Single-Sided Dual-Functional MPC-HEMA Coating for DMEK Grafts to Achieve Fluid-Barrier/Anti-Fouling Performance and Native Matrix Preservation

Corneal endothelial dysfunction is a leading cause of global blindness. Descemet's membrane endothelial keratoplasty (DMEK) is an advanced treatment, offering minimal invasiveness, rapid visual recovery, and low risk of immune rejection. However, its clinical application remains limited because the donor graft is extremely thin (about 15 μm), which makes it vulnerable to scrolling and aqueous humor leakage during surgery. To address these issues, this study developed a unilaterally functionalized coating for donor grafts using hydroxyethyl methacrylate (HEMA) and 2-methacryloyloxyethyl phosphorylcholine (MPC). The coating is designed with dual functionality: the MPC‑modified side forms a hydration layer that blocks non‑specific protein adsorption and aqueous penetration through steric hindrance, while the HEMA component provides mechanical stability to reduce graft scrolling and displacement during surgery. The opposite side of the graft retains its natural matrix structure to support human corneal endothelial cell (HCEC) adhesion and function. Two photo-crosslinking strategies were compared: bulk copolymerization of MPC with HEMA (p(MPC-co-HEMA)) and surface grafting of MPC onto p(HEMA) (p(MPC-graft-HEMA)). Their physicochemical properties, antifouling performance, and clinical operability were evaluated to select the optimal coating method. The developed materials demonstrated stable mechanical properties, good biocompatibility, and strong resistance to protein and bacterial adhesion. In summary, this unilaterally functionalized coating offers a practical solution to the key challenges of DMEK surgery, showing significant potential to improve surgical success and promote broader clinical application.