Self-curvature to become next step for 3D bioprinted corneas

In 2018 Newcastle University researchers made headlines after 3D bioprinting viable human corneas. Though years from transplantation, the development is a significant step forward for the field, and demonstrates real potential for combating transplant shortage.

Now, another team from the same university have come up with the foundations for the next stage of 3D bioprinted corneas. Published in a paper for Advanced Functional Materials this latest advancement describes the potential of self-curving, “4D” corneas.

Origami corneas

The new research, also from Newcastle University’s Institute of Genetic Medicine, has been conducted by Martina Miotto, Ricardo M. Gouveia, Ana M. Ionescu, Francisco Figueiredo, Ian W. Hamley, and Che J. Connon.

Rather than a strictly 4D bioprinting approach, i.e. with the use of a bioprinter, instead the paper outlines the way certain materials can be combined in order to contract and transform. As Miotto explains, “My colleagues and I recently found a way to make gel containing live corneal cells self-assemble into the correct pattern, like a piece of paper that folds itself into an origami design.”

The base material for this experiment is a collagen gel which contains corneal cells. Naturally, as these cells proliferate, they grow to become a curved, cornea-like structure. Left to form without a guide though, the result can be irregular.

The uneven folding of collagen gels laced with cornea cells. Image via Advanced Functional Materials
The uneven folding of collagen-cell gels with and without the addition of peptide amphiphiles (PA). Image via Advanced Functional Materials

Tuning the transformation

By adding naturally self-assembling peptide-based molecules to the collagen gel, the Newcastle University team discovered that the material contracted less. “From this observation,” Miotto adds, “we were able to design the gel mixture to contract by different amounts in different places to adopt a specific shape.”

The result was “a circular shape divided into two rings, with peptide amphiphiles located either in the outer ring or in the center” as seen in the image below.

In this arrangement, one part of the gel contracted more than the other, allowing it to curve into a corneal-shape. Overall, the transformation took around 5 days to complete.

The next step for 3D bioprinting? 

Having demonstrated the 4D capability of this biomaterial, the Newcastle researchers are hopeful that this method could have future applications for the field. “In this context,” the study concludes, “these constructs can be considered as potential alternatives of corneal stroma tissue for transplantation.”

“For instance, the concept of self-curving design could easily be integrated into current additive manufacturing techniques such as 3D bioprinting […] Such integration would also allow automation, as well as a higher degree of consistency and precision in the spatial localization of the different cellular and matrix components of the composite gels.”

Full results of the recent Newcastle University study are published online in the paper “4D Corneal Tissue Engineering: Achieving Time‐Dependent Tissue Self‐Curvature through Localized Control of Cell Actuators.”

Other institutions around the world looking at the potential of 3D bioprinted corneas include North Carolina biotechnology Precise Bio, that recently opened a specialist ophthalmology facility for this purpose; and a team at the Instituto de Investigación Biomédica del Hospital La Paz in Madrid.

Are Newcastle University’s 3D bioprinted corneas your Medical Application of the Year? Could these also be contenders for Research Team of the Year? Make your nominations now in the 2019 3D Printing Industry Awards.

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Featured image shows a macro view of the human eye, iris, pupil, eye lashes, eye lids. Photo via Shutterstock.