Abstract
Purpose :
The use of amniotic membrane to heal corneal defects is associated with a host of storage, processing, and testing expenses. Luna is developing an ocular biomaterial (BIOcular™) that mimics these healing properties using a nanofiber-reinforced hydrogel applied without sutures. The optical, mechanical, and biological properties of BIOcular™ prototypes were evaluated with in vitro and ex vivo techniques.
Methods :
Luna developed an electrospraying/spinning system for fabrication. Nanofiber alignment was evaluated using the FibrilTool ImageJ plugin and SEM images. Primary human corneal epithelial cells (HCECs) were cultured for cytocompatibility testing using the lactate dehydrogenase assay. UV-Vis spectroscopy was used to quantify sample transparency at 550 nm, and an Abbe Refractometer was used to determine the refractive index. Sample degradation was monitored in simulated tear solution. Photochemical tissue bonding (PTB) using an Iridix OcuLight GL laser (532 nm, 0.25 W) was investigated for sutureless adhesion using 0.01-0.1% rose bengal.
Results :
Luna’s unique dual electrospinning/spraying setup was used for pilot-scale production. Cytocompatibility tests with HCECs indicated dressings were nontoxic as compared to low density polyethylene positive controls. UV-Vis spectroscopy showed >85% transmission of 550 nm light for a hydrated dressing, and the refractive index was 1.335. Using image processing of SEM images, Luna confirmed alignment of the nanofiber-reinforcing layers and demonstrated control over the degree of alignment during production, with final dressings having an anisotropy value >0.2. Luna utilized 532 nm light to adhere the dressing to the surface of an excised rabbit eyeball using PTB with rose bengal. Rose bengal was incorporated in the hydrogel component of the dressing and achieved adhesion to the surface with no cytotoxic effect to HCECs at 0.05% wt/vol. Luna demonstrated controlled degradation (5 min to 4 wk) in simulated ocular fluids by altering hydrogel crosslinking.
Conclusions :
Luna successfully demonstrated the feasibility of this ocular biomaterial to stimulate corneal surface healing. The dressing was found to have a refractive index of 1.335, transmission of 85% for 550 nm light, and to be cytocompatible with primary human corneal epithelial cells. In vivo studies are ongoing in a rabbit model for corneal defects to demonstrate improved healing and establish photochemical tissue bonding in vivo.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.