On-demand release of the small-molecule TrkB agonist improves neuron-Schwann cell interactions

Various extracellular factors jointly control a wide variety of neuronal functions. On-demand delivery system provides a platform to integrate multiple signals in one intervention. In this study, we fabricated an electrically controlled drug delivery nanocomposite composed of graphene oxide (GO) deposited inside a poly(3,4-ethylenedioxythiophene) (PEDOT) film. 7,8-dihydroxyflavone (7,8-DHF) was loaded on GO via π-π stacking and consequentially encapsulated into the electrochemically active film during deposition, which was followed by a Dopamine-graft-Chitosan (CD) coating to improve the biocompatibility. 7,8-DHF was released in response to voltage stimulation and the dosage was adjusted by altering the magnitude of stimulation. The on-demand delivery system promoted dorsal root ganglion (DRG) neurite outgrowth, Schwann cell migration, myelination, and synapse transmission. Neuronal mitochondrial biogenesis was enhanced as determined by immunofluorescence staining and gene expression of HSP60, a mitochondrial localized quality control protein. Therefore, we provided an on-demand delivery platform of temporal control and dosage flexibility to integrate multiple signals in the modulation of neural behaviors and functions.