Purpose:
Tissue engineered corneas provide an alternative for patients who respond poorly to donor corneas. A current limitation is minimal host tissue integration that can lead to infection, melting, or extrusion. These synthetic devices lack cues to promote cell adhesion. To overcome this, natural materials have been investigated as adhesive scaffolds. However, these typically require toxic crosslinkers to impart sufficient mechanical strength. We have engineered a hybrid scaffold of natural and synthetic materials by utilizing superporous technology to incorporate stromal cells and type 1 collagen in a hydrogel.
Methods:
Unique to our design is the integration of type 1 collagen within a polyethylene glycol diacrylate (PEGDA) based superporous hydrogel (SPH) skirt to enhance corneal fibroblast adhesion. A dehydrated SPH swells rapidly in a cell-collagen solution, incorporating this via capillary action. A clear optic core of nonporous PEGda is filled in the center. (See Figure 1.) Adhesion studies were performed by staining with CD-29 and vinculin antibody. Light transmission and refractive index were measured with a UV-Vis spectrophotometer and refractometer.
Results:
Fibroblasts in collagen adhere to the extracellular matrix (ECM). After 1 week, collagen enhances adhesion and cell retention as compared to noncollagenous scaffolds. Stress fibers and adhesive contacts are apparent in fibroblasts loaded in the collagen-SPH scaffold. In contrast, cells loaded without collagen show a round morphology, binding to other cells rather than ECM. The central optic has a refractive index of 1.34, similar to natural cornea (1.37).
Conclusions:
Integrating collagen and cells within a superporous PEGDA scaffold, increases stromal cell adhesion and survival. While many attempts were made to develop synthetic macroporous corneal replacements, few, if any, incorporated a bioadhesive material such as collagen. This hybrid includes a collagenous microenvironment while maintaining mechanical integrity.
Keywords: keratoprostheses • cornea: stroma and keratocytes • transplantation