Photo‐ablation of human vitreous opacities by light‐induced vapor nanobubbles

Abstract

AbstractPurposeFloaters are collagen aggregates that can form in the vitreous of the eye due to structural changes and which cast shadows on the retina. Current therapies are based on laser treatment with an yttrium garnet laser (YAG) or vitrectomy (i.e. the replacement of the vitreous by a saline solution) but most of the time, floaters are left untreated. Besides, the efficacy of YAG laser treatment is still controversial and vitrectomy can be associated with important side effects (cataract formation, endophthalmitis).MethodsIn this work we propose a nanotechnology‐based approach for the treatment of floaters using the plasmon properties of gold nanoparticles (AuNPs). When exposed to pulsed‐laser light (typically a nanosecond laser), AuNPs able to bind floaters, heat up and generate vapour nanobubbles (VNBs) due to the evaporation of the surrounding water. These VNBs will then burst providing sufficient mechanical energy to fragment floaters.ResultsTo maximize the probability of AuNPs to reach and bind floaters after intravitreal injection, we coated them with hyaluronic acid (HA‐AuNPs) and observed they had a better diffusion in vitreous and could bind and fragment collagen I fibers and human floaters obtained from patients. Since smaller AuNPs have a higher threshold to generate VNBs we hypothesized smaller HA‐AuNPs (10 nm), would be able to clusterize on the floaters to locally decrease the threshold to generate VNBs preserving the surrounding vitreous and ocular tissues from being damaged. With smaller particles we were able to destroy human vitreous opacities, in a fast and reproductive manner.ConclusionOur strategy can effectively and rapidly destroy floaters by using lower energy levels compared to current YAG therapy and paves the way for the use of pulsed‐lasers and nanotechnologies in the posterior segment of the eye.