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Xiaokun Wang, Shoumyo Majumdar, Uri Soiberman, Jennifer H Elisseeff; Dual-layered Collagen Vitrigel Implant as Cornea-mimetic Substitute. Invest. Ophthalmol. Vis. Sci. 2018;59(9):1345. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To Engineer and evaluate dual-layered, collagen-based corneal substitute that incorporates tissue-derived microparticles to enhance mechanics, and a basement membrane to promote re-epithelialization.
The basement layer was achieved by exposing collagen solution to ammonia vapor to form gel. The stromal layer was prepared by mixing type I collagen solution with buffer solution containing cyclodextrin and tissue-derived microparticles. The mixture was carefully added to the prepared basement membrane gel, followed by slow vitrification at 5°C for 3 days and 40°C for 1 week. The rehydrated materials were tested for transparency in the visible spectrum, fibrillogenesis was visualized by second harmonic generation (SHG) microscopy. Biocompatibility was tested using ex vivo rabbit cornea organ culture, followed by in vivo implantation in rabbit partial lamellar keratoplasty (PLK) model.
Corneal substitutes were prepared at thicknesses up to 250 µm for rabbit corneal implantation. The incorporation of tissue-derived microparticles presented no significant influence on material transparency, while significantly enhanced suturability. SHG exhibited distinctive basement membrane layer and stromal layer, as basement membrane contained thin fibrous layer and 50 µm amorphous collagen, and stomal layer contained fibrous lamellaes. Biocompatibility of materials was verified through ex vivo migration studies on stromal layer and basement layer, respectively. H&E staining demonstrated basement layer supported epithelium multilayer formation as compared to the stromal layer. In a rabbit PLK model, the material was implanted using interrupted sutures in a pilot animal, and optical coherent tomography (OCT) demonstrated good stability and viability of the material. (Figure 1).
The dual-layered corneal mimetic material demonstrated good transparency, biomechanics and biocompatibility. The basement layer promoted epithelial cell migration and multilayer formation, and the stromal layer provided superior mechanical strength and stability. The pilot animal study results demonstrated a great potential of this material as a promising corneal substitute.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
Figure 1. (A) SHG image of the cross-section of the dual-layered implant. Ex vivo migration study showed basement membrane layer (B) supported multilayer formation as compared to stromal layer (C); (D) in vivo implantation in a rabbit model
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