Invited: A Magneto-chemical Approach to Target the Nervous System for Regeneration and Drug Delivery

Orit Shefi
Bar Ilan University, Israel

Controlling cell navigation, organization and growth has great importance in therapeutics. In this talk I will present our recent studies of magnetic-based manipulations for promoting cell regeneration, controlling the organization of the extracellular environment and for directing drug delivery to the nervous system.

As physical mechanical forces play a key role in neuronal morphogenesis, we use magnetic nanoparticles (MNPs) as mediators to apply forces locally on neurons throughout their migration and organization. Following incubation, the MNPs accumulated in the cells, turning the cells sensitive to magnetic stimulation. Applying magnetic fields with controlled magnetic flux densities leads to pre-designed cellular movement and to organized networks. Growing neurons loaded with MNPs under magnetic fields has affected the pattern of dendritic trees.

Moreover, we use the MNPs as a platform for drug delivery using magnetic targeting strategy aiming to enhance therapeutic efficiency by directing magnetic drug carriers specifically to selected cell populations. We conjugate covalently nerve growth factor that is an important protective factor to iron oxide nanoparticles (NGF-MNPs) and use controlled magnetic fields to deliver the NGF–MNP complexes to target sites. In order to actuate the magnetic fields a modular magnetic device was designed and fabricated. Cells that were plated homogenously in culture were differentiated selectively only in targeted sites out of the entire dish, restricted to areas above the magnetic `hot spots`. To examine the ability to guide the NGF-MNPs in vivo we examine two model systems; directing magnetic carriers within the sciatic nerve and directing MNPs to a mouse retina following an intravenously injection. These models present a ‘smart’ delivery system of biomolecules, together with integral guidance cues, that can cross the BBB and taget selectively the central nervous system presenting an emerging magneto-chemical approach for targeting the brain.

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