Abstract
Purpose :
Corneal scarring resulting from improper healing of the cornea is the third most common cause of blindness worldwide. Current methods for aiding corneal wound healing can be expensive, difficult to source, or have low bioavailability. Plano lenses have been used as bandage contact lenses (BCLs) to reduce pain and prevent the corneal surface from further damage after injury, but they have limited therapeutic effects. By conjugating hyaluronic acid (HA) onto the surface of the contact lens, it is thought that a BCL capable of improving corneal wound healing and minimizing scarring can be produced.
Methods :
Model pHEMA-co-TRIS lenses were synthesized using free radical polymerization. Surface acrylation was done in the presence of the catalyst diisopropylethylamine (DIPEA). The small molecules diethylamino ethanethiol (DEAET) and dimethylamino ethanethiol (DMAET) were tethered using a thiol-ene "click" reaction. The successful acrylation and conjugation of the small molecules were confirmed through FTIR. Quantification of HA was performed using radiolabelled HA and subsequent gamma counting. In vitro cell studies using human corneal epithelial cells (HCECs) were conducted to determine cytotoxicity using MTT and LIVE/DEAD.
Results :
FTIR showed the successful acrylation and conjugation on the lens surface. DMAET and DEAET modified lenses showed significantly higher (p <0.001) HA binding compared to model pHEMA-co-TRIS controls at all time points shown in Figure 1. The modified lenses improved release kinetics preventing an initial burst release and showed consistent release when unloaded and reloaded with HA. The contact angle was significantly decreased (p <0.05) for the modified model lenses with HA without affecting the equilibrium water content and optical transparency. Finally, the modified model lenses did not exhibit any cytotoxicity in vitro with HCECs.
Conclusions :
Our results show that we were able to produce a lens capable of surface binding HA. The lens was able to bind more HA compared to unmodified controls while providing a sustained release of HA and excellent rebinding kinetics. The lenses were well tolerated based on in vitro cell studies.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.