Carbon Nanotubes, Directly Grown on Supporting Surfaces, Improve Neuronal Activity in Hippocampal Neuronal Networks

Abstract

Carbon nanotube (CNT)-modified surfaces unequivocally demonstrate their biocompatibility and ability to boost the electrical activity of neuronal cells cultured on them. Reasons for this effect are still under debate. However, the intimate contact at the membrane level between these thready nanostructures and cells, in combination with their unique electrical properties, seems to play an important role. The entire existing literature exploiting the effect of CNTs on modulating cellular behavior deals with cell cultures grown on purified multiwalled carbon nanotubes (MWNTs) deposited on a supporting surface via drop-casting or mechanical entrapment. Here, for the first time, it is demonstrated that CNTs directly grown on a supporting silicon surface by a chemical vapor deposition (CVD)-assisted technique have the same effect. It is shown that primary neuronal cells developed above a carpet of CVD CNTs form a healthy and functional network. The resulting neuronal network shows increased electrical activity when compared to a similar network developed on a control glass surface. The low cost and high versatility of the here presented CVD-based synthesis process, together with the possibility to create on supporting substrate patterns of any arbitrary shape of CNTs, open up new opportunities for brain-machine interfaces or neuroprosthetic devices.

Transparent carbon nanotubes promote the outgrowth of enthorino‐dentate projections in lesioned organ slice cultures

“…CNTs carpets have been since long characterized as platforms enriched with nano‐scaled topology able to support neural cultures development, and their effects on cultured hippocampal primary cells are well described (Cellot et al, 2009, 2011; Lovat et al, 2005). Anyway, being the result of a novel fabrication process, our first concern was to understand if the new tCNTs carpets were biocompatible and able to sustain the development of healthy and functional neural networks, potentiating the emerging synaptic activity in respect to Control cultures, as reported for opaque CNTs interfaces (Cellot et al, 2011; Lovat et al, 2005; Mazzatenta et al, 2007; Rago et al, 2019). To this aim, we compared cultured dissociated primary neurons from rat hippocampus interfaced to tCNTs‐decorated substrates with glass supported Controls.…”

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

“…Besides, 3D platforms, when compared to 2D ones, were shown to impact neuronal differentiation,9,43,44 cell and axonal growth,45,46 circuit functional organization and synaptic network synchronization 2. Further engineering of 3D scaffolds into CNS regenerative interfaces may be pursued by the use of nanomaterials, such as carbon‐based ones, to improve the device's electrical conductivity and to favor the development of excitable tissue 7,22,47–49. Here, we exploit elastomeric 3D platforms to investigate the impact on network dynamics of posing at the interface few‐layer graphene, known to affect cell signaling when supporting 2D cultures 8.…”

“…Decorating the elastomeric structure with nanomaterials exploits the scaffold properties at the interface, for example, guiding growth and adhesion of axons to the device or implementing the 3D construct of active components, such as electrically conductive pathways 4. Also, apart MWCNTs,2,5–7 many other carbon‐based nanomaterials as, for example, graphene,8 may be used. This will provide artificial biomimetic cues able to affect synapse formation or neuronal information processing through the physical interactions of the nanomaterial with the biological environment.…”

Interfacing Neurons with Nanostructured Electrodes Modulates Synaptic Circuit Features

“…After 10 min of recording of sustained spontaneous synaptic activity (Figure 6c), a cocktail of synaptic receptor antagonists, containing APV (25 × 10 −6 m), BIC (10 × 10 −6 m), and CNQX (10 × 10 −6 m), was applied to functionally disconnect neurons from the network activity. [48,49] This condition allowed testing the efficacy of electrical stimuli delivered via the Au substrates in directly depolarizing the monitored neurons, eventually inducing a burst of action potentials. Figure 6d shows such recordings where five biphasic low-voltage steps, repeated three times (Figure 6b, lower left sketch), were delivered either via Au-Flat or Au-NWs electrodes.…”