Abstract
Purpose:
To investigate adhesion properties and tissue reactions in an vitro model of nanofabricated membranes emulating the vitreous cortex.
Methods:
To create a synthetic vitreous cortex including emulation of the collagen fibrill network seen in vivo, we used solid elastomeric membranes composed of poly(glycerol- co-sebacic acid) (PGS) to support a layer of electrospun poly(epsilon-caprolactone) (PCL) nanofiber meshes. Electrospinning was performed for either 5, 10 or 15 min to create various thickness of PCL fiber mats on the PGS surface. Composite membranes were fused with adult porcine retinal explants with the fiber side facing the inner retina, and were kept under standard culture conditions for 5 days. Macroscopic inspection was performed to asses adhesion of composite membranes and retina and membrane-explant composites were compared with explants incubated under standard tissue culture conditions without added membrane. Cryosections of the specimens were stained with hematoxylin and eosin, immunohistochemical markers for photoreceptors and Müller glia (recoverin, NeuN, vimentin and glial acidic fibrillary protein (GFAP)). Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) labeling was performed to asses apoptosis.<br />
Results:
PGS membranes coated with PCL nanofibers electrospun for 5 minutes adhered poorly to the inner surface of the retina. 10 min specimens displayed excellent adhesion often covering the entire explant whereas 15 min counterparts adhered only at focal areas. 5 and 10 min specimens displayed an overall structure, apoptosis, and photoreceptor and Müller cell morphology comparable to controls. 15 min composite explants were thin and showed extensive photoreceptor cell death, disruption of the outer nuclear layer and atypical Müller cell morphology without the characteristic elongated vertical organization. Ganglion cell survival (NeuN) was most prominent in 10 min specimens whereas 5 min specimens and controls only displayed a few surviving NeuN labeled cells. In 15 min specimens, ganglion cells where not found<br />
Conclusions:
When emulating the vitreous cortex, the physical composition of nanofiber meshes are important for adhesion to the inner retina. Fiber mesh composition also has an impact on neuronal and glial survival in vitro. The results are important for research involving retinal transplantation as well as retinal prosthetics.