Properties of Porcine and Recombinant Human Collagen Matrices for Optically Clear Tissue Engineering Applications

Abstract

Porcine and recombinant human atelocollagen I solutions were cross-linked with a water soluble carbodiimide at various stoichiometries and collagen concentrations (5-20 w/w %). The resulting hydrogels were clear and, when used as cell growth matrices, allowed cell and nerve visualization in vitro and in vivo. We have previously reported that, after six months of implantation in pigs' and rabbits' corneas, these robust hydrogels allowed regeneration of host cells and nerves to give optically clear corneas with no detected loss in thickness, indicating stable engraftment. Here, the biocompatible hydrogel formulations leading to this novel in vivo performance were characterized for amine consumption, gel hydration, thermal properties, optical clarity, refractive index, nutrient diffusion, biodegradation, tensile measurements, and average pore diameters. Gels with excellent in vitro (epithelial overgrowth, neurite penetration) and in vivo performance (clarity, touch sensitivity regeneration) had 4-11 nm pores, yet had glucose and albumin diffusive coefficients similar to mammalian corneas and allowed neurite extension through the gels.

Biofunctionalization of collagen for improved biological response: Scaffolds for corneal tissue engineering

“…However, there was no obvious trend with increasing peptide concentration, potentially due to the fact that the peptide concentration in the gels was higher than needed to promote neurite extension or that the differences on peptide concentration on the gel surfaces were relatively small. While it would be preferable to assess nerve ingrowth into these materials, these preliminary studies, similar to those performed by other groups [19,20], clearly demonstrate the potential of these materials for the support of nerves. Ongoing nerve ingrowth studies may provide additional insight into the effect of peptide concentration on innervation of tissueengineering scaffolds.…”

The Development of a Tissue-Engineered Cornea: Biomaterials and Culture Methods

“…Recently, Griffith et al have developed a simple carbodiimide (EDC/NHS) crosslinked collagen based hydrogel, which is optically clear (99% light transmission), and has a refractive index and glucose permeability comparable to the normal human cornea (56,57). In in vitro evaluations, no local cytotoxicity, genotoxicity, or systemic cytotoxicity was observed, and epithelial growth rates were unaffected.…”

Crosslinked collagen–gelatin–hyaluronic acid biomimetic film for cornea tissue engineering applications

“…Cornea is the outermost layer of the eye and the main refractive element that is responsible for transmission of light to the retina [1]. Corneal disease is a major cause of blindness worldwide.…”