Novel techniques in corneal regeneration and bioscaffold engineering

Restoration of corneal transparency and a functioning epithelium and stroma may involve multiple procedures that are limited by availability of donor tissue and an inability of host tissue to self-regenerate. We present a tissue-engineered collagen-based hydrogel bioscaffolds for regenerating a transparent stroma and providing the additional possibility of carrying and delivering corneal stem cells to the stroma or epithelium. We present in vitro results of bioscaffold compatibility with epithelial and stem cells, and techniques for the optimal implantation of scaffolds using femtosecond laser surgery. Using models of in vivo bioscaffold implantation in the rabbit, we evaluate transparency, stability, and controlled degradation characteristics of the scaffolds. Tissue engineering provides the opportunity to tune the size, thickness, transparency, homogeneity and degradation rate for specific applications. For example, the bioscaffold may be used to substantially thicken the stroma or allow non-invasive in vivo tracking of its controlled degradation as it releases therapeutic cells. In vitro and in vivo results with bioscaffolds are presented that provide the basis for further preclinical and clinical development.