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Mark Ahearne. 1 Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland. 2 Department of Mechanical and Manufacturing Engineering, School of Engineering, Trinity College Dublin, Dublin, Ireland.
Amy P. Lynch. 1 Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland. 2 Department of Mechanical and Manufacturing Engineering, School of Engineering, Trinity College Dublin, Dublin, Ireland.
Address correspondence to: Mark Ahearne, PhD, Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland, E-mail: [email protected]
Introduction
Corneal blindness is among the most common causes of blindness worldwide affecting millions of people. Physical injuries, chemical scars, and medical conditions, such as keratoconus or Fuchs dystrophy, can result in permanent blindness if not properly treated. In many cases keratoplasty is required to alleviate suffering and restore vision, however, in many countries there is an insufficient supply of corneal tissue suitable for transplantation. In addition, not all patients requiring a new cornea are suitable for allografts. For these reasons, researchers have been investigating alternative methods of obtaining corneal tissue, including by tissue engineering.
Tissue engineering has the potential to develop corneal tissue in vitro. There has been some success in the use of tissue engineering in ophthalmology, particularly in the development of corneal epithelium cultured from limbal-derived stem cells on a biomaterial substrate that is suitable for transplantation1-3 and more recently in the development of carriers for endothelial cells.4-7 The corneal stroma represents a more challenging tissue to engineer due to its thickness, composition, complex structure, and need for transparency. To date, the most common approaches to engineering the corneal stroma have involved either the development of three-dimensional hydrogels8-12 or the use of decellularized corneal scaffolds.13-15
While several different hydrogels have been investigated, many of these lack the chemical composition required by the native corneal stromal cells to maintain their native keratocyte phenotype. Decellularized scaffolds can maintain the composition and structure of native cornea, but these can be difficult to recellularize due to their high density and limited porosity.
Recently, hydrogels derived from the extracellular matrix of decellularized tissues have been under investigation for use in engineering several tissue types, including neural, cardiac, and musculoskeletal tissues16-21 ; although, to date, this...