Magnetic guidance of ferrofluidic nanoparticles in an in vitro model of intraocularretinal repair

Abstract

Agarose gel at a concentration of 0.6% was used to simulate the vitreous body ofthe eye during the infusion of a ferrofluid and the subsequent magneticconcentration of it onto a surrogate retinal surface. The 10 nm Fe3O4particles in the ferrofluid served to mimic the cobalt particles in a siliconemagnetic fluid that is being developed for use as a tamponading agent inmagnetic fluid therapies designed to alleviate retinal detachments andother types of retinopathy. Magnetically guided interstitial diffusion of thenanoparticles through up to 20 mm of the gel over periods of 72 h wasshown to be possible, thus demonstrating that essentially all points on theretinal surface are reachable from elsewhere in the ocular interior. Thenanodynamics of the magnetic and viscous forces at work on the particlesduring movement through the gel are discussed; in particular the diffusionspeeds of the particles are estimated and compared with observations.