Neuro-Nanotechnology—Graphene-Based Materials to Target Network Excitability

The growing interest in utilizing graphene and graphene-based materials (GBMs) for applications such as drug and gene delivery, biomedical imaging, and diagnostic biosensors in the central nervous system has spurred neuroscientists to investigate the impact of GBMs on primary neural cells. Our focus has centered on characterizing the interactions of graphene nano-sheets within the central nervous system and exploring the potential of 2D graphene-based supports as biocompatible scaffolds for neurological applications. The goal is to leverage the conductive properties of graphene to regulate neural network activity closely associated with these structures. Our findings reveal that while exposure to graphene materials does not compromise neuronal and glial viability or blood-brain-barrier permeability, it does exert notable effects on neuronal and glial physiology. These effects encompass synaptic activity, intracellular Ca²⁺ dynamics, and astrocyte glutamate uptake. The results suggest that graphene oxide may play a protective role in neuro-pathologies characterized by hyperexcitability. Interestingly, our ongoing investigation is displaying a very high biocompatibility of graphene flakes with microglia cells, thus encouraging the future application of GBMs in neuroscience.<br/>Additionally, we delved into the molecular and cellular mechanisms governing the interaction between 2D graphene-based supports and primary neurons and astrocytes. This exploration aims to evaluate the feasibility of employing these materials as flexible, transparent, and implantable devices for stimulating and triggering neuron excitability. We treated monolayer graphene, grown via chemical vapor deposition (CVD), with remote hydrogen plasma to demonstrate that hydrogenated graphene enhances cell-to-cell communication in primary cortical neurons compared to pristine graphene. This enhancement manifests through increased excitatory synaptic connections and a doubled frequency of miniature excitatory postsynaptic currents. Once again, there is no sign of glial reactivity when hydrogenated graphene is interfaced with primary astrocytes. Furthermore, we successfully modified P3HB, an amorphous biocompatible polymer, for neuronal interfacing by incorporating graphene oxide nano-platelets into the polymer structure. Finally, we are investigating laser-induced graphene 2D supports as their preparation is less time consuming and cheaper compared to CVD-graphene. These investigations indicate that wettability, more than electrical conductivity, is the crucial parameter to control when designing neural interfaces.