From the front page of the news to your home. Learning about creating artificial corneas through play based learning.
What you'll learn:
What is a cornea? Why are corneas important? How can we make a cornea?
The clarity, and shape of a cornea determine how well a person can see.
Scientists recently created the world's first 3D printed living transplant tissue in the form of corneas. The cornea is the outside lens of your eye, and does much of the work when it comes to focusing the image. Damage to the cornea can lead to vision impairment of blindness, and there are over 12 million people around the world waiting for a transplant.
In this lab we will take a hands-on look at how the scientists designed the process that might help millions see clearly. We will make our own 'cornea' lenses, and discover different types of cornea problems.
Add depth to this project by reading our interview with the researcher Dr. Che Connon!
Oil polymer clay
A hands-on demonstration of synthetic cornea creation.
The 3D printers that scientists use to print living tissue samples are pricey – in the range of $5,000-10,000. Not only that but the materials and processes they use require a lab setting. This project won’t use pricey equipment or tricky solutions – instead of making real corneas, we will be making corneas our of molded ice. This will act as a lens that we can view the world through and engage with this cutting-edge discovery.
In this project, we will take a look at what the cornea is used for in our eye, as well as how we can create our own set of lenses at home using similar practices.
1. Make your bio-ink.
In this project, our ‘bio-ink’ will be made out of ice. To make a lens out of ice we want as clear of ice as possible. This means eliminating impurities like dirt, minerals, and gasses.
While we can’t get pure, pure water, we can start with the best we can buy – and that means buying distilled water. Distilled water is water that has been boiled, collected, and bottled. The boiling process boils off only water molecules and leaves other impurities, like salt, behind in the pan.
This gets rid of the minerals in the water, but not the gas. While we can’t fully remove the gas in our water at home, we can help it along. We do this by boiling the water for 5-10 minutes, letting it cool, and boiling it again for another 5-10 minutes. As the water, and thus the gas, gets hotter, the gas expands (thanks to the ideal gas law) and comes out of solution. You can see this in all the tiny bubbles that begin to form just before water boils. Those were all gasses dissolved in the water – bubbles that would make our ice more cloudy if left in.
What happens in the lab?
In the lab, the bio-ink is created out of a mix of collagen, alginate, and stem cells. The collagen and alginate form a scaffold, or bridge tissue, that allows the stem cells to survive inside. As the stem cells grow they create their own connections and scaffolding which ultimately produces a transplantable cornea.
2. Create your mold
If we want to freeze our water in the shape of a lens, we have to create the negative shape to fill and place in the freezer. Without that support, the water will just form a puddle at the bottom of the freezer.
Using the oil based polymer form a negative mold of the shape you want for your lens. A simple cornea shaped lens could be made by creating a round thumbprint type impression in the clay.
What happens in the lab?
One of the fundamental building blocks that led to this discovery was the use of 3D printed plastic molds. These molds are created based on the size, and shape, of the cornea that needs replacing, then the negative shape is printed on a traditional 3D printer. This plastic negative mold serves as a bed for the bio-ink to lie on as it is being printed, which allows the bio-ink to have less structure, as the plastic mold initially holds everything in place.
3. Freeze your lens.
Fill your mold with water and set it in the freezer. You might have some additional success in creating clearer ice by allowing your freezer to be set at a warmer temperature, which will freeze the ice more slowly.
What happens in the lab?
A permanent structure is grown into the 3D printed bio-ink over the course of a week. During this time the stem cells harvested from donor corneas creates its own scaffolding to hold the cornea together, even under a variety of mechanical stress tests.
4. Remove and test your lens.
Once your lens is frozen it can be used to discover the world around you. How does your ice cornea change your view when you look through it? You can add measurement and analysis to this project by measuring the focal length of your lens (or lenses).
The ice we make for this project will absolutely have some bubbles in it. It is just impossible to get all the gas out of the water or to freeze it slow enough in a home setting. If you are getting frustrated with the bubbles in your mini lenses you can try building a giant lens using an ultra clear, store-bought ice block.
You can chip at this ice block to get an initial shape, then use sandpaper or a hot rag to smooth out the lens. One this size can be used to start a fire, bringing a whole lot more fun from the saying ‘fire and ice’!
Learning about, and experimenting with, corneal diseases.
Cloudy corneas (Lattice corneal dystrophy)
A cloudy cornea can lead to impaired vision or blindness. There are many causes of cloudy corneas, some are genetic, while others are environmental infections or vitamin deficiencies. The only way to repair cloudy corneas is to replace the cornea with a transplant.
See it in your project: You can see the effect of cloudy corneas in your project by creating cloudy ice (by using tap water instead of our boiled distilled water). What is it like to look through the cloudy ice versus clear ice? Compare and contrast what your world would be like if you had cloudy corneas.
Disfigured corneas (Keratoconus)
Keratoconus is one of many types of shape disorders in the cornea. Since the cornea does about 75% of the focusing of images our eyes see, changes in shape can vastly affect vision. This changes in shape can be caused by genetic diseases, accidents, scarring, and more.
See it in your project: You can see the effect of shape on image formation by creating a few different lenses, all with vastly different shapes. Then look through each shape. How would your world look if the shape of your cornea was disfigured? Can you think of a simple, real-world way to feel this in real life?