Highly transparent and elastic acellular swim bladder with potential application in cornea implantation

Corneal injury is the leading cause of blindness worldwide, and corneal transplantation remains a critical clinical treatment for restoring vision. However, the shortage of corneal donors greatly limits the application of this therapy. Although some biological corneal scaffolds such as collagen hydrogels and decellularized amniotic membranes, have emerged in recent years, their clinical efficacy is unsatisfactory because of poor tissue integration caused by the difficult suturing required and poor biomechanical properties of the scaffolds. To address these shortcomings, a decellularized swim bladder corneal scaffold was developed in this research. Specifically, using a freezing and thawing process, with 0.5% sodium deoxycholate and nuclease, the natural elastin fibers were preserved during the decellularization process, which enhanced the elastic properties of the scaffold. Dehydration and cross-linking increased the light transmittance of the decellularized swim bladder to 93.1 ± 0.8%, which was slightly higher than that of human corneas. Furthermore, cross-linking further improved the mechanical properties of the scaffolds (circumferential fracture tensile stress, elastic modulus and suture strength were 25.66 ± 4.42 MPa, 184.43 ± 23.27 MPa and 123.5 ± 2.69 gf, respectively), which were far superior to most previously reported biocorneal scaffolds reported so far. In addition, decellularized swim bladder collagen matrix scaffolds (SBCMs) supported the proliferation and adhesion of rabbit corneal epithelial cells (RCECs) and rabbit corneal stromal cells (RCSCs). Subcutaneous implantation experiments revealed that the scaffolds had a lower acute inflammatory response and better anti-degradation ability than human amniotic membranes used clinically. In summary, SBCMs have good biocompatibility, high light transmittance and excellent biomechanical properties, and can be used in the future to develop a novel generation of artificial corneas.