“…The extracellular matrix of the corneal stroma consists primarily of collagen type I with a lower amount of collagen type IV and proteoglycans (Knupp et al, 2009;Hassell and Birk, 2010). Therefore, collagenous biomaterials such as collagen gels, and acellular porcine corneas are widely used as potential corneal substitutes (Liu et al, 2007;Fagerholm et al, 2009Fagerholm et al, , 2010Merrett et al, 2009;Duncan et al, 2010;Tanaka et al, 2011;Xiao et al, 2011;Yoeruek et al, 2011). As alternative approach, autogenic transplantation of collagen-rich tissues such as ligaments, tendons, and skin have been widely applied for the replacement of damaged tissue (Jackson and Simon, 2002;Antonogiannakis et al, 2005;de Vries Reilingh et al, 2007;Carey et al, 2009).…”