Tissue engineering of corneal stroma via melt electrowriting

Abstract

The cornea serves as the main refractive component of the eye with the corneal stroma constituting the thickest component in a stratified layered system of epithelia, stroma, and endothelium. Current treatment options for patients suffering from corneal diseases are limited to transplantation of a human donor cornea (keratoplasty) or to implantation of an artificial cornea (keratoprosthesis). Nevertheless, donor shortage and failure of artificial corneas to integrate with local tissue constitute important problems that have not been yet circumvented. Recent advances in biofabrication have made great progress toward the manufacture of tailored biomaterial templates with the potential of guiding partially or totally the regeneration process of the native cornea. However, the role of the corneal stroma on current tissue engineering strategies is often neglected. Here, we achieved a tissue‐engineered corneal stroma substitute culturing primary keratocytes on scaffolds prepared via melt electrowriting (MEW). Scaffolds were designed to contain highly organized micrometric fibers to ensure transparency and encourage primary human keratocytes to self‐orchestrate their own extracellular matrix deposition and remodeling. Results demonstrated reliable cell attachment and growth over a period of 5 weeks and confirmed the formation of a dense and highly organized de novo tissue containing collagen I, V, and VI as well as Keratocan, which resembled very closely the native corneal stoma. In summary, MEW brings us closer to the biofabrication of a viable corneal stroma substitute.

Biocompatible Synthetic Polymers for Tissue Engineering Purposes

“…The alignment significantly improved the proliferation of corneal stem cells in vitro and the expression of the relevant gene markers . A viable synthetic stroma substitute was developed in vitro using PCL and melt electrowriting . Due to its chemical structure with cross-links and long aliphatic chains, PGS is an amorphous and elastic polymer, both being very attractive properties for corneal TE.…”

“…37 A viable synthetic stroma substitute was developed in vitro using PCL and melt electrowriting. 199 Due to its chemical structure with crosslinks and long aliphatic chains, PGS is an amorphous and elastic polymer, both being very attractive properties for corneal TE. When combined with PCL, aligned nanofibers can closely mimic the native cornea and are more hydrophilic and therefore improve cell proliferation when compared with PCL alone.…”

Engineering Complex Anisotropic Scaffolds beyond Simply Uniaxial Alignment for Tissue Engineering

“…[70] This result provides an opportunity for exploiting new regenerative strategies for corneal stroma. Indeed, the corneal stroma scaffolds with an orthogonal arrangement of micro/nanofibers made of various biomaterials such as collagen, [94,169] PCL, [152,208] and poly(ε-caprolactone)-poly(ethylene glycol), [151] were achieved using order stacking and 3D printing approaches. Although the scaffolds prepared from collagen fibrils highly recapitulate the biological properties and transparent functions of the native corneal stroma, it is a monumental challenge to achieve acceptable mechanical strength, enabling firm integration with surrounding ocular tissue.…”

Detection of Limbal Stem Cells Adhered to Melt Electrospun Silk Fibroin and Gelatin-Modified Polylactic Acid Scaffolds

“…Real-size aortic roots with the sinuses of the Valsalva and a tri-layered fiber architecture were produced by melt electrowriting to support the adhesion of human umbilical vein smooth muscle cells [ 21 ]. Similarly, a viable corneal stroma substitute was designed by culturing human keratocytes onto melt electrowritten highly organized fibrous PCL, which resulted in the formation of a new tissue comprising keratocan and collagen I, V, and VI [ 22 ]. Corneal stroma replacement was also suggested to be grown onto melt electrowritten PCL with an orthogonal 3D arrangement, showing deposited collagen fibrils of the corneal stromal cells laid entirely within and across the open pores of the scaffold.…”