Few-layered graphene increases the response of nociceptive neurons to irritant stimuli.

The unique properties of few-layered graphene (FLG) make it interesting for a variety of applications, including biomedical applications, such as tissue engineering and drug delivery. Although different studies focus on applications in the central nervous system, its interaction with the peripheral nervous system has been so far overlooked. Here, we investigated the effects of exposure to colloidal dispersions of FLG on the sensory neurons of the rat dorsal root ganglia (DRG). We found that the FLG flakes were actively internalized by sensory neurons, accumulated in large intracellular vesicles, and possibly degraded over time, without major toxicological concerns, as neuronal viability, morphology, protein content, and basic electrical properties of DRG neurons were preserved. Interestingly, in our electrophysiological investigation under noxious stimuli, we observed an increased functional response upon FLG treatment of the nociceptive subpopulation of DRG neurons in response to irritants specific for chemoreceptors TRPV1 and TRPA1. The observed effects of FLG on DRG neurons may open-up novel opportunities for applications of these materials in specific disease models.