An in vitro assessment of the thermoreversible PLGA-PEG-PLGA copolymer: Implications for Descemet's membrane endothelial keratoplasty

Background To explore the use of a thermoreversible copolymer gel coating to prevent donor tissue scrolling in Descemet's membrane endothelial keratoplasty (DMEK). Methods PLGA-PEG-PLGA triblock copolymer was synthesised via ring opening polymerisation. Two formulations were fabricated and gelation properties characterised using rheological analyses. Endothelial cytotoxicity of the copolymer was assessed using a Trypan Blue exclusion assay. Thickness of the copolymer gel coating on the endothelial surface was analysed using anterior segment optical coherence tomography (OCT) (RTVue-100, Optovue Inc.). Gold nanoparticles were added to the copolymer to aid visualisation using OCT. Prevention of Descemet membrane donor scrolling was represented via a novel, in vitro, immersion of copolymer coated donor graft material. Results Two different formulations of PLGA-PEG-PLGA copolymer were successfully fabricated and the desired peak gelling temperature of 24 degrees C was achieved by polymer blending. Application of 20%, 30% and 40% (wt/vol) polymer concentrations resulted in a statistically significant increase in polymer thickness on the endothelium (p < 0.001). There was no detectable endothelial cytotoxicity. The polymer was easy to apply to the endothelium and prevented scrolling of the DMEK graft. Conclusion This PLGA-PEG-PLGA thermoreversible copolymer gel could be exploited as a therapeutic aid for preventing DMEK graft scrolling.