A Bioengineered Conjunctival Equivalent Using a Polycaprolactone Membrane Substrate for Ocular Transplantation

Abstract

Abstract: : Purpose: To investigate a bioengineered conjunctival tissue–equivalent using an ultra–thin polycaprolactone (PCL) membrane substrate for ocular transplantation. Methods: Ultra–thin PCL membranes 5µm in thickness were prepared by solvent casting and biaxial stretching. Rabbit conjunctival epithelial cells (CjE) were cultivated on NaOH–treated PCL membranes and untreated PCL membranes using serum–free media. The proliferative capacity of the CjE cells were analyzed using BrdU proliferation assays. Immunostaining with keratins 3, 4 and 19 and MUC5AC were performed. Conjunctival wounds created in rabbit eyes were transplanted with these conjunctival equivalents. Results: Atomic force microscopy of the biaxially stretched PCL membranes showed closely packed polymer molecules oriented in a uniaxial direction. PCL supported the attachment and proliferation of CjE cells, forming confluent stratified epithelial sheets. The BrdU assay of CjE cells cultivated on NaOH–treated PCL and untreated PCL, was 0.60+0.06 and 0.43+0.05 respectively. NaOH–treated membranes had greater cell attachment and proliferation. The membranes were easy to handle and suture, had a high strength–to–mass ratio, and were highly flexible, allowing it to mould to the ocular surface. CjE cells expressed keratins 4, 19, and MUC5AC, which was consistent with normal conjunctiva. Conclusions: Ultra–thin PCL membranes allowed the proliferation of conjunctival epithelial cells, forming stratified epithelial sheets. These membranes may potentially be a suitable scaffold for bioengineered conjunctival equivalents.

Keywords: conjunctiva • cornea: epithelium • transplantation