Nanomedicine and graphene-based materials: advanced technologies for potential treatments of diseases in the developing nervous system

Abstract: The interest in graphene-based nanomaterials (GBNs) application in nanomedicine, in particular in neurology, steadily increased in the last decades. GBNs peculiar physical–chemical properties allow the design of innovative therapeutic tools able to manipulate biological structures with subcellular resolution. In this review, we report GBNs applications to the central nervous system (CNS) when these nanomaterials are engineered as potential therapeutics to treat brain pathologies, with a focus on those of the pediatric age. We revise the state-of-the art studies addressing the impact of GBNs in the CNS, showing that the design of GBNs with different dimensions and chemical compositions or the use of specific administration routes and doses can limit unwanted side effects, exploiting GBNs efficacy in therapeutic approaches. These features favor the development of GBNs-based multifunctional devices that may find applications in the field of precision medicine for the treatment of disorders in the developing CNS. In this framework, we address the suitability of GBNs to become successful therapeutic tools, such as drug nano-delivery vectors when being chemically decorated with pharmaceutical agents and/or other molecules to obtain a high specific targeting of the diseased area and to achieve a controlled release of active molecules. Impact: The translational potential of graphene-based nanomaterials (GBNs) can be used for the design of novel therapeutic approaches to treat pathologies affecting the brain with a focus on the pediatric age.GBNs can be chemically decorated with pharmaceutical agents and molecules to obtain a highly specific targeting of the diseased site and a controlled drug release.The type of GBNs, the selected functionalization, the dose, and the way of administration are factors that should be considered to potentiate the therapeutic efficacy of GBNs, limiting possible side effects.GBNs-based multifunctional devices might find applications in the precision medicine and theranostics fields

Bridging pro-inflammatory signals, synaptic transmission and protection in spinal explants in vitro

Multiple sclerosis is characterized by tissue atrophy involving the brain and the spinal cord, where reactive inflammation contributes to the neurodegenerative processes. Recently, the presence of synapse alterations induced by the inflammatory responses was suggested by experimental and clinical observations, in experimental autoimmune encephalomyelitis mouse model and in patients, respectively. Further knowledge on the interplay between pro-inflammatory agents, neuroglia and synaptic dysfunction is crucial to the design of unconventional protective molecules. Here we report the effects, on spinal cord circuits, of a cytokine cocktail that partly mimics the signature of T lymphocytes sub population Th1. In embryonic mouse spinal organ-cultures, containing neuronal cells and neuroglia, cytokines induced inflammatory responses accompanied by a significant increase in spontaneous synaptic activity. We suggest that cytokines specifically altered signal integration in spinal networks by speeding the decay of GABAA responses. This hypothesis is supported by the finding that synapse protection by a non-peptidic NGF mimetic molecule prevented both the changes in the time course of GABA events and in network activity that were left unchanged by the cytokine production from astrocytes and microglia present in the cultured tissue. In conclusion, we developed an important tool for the study of synaptic alterations induced by inflammation, that takes into account the role of neuronal and not neuronal resident cells

Carbon based substrates for interfacing neurons: Comparing pristine with functionalized carbon nanotubes effects on cultured neuronal networks

Pristine (as prepared) carbon nanotube (CNT) based substrates have been widely used to grow and interface neurons in culture. Nerve cells normally differentiate on CNTs and the synaptic networks, newly formed at the interface with this material, usually show an improved robustness in signal transfer. However manipulation of pristine CNTs is often prevented by their low dispersibility and tendency to aggregate in most solvents. This issue can be at least partially solved by adding solubilizing groups to the surface of CNT, which also helps improving their biocompatibility. It becomes therefore of crucial importance to determine whether chemically manipulated CNTs may maintain their performance in improving nerve signaling. Here we study and compare the impact in vitro on neuronal signaling of two classes of chemically modified multiwalled CNTs in reference to pristine CNTs, which are known to be a substrate able to boost neuronal growth and communication. We found that the extent of functionalization and the nature of the functional groups on MWNT sidewalls affect the conductivity and the biological effects of the final derivatives. This information is important for the future design of biointegrated devices

Infrared nanospectroscopy of individual extracellular microvesicles

Extracellular vesicles are membrane-delimited structures, involved in several inter-cellular communication processes, both physiological and pathological, since they deliver complex biological cargo. Extracellular vesicles have been identified as possible biomarkers of several pathological diseases; thus, their characterization is fundamental in order to gain a deep understanding of their function and of the related processes. Traditional approaches for the characterization of the molecular content of the vesicles require a large quantity of sample, thereby providing an average molecular profile, while their heterogeneity is typically probed by non-optical microscopies that, however, lack the chemical sensitivity to provide information of the molecular cargo. Here, we perform a study of individual microvesicles, a subclass of extracellular vesicles generated by the outward budding of the plasma membrane, released by two cultures of glial cells under different stimuli, by applying a state-of-the-art infrared nanospectroscopy technique based on the coupling of an atomic force microscope and a pulsed laser, which combines the label-free chemical sensitivity of infrared spectroscopy with the nanometric resolution of atomic force microscopy. By correlating topographic, mechanical and spectroscopic information of individual microvesicles, we identified two main populations in both families of vesicles released by the two cell cultures. Subtle differences in terms of nucleic acid content among the two families of vesicles have been found by performing a fitting procedure of the main nucleic acid vibrational peaks in the 1000–1250 cm-1 frequency range

Utility of Non-rule-based Visual Matching as a Strategy to Allow Novices to Achieve Skin Lesion Diagnosis

Non-analytical reasoning is thought to play a key role in dermatology diagnosis. Considering its potential importance, surprisingly little work has been done to research whether similar identification processes can be supported in non-experts. We describe here a prototype diagnostic support software, which we have used to examine the ability of medical students (at the beginning and end of a dermatology attachment) and lay volunteers, to diagnose 12 images of common skin lesions. Overall, the non-experts using the software had a diagnostic accuracy of 98% (923/936) compared with 33% for the control group (215/648) (Wilcoxon p < 0.0001). We have demonstrated, within the constraints of a simplified clinical model, that novices’ diagnostic scores are significantly increased by the use of a structured image database coupled with matching of index and referent images. The novices achieve this high degree of accuracy without any use of explicit definitions of likeness or rule-based strategies

ERG conductance expression modulates the excitability of ventral horn GABAergic interneurons that control rhythmic oscillations in the developing mouse spinal cord

During antenatal development, the operation and maturation of mammalian spinal networks strongly depend on the activity of ventral horn GABAergic interneurons that mediate excitation first and inhibition later. Although the functional consequence of GABA actions may depend on maturational processes in target neurons, it is also likely that evolving changes in GABAergic transmission require fine-tuning in GABA release, probably via certain intrinsic mechanisms regulating GABAergic neuron excitability at different embryonic stages. Nevertheless, it has not been possible, to date, to identify certain ionic conductances upregulated or downregulated before birth in such cells. By using an experimental model with either mouse organotypic spinal cultures or isolated spinal cord preparations, the present study examined the role of the ERG current (IK(ERG) ), a potassium conductance expressed by developing, GABA-immunoreactive spinal neurons. In organotypic cultures, only ventral interneurons with fast adaptation and GABA immunoreactivity, and only after 1 week in culture, were transformed into high-frequency bursters by E4031, a selective inhibitor of IK(ERG) that also prolonged and made more regular spontaneous bursts. In the isolated spinal cord in which GABA immunoreactivity and m-erg mRNA were colocalized in interneurons, ventral root rhythms evoked by NMDA plus 5-hydroxytryptamine were stabilized and synchronized by E4031. All of these effects were lost after 2 weeks in culture or before birth in coincidence with decreased m-erg expression. These data suggest that, during an early stage of spinal cord development, the excitability of GABAergic ventral interneurons important for circuit maturation depended, at least in part, on the function of IK(ERG)

Inhibition of Immune Synapse by Altered Dendritic Cell Actin Distribution: A New Pathway of Mesenchymal Stem Cell Immune Regulation

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Tuning the reduction of graphene oxide nanoflakes differently affects neuronal networks in the zebrafish

The increasing engineering of biomedical devices and the design of drug-delivery platforms enriched by graphene-based components demand careful investigations of the impact of graphene-related materials (GRMs) on the nervous system. In addition, the enhanced diffusion of GRM-based products and technologies that might favor the dispersion in the environment of GRMs nanoparticles urgently requires the potential neurotoxicity of these compounds to be addressed. One of the challenges in providing definite evidence supporting the harmful or safe use of GRMs is addressing the variety of this family of materials, with GRMs differing for size and chemistry. Such a diversity impairs reaching a unique and predictive picture of the effects of GRMs on the nervous system. Here, by exploiting the thermal reduction of graphene oxide nanoflakes (GO) to generate materials with different oxygen/carbon ratios, we used a high-throughput analysis of early-stage zebrafish locomotor behavior to investigate if modifications of a specific GRM chemical property influenced how these nanomaterials affect vertebrate sensory-motor neurophysiology—exposing zebrafish to GO downregulated their swimming performance. Conversely, reduced GO (rGO) treatments boosted locomotor activity. We concluded that the tuning of single GRM chemical properties is sufficient to produce differential effects on nervous system physiology, likely interfering with different signaling pathways

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

Graphene unique physicochemical properties made it prominent among other allotropic forms of carbon, in many areas of research and technological applications. Interestingly, in recent years, many studies exploited the use of graphene family nanomaterials (GNMs) for biomedical applications such as drug delivery, diagnostics, bioimaging, and tissue engineering research. GNMs are successfully used for the design of scaffolds for controlled induction of cell differentiation and tissue regeneration. Critically, it is important to identify the more appropriate nano/bio material interface sustaining cells differentiation and tissue regeneration enhancement. Specifically, this review is focussed on graphene-based scaffolds that endow physiochemical and biological properties suitable for a specific tissue, the nervous system, that links tightly morphological and electrical properties. Different strategies are reviewed to exploit GNMs for neuronal engineering and regeneration, material toxicity, and biocompatibility. Specifically, the potentiality for neuronal stem cells differentiation and subsequent neuronal network growth as well as the impact of electrical stimulation through GNM on cells is presented. The use of field effect transistor (FET) based on graphene&nbsp;for neuronal regeneration is described. This review concludes the important aspects to be controlled to make graphene a promising candidate for further advanced application in neuronal tissue engineering and biomedical use