Human corneal endothelial cell growth on a silk fibroin membrane

Tissue engineering of the cornea could overcome shortages of donor corneas for transplantation and improve quality. Our aim was to grow an endothelial layer on a substratum suitable for transplant. Silkworm (Bombyx mori) fibroin was prepared as 5 μm thick transparent membranes. The B4G12 cell line was used to assess attachment and growth of human corneal endothelial cells on fibroin and compare this with a reference substratum of tissue-culture plastic. To see if cell attachment and proliferation could be improved, we assessed coatings of collagen IV, FNC Coating Mix® and a chondroitin sulphate–laminin mixture. All the coatings improved the final mean cell count, but consistently higher cell densities were achieved on a tissue-culture plastic rather than fibroin substratum. Collagen-coated substrata were the best of both groups and collagen-coated fibroin was comparable to uncoated tissue-culture plastic. Only fibroin with collagen coating achieved cell confluency. Primary human corneal endothelial cells were then grown using a sphere-forming technique and when seeded onto collagen-coated fibroin they grew to confluency with polygonal morphology. We report the first successful growth of primary human corneal endothelial cells on coated fibroin as a step in evaluating fibroin as a substratum for the transplantation of tissue-constructs for endothelial keratoplasty.