Ghosh Anwesha, Bera Ashis Kumar, Ghosh Soham, Singh Vivek, Basu Sayan, Pati Falguni
Department of Biomedical Engineering, Indian Institute of Technology Hyderabad, Kandi, Sangareddy 502284, Telangana, India.
Centre Ocular Regeneration, Prof. Brien Holden Eye Research Centre L.V. Prasad Eye Institute, Hyderabad 500034, Telangana, India.
Biofabrication. 2024 Dec 4;17(1). doi: 10.1088/1758-5090/ad9409.
Bioprinting a resilient yet optically transparent corneal tissue substitute remains a challenge. In this study we introduce an innovative methodology aimed at bolstering the mechanical and optical attributes of silk fibroin (SF) hydrogels, pivotal for the progression of cornea tissue engineering. We devised a unique eosin Y-based photoinitiator system to instigate di-tyrosine linkages within highly concentrated pristine SF solutions under green light exposure. This pioneering technique resulted in SF hydrogels fortified by dityrosine covalent bonds, preserving exceptional transparency and soft elastomeric qualities devoid of spontaneous transitions to stiff, opaque beta-sheet conformations. Furthermore, we synergistically combined SF with decellularized cornea matrix (DCM) hydrogel, leveraging photo-polymerization under green light followed by thermal gelation to establish resilient and stable gel formation. The ensuing dual crosslinked hybrid hydrogels exhibited superior mechanical and thermal resilience in comparison to dual crosslinked DCM hydrogels. The inclusion of SF in DCM further augmented the hydrogel's elasticity and shear recovery, positioning it as an optimal bioink for cornea bioprinting endeavors. During the extrusion printing process, photocrosslinking of the bioink superficially fortified SF and DCM polymer chains via di-tyrosine linkages, furnishing initial stability and mechanical fortitude. Subsequent post-printing thermal gelation further reinforced collagen chains through self-assembly. Notably, the bioprinted cornea constructs, housing human limbal mesenchymal stem cells, manifested transparency, structural integrity, and optimal functionality, underscored by the expression of keratocyte proteoglycans. In summation, our engineered 3D constructs exhibit promising potential forapplications in cornea tissue engineering, marking a significant stride forward in the field's advancement.
生物打印一种具有弹性且光学透明的角膜组织替代物仍然是一项挑战。在本研究中，我们引入了一种创新方法，旨在增强丝素蛋白（SF）水凝胶的机械和光学属性，这对于角膜组织工程的进展至关重要。我们设计了一种独特的基于曙红Y的光引发剂系统，以在绿光照射下促使高浓度原始SF溶液内形成二酪氨酸键。这项开创性技术产生了由二酪氨酸共价键强化的SF水凝胶，保持了出色的透明度和柔软的弹性体特性，不会自发转变为僵硬、不透明的β-折叠构象。此外，我们将SF与脱细胞角膜基质（DCM）水凝胶协同结合，利用绿光下的光聚合作用，随后进行热凝胶化，以形成有弹性且稳定的凝胶。与双交联的DCM水凝胶相比，由此产生的双交联混合水凝胶表现出卓越的机械和热弹性。在DCM中加入SF进一步增强了水凝胶的弹性和剪切恢复能力，使其成为角膜生物打印努力的最佳生物墨水。在挤出打印过程中，生物墨水的光交联通过二酪氨酸键在表面强化了SF和DCM聚合物链，提供了初始稳定性和机械强度。随后的打印后热凝胶化通过自组装进一步强化了胶原链。值得注意的是，植入人角膜缘间充质干细胞的生物打印角膜构建体表现出透明度、结构完整性和最佳功能，角膜细胞蛋白聚糖的表达突出了这一点。总之，我们设计的3D构建体在角膜组织工程应用中展现出了有前景的潜力，标志着该领域取得了重大进展。
