FIGURE 1.

Strategies for targeted delivery to the peripheral nervous system. (I) Direct placement of a bioengineered nerve conduit in the presence of breached perineurial and blood-nerve (endoneurial) barriers. (II) Administration of anesthetic or analgesic by injection at or outside the epineurium (a), outside the perineurium (b), or within a fascicle (c). Administration of a peptide or protein requires localized, transient disruption of perineurial and blood-nerve barriers. (III) Presynaptic uptake and retrograde trafficking at peripheral nerve terminals results in delivery of cargo along individual axons within a fascicle. (IV) Endothelial targeting of systemically administered nanoparticles can preferentially target the endoneurial vasculature.