dry eyes with them in is a huge pain.
Making contacts that actively keep our eyes from getting dry would be a plus. This week, we’ll go through a paper doing just that by making the contacts “lubricant-secreting biofactories”.
The Solution
The authors focus on two main problems with contacts: 1) the contact retaining moisture and 2) being highly lubricating. To be effective, the contact needs both.
A common way to make this happen is to include some water-loving molecules in the contacts, but this has some issues. Mainly, the molecules leak from the contact over time, making them work less and less as the day goes on.
One such molecule, hyaluronic acid (HA), is well known in the skincare industry for its ability to absorb water. It also happens to be naturally produced, completely safe, and commonly found throughout your body.
Schematic of the living-contact lens. A ring around the edge contains live bacteria that produce the hydrating molecule hyaluronic acid. Figure 1 from the paper. Credit: María Puertas-Bartolomé, Aránzazu del Campo, et al. Adv. Mat. 2024.
In this week’s paper, the authors engineered a corynebacteria commonly found in soil to produce HA and embedded it in a contact lens. While in the lens, the bacteria constantly produces HA, giving a long-term source of the HA lubricant within the contact itself.
The authors pitched this living-contact as a way to make long term contacts for things like therapeutic lenses or augmented vision possible. So, they want to make contacts that could stay in your eye and stay lubricated for weeks. And they want the bacteria in them to make HA the whole time.
The living contacts produce hyaluronic acid over time. From Figure 4 in the paper. Credit: María Puertas-Bartolomé, Aránzazu del Campo, et al. Adv. Mat. 2024.
When they measured the amount of HA the living contacts produced, they found it steadily went up over at least 3 weeks (see graph above). In addition to just making the HA, their living contacts had lower friction than the same contact material without the HA producing bacteria, indicating they’ll be ok to use on the eye.
They didn’t do much to evaluate the efficacy of their living-contacts, but they make a compelling argument for the system as a new platform to develop off of.
Overall, I love the concept of living materials and finding ways to use living organisms in our materials. Obviously they need to be safe, but there are plenty of safe bacteria out there that we already live with every day.
Now, would I get these living contacts and actively put bacteria in my eye, even if it’s supposedly safe? I’m not sure. I know there’s bacteria throughout our bodies, on our skin, probably in our eyes, but I’d still hesitate. Would I try them if it gave me super vision or cured some eye disease I had? Probably so.
See you next week for more science,
Neil
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