Abstract
Abstract: :
Purpose: Current methods to promote healing of persistent corneal wounds include limbal allograft and ex vivo expansion of stem cells on amniotic membrane. This cell scaffold has many technical challenges. An alternative cell transplant device based on Polydimethylsiloxane (PDMS) contact design was evaluated. Methods: A highly O2 permeable polymer, PDMS, which is commercially available as Syglard® 184 (Dow Corning), was used to fabricate contacts. We used a previously described human corneal epithelial cell line (Araki–Saski et al., IOVS 36(3):614, 1995) to test PDMS cell growth and transfer characteristics to plastic and damaged pig cornea. Growth on PDMS coated 6–well plates was compared to growth on standard tissue culture 6–well plates. We added 5,000 cells per cm2 to each well. Cells were trypsinized and counted at 2, 5 and 9 days after seeding to compare growth characteristics. To test transfer, PDMS disks with epithelial cells grown to confluence were placed into a 6–well tissue culture flask cell–side down. After 1, 2 or 3 days plastic and PDMS surfaces were trypsinized and released cells were counted to quantify transfer. In addition, cell–coated PDMS contacts were applied to a de–epitheliazed pig cornea. CellTracker® Green CMFDA (Molecular Probes) was used to identify cells originating from the cell–coated PDMS contact. Pig corneas were imaged by fluorescence microscopy at days 1, 2 and 3. Results: Corneal epithelium grew equally well on PDMS and standard tissue culture plastic (N=12). Cells reached a confluent density (100,000 cells/cm2) on both surfaces after 5 days, when initially seeded at 5,000 cells/cm2. Within 2 days 60% of viable cells transferred from PDMS onto the plastic (N=6). Transfer to damaged pig corneas was also observed. Conclusions: This extracorporeal PDMS contact shows promise as an alternative means to prepare and deliver corneal stem cells to a damaged cornea.
Keywords: contact lens • wound healing • cornea: epithelium