Lateral dimension and amino-functionalization on the balance to assess the single-cell toxicity of graphene on fifteen immune cell types

Graphene oxide films as a novel tool for the modulation of myeloid-derived suppressor cell activity in the context of multiple sclerosis

Despite the pharmacological arsenal approved for Multiple Sclerosis (MS), there are treatment-reluctant patients for whom cell therapy appears as the only therapeutic alternative. Myeloid-derived suppressor cells (MDSCs) are immature cells of the innate immunity able to control the immune response and to promote oligodendroglial differentiation in the MS animal model experimental autoimmune encephalomyelitis (EAE). However, when isolated and cultured for cell therapy purposes, MDSCs lose their beneficial immunomodulatory properties. To prevent this important drawback, culture devices need to be designed so that MDSCs maintain a state of immaturity and immunosuppressive function similar to that exerted in the donor organism. With this aim, we select graphene oxide (GO) as a promising candidate as it has been described as a biocompatible nanomaterial with the capacity to biologically modulate different cell types, yet its immunoactive potential has been poorly explored to date. In this work, we have fabricated GO films with two distintive redox and roughness properties and explore their impact in MDSC culture right after isolation. Our results show that MDSCs isolated from immune organs of EAE mice maintain an immature phenotype and highly immunosuppressive activity on T lymphocytes after being cultured on highly-reduced GO films (rGO200) compared to those grown on conventional glass coverslips. This immunomodulation effect is depleted when MDSCs are exposed to slightly rougher and more oxidized GO substrates (rGO90), in which cells experience a significant reduction in cell size associated with the activation of apoptosis. Taken together, the exposure of MDSCs to GO substrates with different redox state and roughness is presented as a good strategy to control MDSC activity in vitro. The versatility of GO nanomaterials in regards to the impact of their physico-chemical properties in immunomodulation opens the door to their selective therapeutic potential for pathologies where MDSCs need to be enhanced (MS) or inhibited (cancer).

Environmental and Health Impacts of Graphene and Other Two-Dimensional Materials: A Graphene Flagship Perspective

Two-dimensional (2D) materials have attracted tremendous interest ever since the isolation of atomically thin sheets of graphene in 2004 due to the specific and versatile properties of these materials. However, the increasing production and use of 2D materials necessitate a thorough evaluation of the potential impact on human health and the environment. Furthermore, harmonized test protocols are needed with which to assess the safety of 2D materials. The Graphene Flagship project (2013-2023), funded by the European Commission, addressed the identification of the possible hazard of graphene-based materials as well as emerging 2D materials including transition metal dichalcogenides, hexagonal boron nitride, and others. Additionally, so-called green chemistry approaches were explored to achieve the goal of a safe and sustainable production and use of this fascinating family of nanomaterials. The present review provides a compact survey of the findings and the lessons learned in the Graphene Flagship.

V4 C3 MXene Immune Profiling and Modulation of T Cell-Dendritic Cell Function and Interaction

Although vanadium-based metallodrugs are recently explored for their effective anti-inflammatory activity, they frequently cause undesired side effects. Among 2D nanomaterials, transition metal carbides (MXenes) have received substantial attention for their promise as biomedical platforms. It is hypothesized that vanadium immune properties can be extended to MXene compounds. Therefore, vanadium carbide MXene (V4 C3 ) is synthetized, evaluating its biocompatibility and intrinsic immunomodulatory effects. By combining multiple experimental approaches in vitro and ex vivo on human primary immune cells, MXene effects on hemolysis, apoptosis, necrosis, activation, and cytokine production are investigated. Furthermore, V4 C3 ability is demonstrated to inhibit T cell-dendritic cell interactions, evaluating the modulation of CD40-CD40 ligand interaction, two key costimulatory molecules for immune activation. The material biocompatibility at the single-cell level on 17 human immune cell subpopulations by single-cell mass cytometry is confirmed. Finally, the molecular mechanism underlying V4 C3 immune modulation is explored, demonstrating a MXene-mediated downregulation of antigen presentation-associated genes in primary human immune cells. The findings set the basis for further V4 C3 investigation and application as a negative modulator of the immune response in inflammatory and autoimmune diseases.

Evaluation of the Toxic Activity of the Graphene Oxide in the Ex Vivo Model of Human PBMC Infection with Mycobacterium tuberculosis

Graphene Oxide has been proposed as a potential adjuvant to develop improved anti-TB treatment, thanks to its activity in entrapping mycobacteria in the extracellular compartment limiting their entry in macrophages. Indeed, when administered together with linezolid, Graphene Oxide significantly enhanced bacterial killing due to the increased production of Reactive Oxygen Species. In this work, we evaluated Graphene Oxide toxicity and its anti-mycobacterial activity on human peripheral blood mononuclear cells. Our data show that Graphene Oxide, different to what is observed in macrophages, does not support the clearance of Mycobacterium tuberculosis in human immune primary cells, probably due to the toxic effects of the nano-material on monocytes and CD4+ lymphocytes, which we measured by cytometry. These findings highlight the need to test GO and other carbon-based nanomaterials in relevant in vitro models to assess the cytotoxic activity while measuring antimicrobial potential.

Trends and prospects in graphene and its derivatives toxicity research: A bibliometric analysis

The purpose of this paper is to explore the current research status, hot topics, and future prospects in the field of graphene and its derivatives toxicity. In the article, the Web of Science Core Collection database was used as the data source, and the CiteSpace and VOSviewer were used to conduct a visual analysis of the last 10 years of research on graphene and its derivatives toxicity. A total of 8573 articles were included, and we analyzed the literature characteristics of the research results in the field of graphene and its derivatives toxicity, as well as the distribution of authors and co-cited authors; the distribution of countries and institutions; the situation of co-cited references; and the distribution of journals and categories. The most prolific countries, institutions, journals, and authors are China, the Chinese Academy of Sciences, RSC Advances, and Wang, Dayong, respectively. The co-cited author with the most citations was Akhavan, Omid. The five research hotspot keywords in the field of graphene and its derivatives toxicity were "nanomaterials," "exposure," "biocompatibility," "adsorption," and "detection." Frontier topics were "facile synthesis," "antibacterial activity," and "carbon dots." Our study provides perspectives for the study of graphene and its derivatives toxicity and yields valuable information and suggestions for the development of graphene and its derivatives toxicity research in the future.

Understanding the bidirectional interactions between two-dimensional materials, microorganisms, and the immune system

Two-dimensional (2D) materials such as the graphene-based materials, transition metal dichalcogenides, transition metal carbides and nitrides (MXenes), black phosphorus, hexagonal boron nitride, and others have attracted considerable attention due to their unique physicochemical properties. This is true not least in the field of medicine. Understanding the interactions between 2D materials and the immune system is therefore of paramount importance. Furthermore, emerging evidence suggests that 2D materials may interact with microorganisms - pathogens as well as commensal bacteria that dwell in and on our body. We discuss the interplay between 2D materials, the immune system, and the microbial world in order to bring a systems perspective to bear on the biological interactions of 2D materials. The use of 2D materials as vectors for drug delivery and as immune adjuvants in tumor vaccines, and 2D materials to counteract inflammation and promote tissue regeneration, are explored. The bio-corona formation on and biodegradation of 2D materials, and the reciprocal interactions between 2D materials and microorganisms, are also highlighted. Finally, we consider the future challenges pertaining to the biomedical applications of various classes of 2D materials.