Direct Ink Writing of an Orthogonal Collagen-Based Membrane for Sutureless Corneal Repair

The native corneal stroma is composed of highly organized collagen lamellae with alternating orientations. However, reconstructing this complex architecture while avoiding suture-associated complications remains a major challenge in corneal repair. Herein, building on the previously established pseudo-polyrotaxane and collagen (PPR-COL) system, an orthogonally structured PPR-COL membrane fabricated via direct ink writing (DIW) was integrated with a bioadhesive layer composed of gelatin methacryloyl and oxidized hyaluronic acid for sutureless fixation. The concentration-dependent rheological behavior and printing performance of the PPR-COL inks were systematically investigated to determine the optimal formulation that balanced extrusion capability with structural fidelity. The chemical structure and morphology of the bioadhesive layer were characterized, and its maximum tissue adhesion strength reached 95.1 kPa. Subsequent in vitro experiments confirmed the cytocompatibility of the PPR-COL membrane and determined the optimal photo-crosslinking duration. In a rabbit lamellar keratoplasty model, the printed membrane combined with the bioadhesive fixation promoted the repair of the corneal epithelium and stroma within 28 days and maintained favorable outcomes throughout a 180-day follow-up period, as demonstrated by slit-lamp examination, optical coherence tomography, histological analysis, corneal topography, biomechanical assessment, and in vivo confocal microscopy. Collectively, this study presents an integrated strategy for the fabrication and sutureless fixation of collagen-based membranes, providing a potential approach for corneal stromal reconstruction. STATEMENT OF SIGNIFICANCE: A bioinspired collagen-based corneal membrane was fabricated by direct ink writing using a previously established pseudopolyrotaxane-collagen bioink. The printed membrane reproduced the orthogonal lamellar architecture of the native corneal stroma, providing a structurally organized collagen-based substitute for corneal stromal repair. Moreover, an oxidized hyaluronic acid/GelMA bioadhesive interface was integrated with the printed membrane to achieve stable sutureless fixation to the host corneal bed. In vivo lamellar keratoplasty demonstrated favorable tissue integration, corneal reconstruction, and long-term biocompatibility. This work provides an integrated structural and interfacial design strategy for developing biomimetic collagen-based corneal substitutes and advancing minimally invasive corneal repair.