Abstract
Purpose :
To address the corneal donor shortage for Anterior Lamellar Keratoplasty (ALK) procedures we present optical and rheological properties of the individual materials Gelatin Methacryloyl (GelMA) and Silk Fibroin Methacrylate (SilMA) and their combination to produce an acellular scaffold as a graft through a 3D pneumatic extrusion bioprinting process.
Methods :
GelMA and SilMA have shown positive characteristics as base materials for bioinks due to their low cytotoxicity, cellular attachment motifs (GelMA), and high mechanical strength (SilMA). The photocrosslinked combination of those materials provides a hydrogel scaffold for transplantation purposes. Along with the base inks, a composite ink of 1:1 GelMA:SilMA was evaluated to determine printability and functionality. The absorbances of all ink materials were evaluated between 300 nm and 800 nm. Transmittances and refractive indices were calculated. Statistical analyses were performed with one way ANOVA and Tukey-Kramer post hoc test to determine the differences between the bioink materials. Rheological properties (viscosity, shear rate) of the materials GelMA, SilMA, and the composite GelMA/SilMA, were also evaluated.
Results :
The rheological evaluation to determine the printability showed a shear thinning behavior for all inks (Figure 1) with SilMA showing the highest viscosity, GelMA the lowest, and the mixture in between. The optical evaluation was done over a spectrum of 300 nm to 800 nm with photospectrometric measurement of the absorbance. Transmittance (Figure 2) and refractive index were calculated. With DI water as the reference, there was not a significant difference in absorbance between DI-water and GelMA, and GelMA and GelMA/SilMA over the entire spectrum. DI-water was significantly different than GelMA/SilMA and SilMA was significantly different than GelMA/SilMA, GelMA, and DI-water with p<0.05.
Conclusions :
The significantly higher absorption of SilMA could be attributed to the β-sheet formation in the silk structure. The transmittance of the ink mixture is in the range of the natural cornea (80-90%). Combining the mechanical properties of SilMA with the optical properties of GelMA in the composite demonstrates potential for bioprinting for ocular applications.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.