Alginate Hydrogels as Injectable Drug Delivery Vehicles for Optic Neuropathy Treatment

Abstract

Optic neuropathy is the loss of visual acuity following damage to the optic nerve (ON). Traumatic optic neuropathy (TON) occurs when the optic nerve is injured following blunt or penetrating trauma to either the head or eye. Current management options for TON include the systemic delivery of corticosteroids and surgical decompression of the optic nerve; however, neither option alleviates the generation of reactive oxygen species (ROS) which are responsible for downstream damage to the ON. Addressing this limitation, an injectable alginate hydrogel system was developed to act as a drug delivery vehicle for methylene blue (MB), a confirmed ROS scavenger and neuroprotective agent. This MB-loaded polymeric scaffold has the ability to be injected as a liquid and rapidly form a gel around the optic nerve following the primary injury, allowing for the prolonged release of MB. The MB-loaded alginate hydrogels demonstrated minimal cytotoxicity to human retinal pigment epithelial (ARPE-19) cells and facilitated gradual MB release over 12 days. Additionally, the MB concentrations displayed a high degree of ROS scavenging after release from the alginate hydrogels, suggesting our approach may be successful in reducing ROS levels following ON injury.