Abstract
Purpose :
To develop an in vitro millifluidic screening platform for evaluating the biodegradation of ocular inserts and their toxicity on human corneal epithelial cells (HCECs).
Methods :
Gelatin Methacrylate (GelMA) ocular inserts with polyvinyl alcohol (PVA) (10% GelMA 7.5% PVA), a wetting agent, were placed inside a custom-designed millifluidic device and tested over 24 hours at 37oC. A solution of up to 200 μg/mL of matrix metalloproteinases 9 (MMP9) in phosphate-buffered saline was flown at a rate of 300 μL/mL for each channel. The MMP9 was added to facilitate the degradation of the inserts. The biodegradation of the ocular inserts was quantified visually using a computational image analysis pipeline. The eluates containing the degradation products were collected and the amount of PVA released was measured using a colorimetric assay. The toxicity of the eluates to HCECs inside the millifluidic device was determined using alamarBlueTM assays after 24 hours of treatment, and their effects on HCEC tight junction integrity were assessed by immunostaining for zonula occludens 1 (ZO-1) protein.
Results :
The computational analysis measured the degradation profile of the inserts every minute. The biodegradation of the GelMA-PVA inserts was greater when treated with MMP9 than without (p<0.05). In addition, the amount of PVA released was also higher in the MMP9 condition (p<0.05). The eluates collected from all conditions were non-toxic to HCECs, and there was no apparent disruption of the tight junction protein ZO-1.
Conclusions :
This novel screening platform was able to quantify GelMA biodegradation, while enabling simultaneous measurements of therapeutic release and HCEC viability. HCECs integrated into this device were viable and displayed normal ZO-1 cellular localization, indicating that this platform can be used to screen other hydrogel formulations containing therapeutics and evaluate their toxicity to HCECs.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.