Abstract
Purpose :
To develop a cost-effective and scalable 3D printing method and novel bioinks to fabricate contact lenses.
Methods :
The bioink formulations consisted of GelMA (gelatin methacrylate), LAP (Lithium phenyl-2,4,6-trimethylbenzoylphosphinate), and a yellow food-grade dye. The dye minimizes unwanted light leakage during the photopolymerization process. A commercial mSLA (masked stereolithography) printer, the Photon Mono X (AnyCubic, Shenzhen), was retrofitted with a custom temperature and humidity control kit. The printing process was performed at 40 oC and 90% humidity to ensure that the GelMA remained at a liquid state and to prevent the bioink from drying out, respectively. A set of matrix cubes of varying sizes with holes was used as a standard control. Images of the cubes were taken with a camera, top-down and side-review, analyzed with the ImageJ software and compared with the original CAD designs to derive an overall print quality score. Two print variables, exposure time (5 s to 40 s) and yellow dye concentration (1 – 7%), were analyzed in this study.
Results :
The best resolution with the highest print scores were obtained at either 5% yellow dye concentration and 30 seconds exposure time, or 3% yellow dye concentration and 20 seconds exposure time. There was an overall optimal range for both print times (20 - 30 s) and yellow dye concentration (3 - 5%). Values above or below this critical value resulted in lower print quality scores of the standard cubes. A prototype contact lens with a 200 µm thickness was able to be 3D printed using the developed print methods and parameters, with a total print time of approximately 20 minutes. Approximately 28 contact lenses can be printed at the same time using the 3D printer. However, the surface and edges of the 3D printed contact lens were still visually very rough.
Conclusions :
The current study demonstrated that a low-cost commercial 3D mSLA printer can be used to fabricate model contact lenses using a hydrogel material. Still, further work is necessary to improve the print quality for fabricating ultra-thin devices such as contact lenses. Future work will use this 3D printing method to fabricate contact lenses for drug delivery.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.