Hybrid Cornea: Cell Laden Hydrogel Incorporated Decellularized Matrix

Abstract

The decellularization protocols applied on the corneal stromal constructs in the literature usually fail to provide a corneal matrix with sufficient mechanical and optical properties since they alter the extracellular matrix (ECM) microstructure. In this study, to overcome these limitations, a hybrid cornea stromal construct was engineered by combining gelatin methacrylate (GelMA) and decellularized ECM. Photo-cross-linking of impregnated cell laden GelMA in situ using different UV cross-linking energies (3200, 6210, and 6900 μJ/cm2) and impregnation times (up to 24 h) within a decellularized bovine cornea enhanced light transmission and restored lost mechanical features following the harsh decellularization protocol. The light transmittance value for optimized hybrid constructs (53.6%) was increased nearly 10 fold compared to that of decellularized cornea (5.84%). The compressive modulus was also restored up to 6 fold with calculated values of 5040 and 870 kPa for the hybrid and decellularized samples, respectively. These values were found to be quite close to that of native cornea (48.5%, 9790 kPa). ATR-FTIR analyses were carried out to confirm the final chemical structure. The degradation profiles showed similar decomposition behaviors to that of native cornea. In vitro culture studies showed a high level of cell viability and cell proliferation rate was found remarkable up to the 14th day of the culture period regardless of selected UV energy level. The methodology used in the preparation of the hybrid cornea stromal constructs in this study is a promising approach toward the development of successful corneal transplants.

Biomedical application of photo-crosslinked gelatin hydrogels

“…The decellularization cornea applied in cornea stroma engineering can not mimic the environment of extracellular matrix well because it changes the original ECM micro-environment during the decellularization process. In order to solve this problem Uyanıklar et al [133] fabricate a novel scaffold which is a combination of GelMA and decellularized matrix. They reported that this material has better compressive modulus (5040 and 870 kPa) and light transmittance value (53.6%), due to the special structure of GelMA makes up for the inherent shortcomings of the decellularization matrix.…”

Hydrogels as Emerging Materials for Cornea Wound Healing

“…A cell laden hybrid hydrogel made from GelMA incorporated with decellularized bovine cornea matrix showed an increased light transmittance value (around ten‐fold increase), compressive modulus (around six‐fold increase) and degradation profile close to native cornea compared with decellularized bovine cornea matrix. [ 76 ] In addition, modification of agarose hydrogels with fish‐derived gelatine exhibited >96% transmittance of visible light, tensile strength and young's modulus of 49–60 and 525–596 MPa, respectively, with enhanced corneal endothelial cells (CECs) long‐term viability (⩾4 weeks) and attachment compared with agarose hydrogels alone and modified with GRGD, lysine and poly lysine. [ 77 ] Kong and colleagues [ 78 ] used electrospinning technique to improve the biomechanical and biological properties of gelatine‐based hydrogels with highest biomimetics activity on limbal stromal stem cells differentiation toward keratocytes or fibroblasts, phenotype maintenance, and in vivo tissue regeneration of the defected cornea in rabbit model.…”

“…2019 [76] Agarose-gelatine hydrogels Rabbit CECs Attachment and viability over 4 weeks. Over 96% transmittance of visible light.…”

Recent Advances in Natural Materials for Corneal Tissue Engineering

“…An alternative to helical type I collagen with secondary structure is the use of gelatin or methacrylated gelatin (GelMA) [ 12 , 56 , 67 , 68 , 69 , 71 , 72 , 73 , 74 , 75 , 76 , 77 ]. Gelatin, a denatured and hydrolyzed form of collagen, and its methacrylated form, have demonstrated broad applicability across many tissue engineering applications due biocompatibility, tailorable mechanical properties, low cost, ease of processing, and transparency [ 76 , 78 ], making them an attractive biomaterial for ocular applications.…”

“…Studies use many corneal stromal cell sources for investigating cell-material interactions in stromal tissue engineering strategies, including human CKs, bovine CKs, human CSCs, human LSSCs, and rat LSSCs [ 31 , 70 , 71 , 72 , 75 , 92 , 94 , 107 ]. The use of biomarkers to identify stromal cells include keratocan, lumican, α-actinin, aldehyde dehydrogenase 1 family, member A1 (ALDH1A1), and aldehyde dehydrogenase 3 family, member A1 (ALDH3A1).…”