Development of Hydrogel‐Based Keratoprostheses: A Materials Perspective

Abstract

Research and development of artificial corneas (keratoprostheses) in recent years have evolved from the use of rigid hydrophobic materials such as plastics and rubbers to hydrophilic, waterswollen hydrogels engineered to support not only peripheral tissue integration but also glucose diffusion and surface epithelialization. The advent of the AlphaCor core-and-skirt hydrogel keratoprosthesis has paved the way for a host of new approaches based on hydrogels and other soft materials that encompass a variety of materials preparation strategies, from synthetic homopolymers and copolymers to collagen-based bio-copolymers and, finally, interpenetrating polymer networks. Each approach represents a unique strategy toward the same goal: to develop a new hydrogel that mimics the important properties of natural donor corneas. We provide a critical review of these approaches from a materials perspective and discuss recent experimental results. While formidable technical hurdles still need to be overcome, the rapid progress that has been made by investigators with these approaches is indicative that a synthetic donor cornea capable of surface epithelialization is now closer to becoming a clinical reality.

A Biosynthetic Alternative to Human Donor Tissue for Inducing Corneal Regeneration: 24-Month Follow-Up of a Phase 1 Clinical Study

“…Nerve regeneration has not been previously possible in corneal prosthetics (6,7,12), nor has it been described in any other alternative corneal substitute tested in humans. Sub-basal epithelial nerves regenerated in nine of ten patients receiving implants and increased in density during the first two years after surgery.…”

“…Recently, however, developments in bioengineered corneal substitutes designed to replace the full or partial thickness of damaged or diseased corneas have been reported (6,7). These range from fully synthetic prostheses (eg.…”

“…These range from fully synthetic prostheses (eg. keratoprostheses) made from poly-methacrylates, that aim to replace the cornea's refractive function (6,7), to tissue-engineered cell-based constructs (8) and hydrogels that also permit the integration of the implant and regeneration of the host tissues (9)(10)(11). At present, keratoprostheses are the only non-allogeneic option approved for human use.…”

“…Their use is therefore limited to cases in which allogeneic tissue has failed repeatedly or is contraindicated (6,7,12).…”

Artificial corneas: a regenerative medicine approach

“…[5][6][7][8] This study, therefore, is not meant as a review of the subject. Rather, our aim is to focus on the regenerative medicine approach to corneal transplantation, and in particular our own research progress, and those of others in the field in regenerating damaged corneas.…”