Compressed collagen intermixed with cornea-derived decellularized extracellular matrix providing mechanical and biochemical niches for corneal stroma analogue.

Compressed collagen is a promising scaffold for corneal stroma analogue due to its facile incorporation of keratocytes while mimicking the mechanical niche of a native cornea with dense collagen fibrillar structures. However, it does not offer the sufficient biochemical niche crucial for in vivo-like quiescent keratocyte phenotype. In this study, we engineered a scaffold for a corneal stroma analogue that mimics both the mechanical and biochemical niches of the corneal stroma by introducing cornea-derived decellularized extracellular matrix (Co-dECM) to the collagen compression process. The compressed collagen intermixed with Co-dECM (COLEM; Co-dECM content, <50 wt%) maintained a uniform structure and showed an elastic modulus and tensile strength on the order of 100 kPa, which is comparable with that of conventional compressed collagen. The COLEM with the 50 wt% Co-dECM content was found to possess 2-fold higher amount of the glycosaminoglycans as compared to the compressed collagen. The biochemical components of Co-dECM in the COLEM were verified to significantly promote the expression of quiescent keratocyte-specific genes, i.e., KERA and ALDH3A1, while improving the optical transmittance of the COLEM by reducing the diameter of collagen fibrils. The ability of the COLEM to construct multicellular in vitro corneal tissue was demonstrated by an additional corneal epithelial cell culture. The results support the hypothesis that COLEM has strong potential use in the development of corneal equivalent for in vitro models and tissue transplantation.