Tuning Neuronal Circuit Formation in 3D Polymeric Scaffolds by Introducing Graphene at the Bio/Material Interface

Abstract

2D cultures are useful platforms allowing studies of the fundamental mechanisms governing neuron and synapse functions. Yet, such models are limited when exploring changes in network dynamics due to 3D‐space topologies. 3D platforms fill this gap and favor investigating topologies closer to the real brain organization. Graphene, an atom‐thick layer of carbon, possesses remarkable properties and since its discovery is considered a highly promising material in neuroscience developments. Here, elastomeric 3D platforms endowed with graphene cues are exploited to modulate neuronal circuits when interfaced to graphene in 3D topology. Ex vivo neuronal networks are successfully reconstructed within 3D scaffolds, with and without graphene, characterized by comparable size and morphology. By confocal microscopy and live imaging, the 3D architecture of synaptic networks is documented to sustain a high rate of bursting in 3D scaffolds, an activity further increased by graphene interfacing. Changes are reported in the excitation/inhibition ratio, potentially following 3D‐graphene interfacing. A hypothesis is thus proposed, where the combination of synapse formation under 3D architecture and graphene interfaces affects the maturation of GABAergic inhibition. This will tune the balance between hyperpolarizing and depolarizing responses, potentially contributing to network synchronization in the absence of changes in GABAergic phenotype expression.

Bidirectional Modulation of Neuronal Cells Electrical and Mechanical Properties Through Pristine and Functionalized Graphene Substrates

“…Even though several reports have already demonstrated the successful development of hippocampal cell cultures interfaced with graphene substrates ( Tang et al, 2013 ; Fabbro et al, 2016 ; Kitko et al, 2018 ; Pampaloni et al, 2018a ; Rauti et al, 2020b ), this aspect has not been evaluated on chemically functionalized graphene yet. To explore the potential effects of graphene and its chemical functionalization on cell development and network composition, we cultured primary hippocampal neurons on both pSLG and fSLG supports.…”

Is Graphene Shortening the Path toward Spinal Cord Regeneration?

“…Different studies have highlighted the favorable response of 3D graphene-based porous scaffolds to modulate the behavior of CNS cellular components. For example, cultured hippocampal neuronal and glia cells effectively colonized the pores of a 3D graphene construct in vitro , leading to the recreation of complex neural networks with a wide range of active synaptic connections in which the high rate of spontaneous bursts was associated with the interference of graphene with the maturation of GABAergic inhibition . Effectively, neuronal circuit dynamics was influenced by the establishment of 3D neuron–graphene interactions responsible not only for increasing the synchronization of the synaptic activity, including transitions between highly and moderately synchronized regimes, but also for promoting the interconnectivity among active neurons by inciting neurite elongation to cover long distances through and cross the pores .…”

“…For example, cultured hippocampal neuronal and glia cells effectively colonized the pores of a 3D graphene construct in vitro , leading to the recreation of complex neural networks with a wide range of active synaptic connections in which the high rate of spontaneous bursts was associated with the interference of graphene with the maturation of GABAergic inhibition. 279 Effectively, neuronal circuit dynamics was influenced by the establishment of 3D neuron–graphene interactions responsible not only for increasing the synchronization of the synaptic activity, including transitions between highly and moderately synchronized regimes, but also for promoting the interconnectivity among active neurons by inciting neurite elongation to cover long distances through and cross the pores. 280 3D porous structures fabricated by advanced CVD modalities could even modulate neural cell behavior in vitro according to rigorous geometrical disposition of graphene building blocks, including their skeleton dimension and orientation angle, as well as pore size.…”

Graphene‐Based Nanomaterials for Neuroengineering: Recent Advances and Future Prospective

“…[44] In particular, GR ability to be combined with a variety of other bioactive structures opens to novel and original approaches to design materials for neuroengineering applications. Although GR-based materials have been widely utilized to fabricate films [45,46] or 3D scaffolds [47,48] able to sustain neuronal development and nerve fibers regrowth, there are ongoing studies in order to extend the versatility and functionality of GR and its chemical derivatives for neuronal regenerative medicine. The positive role of GR and its derivatives has also been confirmed in electrical stimulation of neuronal cells for the growth, differentiation, and the development of neuronal lineage cells.…”