Ultra-thin, Strong and Cell-Adhesive Agarose-Based Membranes Engineered as Substrates for Corneal Endothelial Cells

We aimed to bioengineer a scaffold that can facilitate the transplantation of corneal endothelial cells (CEC), given the global shortage of cadaveric donor tissues. Although agarose (A) has outstanding biocompatibility and mechanical properties, it natively does not permit cell adhesion. In this study, agarose was modified with different attachment signals: GRGD (giving AR as product), lysine (AK), poly lysine (AP), and fish-derived gelatin (AG). Samples with varying conjugation ratios were prepared. All products formed bulk hydrogels, which were then collapsed into ultrathin membranes in a controlled environment. Membranes were evaluated for their ability to support attachment of various cell types. Cells, however, preferred the AG series of membrane. Notably, primary rabbit CEC remained attached and viable for >= 4 weeks. The cells also stained positive for CD166, ZO-1 and Na+/K+ ATPase, indicative of function. The hydrated AG membranes allowed >96% transmittance of visible light. The membranes were typically similar to 15 mu m thick and did not swell significantly after immersion in PBS. Tensile strength was 49-60 MPa, while young's modulus was 525-596 MPa. This membrane thus offers great promise as a scaffold for CEC during endothelial keratoplasty.