- The new 3D printed corneas will bring down the need of cornea donors.
- Using this technique, the entire cornea can be printed within 10 minutes.
- However, it will take several years before doctors could successfully replace it with an actual cornea.
According to the World Health Organization, more than 10 million people worldwide need surgery to prevent trachoma – a contagious bacterial infection that causes corneal blindness. Also, about 5 million people are suffering from total blindness because of corneal scarring.
Despite of a decent number of cornea donors, there is a huge difference between supply and demand of transplantable corneas. That’s why scientists are working on artificial corneal substitutes for the last couple of years.
Now, researchers at the Newcastle University have 3D printed artificial corneas using a special solution, “bio-ink”. The technology will help us in the future to bring down the need of cornea donors, leaving a positive impact on patients and families living with sight loss.
Cornea is the outermost (protective) layer of the eye, which plays a crucial role in focusing vision. Its surface accounts for nearly 80 percent of the eye’s total refractive power. In order to develop an engineering framework of functional corneal substitutes, it’s important to carefully design rotational curvature that provides optical refractive power.
How Did They Do It?
Scientists mixed human corneal stromal cells (obtained from a healthy donor) with sodium alginate and methacrylated type I collagen to produce a unique gel (what they call “bio-ink”) that could be 3D printed.
They used this gel in an inexpensive 3D bio-printer; it ejected the bio-ink in concentric circles to create cornea-like shape. The speed of the printing process was more than impressive – it only took 10 minutes to print the entire cornea.
The mixture of collagen and alginate creates a solution strong enough to hold the shape of stem cells while keeping it alive at room temperature. To squeeze it out of the printer’s nozzle, the solution isn’t made too hard.
With bio-ink, users can print tissues without worrying about the cell growth. They can even configure the shape of a cornea according the patient’s specifications. To speed up the process, dimensions of tissue could be extracted from patients’ cornea by scanning their eye.
These scans are expressed in the form of a unique G-code, which could be automatically measured by 3D printing software at specific resolutions. The capability of replicating things like undercuts, concavity and convoluted patterns is function of the complexity of 3D figures, such as circles, lines, and points.
The final phase includes remodeling of 3D printed construct in the presence of suitable physiological cues to ensure that it grows appropriate structural, functional and biomechanical properties.
Finally, scientists evaluated the printing accuracy by quantifying peripheral and central thickness of the corneal construct. Furthermore, they evaluated viability of encapsulated corneal keratocytes on first and seventh day of post-printing.
Researchers holding 3D printed cornea
The artificial cornea is not yet ready for clinical use. Researchers plan to test it further for longer duration and see if there is any side effect(s). More specifically, they will examine stromal cell phenotype, biocompatibility of 3D printed cornea, and its capacity to support epithelial cell growth.
Bottom line: it will take several years before doctors could successfully replace it with an actual cornea.