Research projects in corneal tissue engineering address issues of making a biocompatible non-biodegradable replacement cornea, and of developing a carrier surface for delivering cultured corneal epithelial cells to the damaged cornea.
In the first project the challenge is to make a non-degradable, biocompatible polymeric cornea substitute, which will take the place of organ donor corneal transplants in the future. This material needs to be mechanically and optically appropriate but more exacting than this, to have a surface that promotes the attachment and migration of corneal epithelial cells. Cell attachment is a major challenge that is being tackled in a BBSRC project between Steve Rimmer in Chemistry and Sheila MacNeil in Engineering Materials. This project also involves collaboration with Dr Nigel Fullwood, University of Lancaster, who has some 10 years expertise of working on corneal epithelial cell culture.
Above right: Human corneal epithelial cell line cultured on (a and b) acrylic acid coated contact lenses, (c) collagen, fibronectin and BSA (positive control substrate) and (d) uncoated contact lens (negative control substrate).
In a second project, we have are developing a contact lens as a carrier vehicle to deliver cultured cells from the laboratory to the patient. Damage to the cornea can be treated by the grafting of autologous cells cultured from the contra lateral undamaged eye (if this is available) or by the use of donor corneal epithelial cells (which then requires immunosuppression). One of the challenges is how to get the cells from the laboratory to the eye and sutured onto the eye in such a way that they provide immediate cover and good take.
In this work the approach is to develop a strategy whereby one uses a chemically modified contact lens to transfer the corneal epithelial cells to the eye. The development of this treatment brings together two very different fields of expertise:
- The development of an organ culture model allowing us to test the process.
- Surface chemistry expertise, allowing us to treat standard contact lenses with an acrylic acid coating deposited by plasma polymerisation to provide a suitable transfer surface.
Bringing these together, we have recently been able to demonstrate in our model system that corneal epithelial cells can be plated onto the modified contact lens and successfully transferred from the contact lens to the eye.
Right: Culture model with (a) intact epithelium (labelled with DAPI and phalloidin FITC), (b) a denuded epithelium (stained with fluorescein), (c) Limbal epithelial cells and (d) human corneal epithelial cell line after transfer from lens (labelled with CellTrackerTM Red).