Abstract
Purpose :
To explore the feasibility of reconstructing and fabricating personalized biosynthetic keratoprosthesis using digital light processing (DLP) 3D bioprinting technique and N-acryloyl glycinamide/gelatin methacrylate-hybrid (PNG) bioink.
Methods :
Cornea-mimicking constructs based on synthetically cross-linked PNG bioink were produced by DLP 3D bioprinting. Its characteristics in terms of hydrophilicity, water content, nutrient permeability, stability, optical and mechanical properties were then tested for suitability as corneal replacement tissue. Cytocompatibility was evaluated with human corneal epithelial, stromal, and endothelial cell lines. In-vitro immune response was analyzed with human peripheral blood mononuclear cells by illumina RNA sequencing. In-vivo performance was assessed using an anterior lamellar keratoplasty (ALK) and intrastromal keratoplasty (ISK) model in New Zealand white rabbits.
Results :
DLP-bioprinting allows individualization of physical dimensions including thickness and curvature of the PNG keratoprosthesis. The material is superhydrophilic (contact angle 47°), has pre-specified water content (78%), good glucose permeabilization (diffusion coefficient: 2.11*10-6 cm2/s), high stability in PBS, bionic light transmittance (over 90%) and refractive index (≈1.375), and good structural strength (Young’s modulus≈0.2MPa). In-vitro evaluation displays that it supports the adhesion and viability (above 90%, over 7 days of cultivation) of corneal epithelial, stromal, and endothelial cells, while maintaining the phenotype and function of keratocytes (positive for Keratocan, CD34 and ALDH1A1). RNA sequencing results indicate that it activates type 2 immunity in macrophage, facilitates tissue regeneration and suppresses inflammation. In-vivo assessment in rabbits showed excellent surgical handling characteristics, and no adverse effects on the host corneal stroma, endothelium or other ocular tissues, although epithelialization was not achieved with the ALK model. Postoperative IOP, corneal sensitivity, and tear formation remains unaffected during the 1-month follow-up.
Conclusions :
Our DLP-bioprinted PNG keratoprosthesis is a novel, safe, and effective corneal graft alternative with personalisable physical dimensions which can potentially achieve better clinical outcome and address the current worldwide shortage of donor corneas.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.