Tissue engineering has produced a clinically successful equivalent of human skin (Integra). Similar efforts, applied to the cornea, an avascular and relatively acellular connective tissue, should also yield beneficial results. Although two corneal constructs have been produced, there is little hope of their use in the clinic in the near term, even as temporary scaffolding. The problem lies in the reproduction of the simple but highly organized stroma. The ability of the cornea to admit light, provide strength and generate a smooth spherical surface depends critically on its nanoscale structure. In this Phase I proposal, specific aim 1 describes the design of a novel collagen reactor capable of producing thin sheets of aligned collagen fibrils. The system is based on the well-defined science of spin coating and is designed to create a microenvironment promoting collagen tibrillogenesis in extremely thin sheets.
In specific aim 2, a slight modification allows the orthogonal stacking of these sheets of aligned fibrils, mimicking the primary corneal stroma.
Specific aim 3 proposes to create a rudimentary three-layered corneal construct by culturing human epithelium and endothelium onto the engineered stroma. Such an effort, focused on the stroma, is critical to the eventual generation of a biomaterial suitable for use in corneal repair or replacement therapy.
Between 40,000 and 50,000 cornea replacement surgeries are performerd in the United States every year, with an average cost of harvesting donor corneas ranging between $1,000-$2,000, yielding a market of $100M. Donor shortages are expected to grow in the future, as European and third world markets depend more on US-based eye banks, demographic changes limit donor pools, and keratorefractive surgery becomes more prevalent. A market exists for an artificial cornea, particularly one that can potentially be plated with a patient's own cells, which will reduce the chances of organ rejection.
