Graphene oxide induces toll-like receptor 4 (TLR4)-dependent necrosis in macrophages

Defining the immunological compatibility of graphene oxide-loaded PLGA scaffolds for biomedical applications

Graphene oxide (GO), a carbon-based nanomaterial, presents significant potential across biomedical fields such as bioimaging, drug delivery, biosensors, and phototherapy. This study examines the effects of integrating GO into poly(lactic-co-glycolic acid) (PLGA) scaffolds on human immune cell function. Our results demonstrate that high concentrations of GO reduce the viability of peripheral blood mononuclear cells (PBMCs) following stimulation with anti-CD3 antibody. This reduction extends to T lymphocyte activation, evident from the diminished proliferative response to T cell receptor engagement and impaired differentiation into T helper subsets and regulatory T cells. Interestingly, although GO induces a minimal response in resting monocytes, but it significantly affects both the viability and the differentiation potential of monocytes induced to mature toward M1 pro-inflammatory and M2-like immunoregulatory macrophages. This study seeks to address a critical gap by investigating the in vitro immunomodulatory effects of PLGA scaffolds incorporating various concentrations of GO on primary immune cells, specifically PBMCs isolated from healthy donors. Our findings emphasize the need to optimize the GO to PLGA ratios and scaffold design to advance PLGA-GO-based biomedical applications. STATEMENT OF SIGNIFICANCE: Graphene oxide (GO) holds immense promise for biomedical applications due to its unique properties. However, concerns regarding its potential to trigger adverse immune responses remain. This study addresses this critical gap by investigating the in vitro immunomodulatory effects of PLGA scaffolds incorporating increasing GO concentrations on human peripheral blood mononuclear cells (PBMCs). By elucidating the impact on cell viability, T cell proliferation and differentiation, and the maturation/polarization of antigen-presenting cells, this work offers valuable insights for designing safe and immunologically compatible GO-based biomaterials for future clinical translation.

Emergence of graphene as a novel nanomaterial for cardiovascular applications

Cardiovascular diseases (CDs) are the foremost cause of death worldwide. Several promising therapeutic methods have been developed for this approach, including pharmacological, surgical intervention, cell therapy, or biomaterial implantation since heart tissue is incapable of regenerating and healing on its own. The best treatment for heart failure to date is heart transplantation and invasive surgical intervention, despite their invasiveness, donor limitations, and the possibility of being rejected by the patient's immune system. To address these challenges, research is being conducted on less invasive and efficient methods. Consequently, graphene-based materials (GBMs) have attracted a great deal of interest in the last decade because of their exceptional mechanical, electrical, chemical, antibacterial, and biocompatibility properties. An overview of GBMs' applications in the cardiovascular system has been presented in this article. Following a brief explanation of graphene and its derivatives' properties, the potential of GBMs to improve and restore cardiovascular system function by using them as cardiac tissue engineering, stents, vascular bypass grafts,and heart valve has been discussed.

Perilous paradigm of graphene oxide and its derivatives in biomedical applications: Insight to immunocompatibility

With advancements in nanotechnology and innovative materials, Graphene Oxide nanoparticles (GONP) have attracted lots of attention among the diverse types of nanomaterials owing to their distinctive physicochemical characteristics. However, the usage at scientific and industrial level has also raised concern to their toxicological interaction with biological system. Understanding these interactions is crucial for developing guidelines and recommendations for applications of GONP in various sectors, like biomedicine and environmental technologies. This review offers crucial insights and an in-depth analysis to the biological processes associated with GONP immunotoxicity with multiple cell lines including human whole blood cultures, dendritic cells, macrophages, and multiple cancer cell lines. The complicated interactions between graphene oxide nanoparticles and the immune system, are highlighted in this work, which reveals a range of immunotoxic consequences like inflammation, immunosuppression, immunostimulation, hypersensitivity, autoimmunity, and cellular malfunction. Moreover, the immunotoxic effects are also highlighted with respect to in vivo models like mice and zebrafish, insighting GO Nanoparticles' cytotoxicity. The study provides invaluable review for researchers, policymakers, and industrialist to understand and exploit the beneficial applications of GONP with a controlled measure to human health and the environment.

Surface-modified injectable poly(ethylene-glycol) diacrylate-based cryogels for localized gene delivery

Lentiviral transduction is widely used in research, has shown promise in clinical trials involving gene therapy and has been approved for CAR-T cell immunotherapy. However, most modifications are doneex vivoand rely on systemic administration of large numbers of transduced cells for clinical applications. A novel approach utilizingin situbiomaterial-based gene delivery can reduce off-target side effects while enhancing effectiveness of the manipulation process. In this study, poly(ethylene glycol) diacrylate (PEGDA)-based scaffolds were developed to enablein situlentivirus-mediated transduction. Compared to other widely popular biomaterials, PEGDA stands out due to its robustness and cost-effectiveness. These scaffolds, prepared via cryogelation, are capable of flowing through surgical needles in bothin vitroandin vivoconditions, and promptly regain their original shape. Modification with poly(L-lysine) (PLL) enables lentivirus immobilization while interconnected macroporous structure allows cell infiltration into these matrices, thereby facilitating cell-virus interaction over a large surface area for efficient transduction. Notably, these preformed injectable scaffolds demonstrate hemocompatibility, cell viability and minimally inflammatory response as shown by ourin vitroandin vivostudies involving histology and immunophenotyping of infiltrating cells. This study marks the first instance of using preformed injectable scaffolds for delivery of lentivectors, which offers a non-invasive and localized approach for delivery of factors enablingin situlentiviral transduction suitable for both tissue engineering and immunotherapeutic applications.

Determining toxicity of europium oxide nanoparticles in immune cell components and hematopoiesis in dominant organs in mice: Role of lysosomal fluid interaction

Extensive application of rare earth element oxide nanoparticles (REE NPs) has raised a concern over the possible toxic health effects after human exposure. Once entering the body, REE NPs are primarily processed by phagocytes in particular macrophages and undergo biotic phosphate complexation in lysosomal compartment. Such biotransformation affects the target organs and in vivo fate of REE NPs after escaping the lysosomes. However, the immunomodulatory effects of intraphagolysosomal dissolved REE NPs remains insufficient. Here, europium oxide (Eu2O3) NPs were pre-incubated with phagolysosomal simulant fluid (PSF) to mimic the biotransformation of europium oxide (p-Eu2O3) NPs under acid phagolysosome conditions. We investigated the alteration in immune cell components and the hematopoiesis disturbance on adult mice after intravenous administration of Eu2O3 NPs and p-Eu2O3 NPs. Our results indicated that the liver and spleen were the main target organs for Eu2O3 NPs and p-Eu2O3 NPs. Eu2O3 NPs had a much higher accumulative potential in organs than p-Eu2O3 NPs. Eu2O3 NPs induced more alterations in immune cells in the spleen, while p-Eu2O3 NPs caused stronger response in the liver. Regarding hematopoietic disruption, Eu2O3 NPs reduced platelets (PLTs) in peripheral blood, which might be related to the inhibited erythrocyte differentiation in the spleen. By contrast, p-Eu2O3 NPs did not cause significant disturbance in peripheral PLTs. Our study demonstrated that the preincubation with PSF led to a distinct response in the immune system compared to the pristine REE NPs, suggesting that the potentially toxic effects induced by the release of NPs after phagocytosis should not be neglected, especially when evaluating the safety of NPs application in vivo.

Immunomodulatory and immune-toxicological role of nanoparticles: Potential therapeutic applications

Nowadays, Nanoparticle-based immunotherapeutic research has invoked global interest due to their unique properties. The immune system is a shielding structure that defends living things from external threats. Before the use of any materials in drug design, it is essential to study the immunological response to avoid triggering undesirable immune responses in the body. This review tries to summarize the properties, various applications, and immunotherapeutic aspects of NP-induced immunomodulation relating to therapeutic development and toxicity in human health. The role of NPs in the immune system and their modulatory functions, resulting in immunosuppression or immunostimulation, exerts benefits or dangers depending on their compositions, sizes, surface chemistry, and so forth. After NPs enter into the body, they can interact with body fluid exposing, them to different body proteins to form protein corona particles and other bio-molecules (DNA, RNA, sugars, etc.), which may alter their bioactivity. Phagocytes are the first immune cells that can interact with foreign materials including nanoparticles. Immunostimulation and immunosuppression operate in two distinct manners. Overall, functionalized nanocarriers optimized various therapeutic implications by stimulating the host immune system and regulating the tranquility of the host immune system. Among others, toxicity and bio-clearance of nanomaterials are always prime concerns at the preclinical and clinical stages before final approval. The interaction of nanoparticles with immune cells causes direct cell damage via apoptosis and necroses as well as immune signaling pathways also become influenced.

Chasing Graphene-Based Anticancer Drugs: Where are We Now on the Biomedical Graphene Roadmap?

Graphene and graphene-based materials have attracted growing interest for potential applications in medicine because of their good biocompatibility, cargo capability and possible surface functionalizations. In parallel, prototypic graphene-based devices have been developed to diagnose, imaging and track tumor growth in cancer patients. There is a growing number of reports on the use of graphene and its functionalized derivatives in the design of innovative drugs delivery systems, photothermal and photodynamic cancer therapy, and as a platform to combine multiple therapies. The aim of this review is to introduce the latest scientific achievements in the field of innovative composite graphene materials as potentially applied in cancer therapy. The "Technology and Innovation Roadmap" published in the Graphene Flagship indicates, that the first anti-cancer drugs using graphene and graphene-derived materials will have appeared on the market by 2030. However, it is necessary to broaden understanding of graphene-based material interactions with cellular metabolism and signaling at the functional level, as well as toxicity. The main aspects of further research should elucidate how treatment methods (e.g., photothermal therapy, photodynamic therapy, combination therapy) and the physicochemical properties of graphene materials influence their ability to modulate autophagy and kill cancer cells. Interestingly, recent scientific reports also prove that graphene nanocomposites modulate cancer cell death by inducing precise autophagy dysfunctions caused by lysosome damage. It turns out as well that developing photothermal oncological treatments, it should be taken into account that near-infrared-II radiation (1000-1500 nm) is a better option than NIR-I (750-1000 nm) because it can penetrate deeper into tissues due to less scattering at longer wavelengths radiation.

Graphene-based materials as nanoplatforms for antiviral therapy and prophylaxis

INTRODUCTION

The dramatic effects caused by viral diseases have prompted the search for effective therapeutic and preventive agents. In this context, 2D graphene-based nanomaterials (GBNs) have shown great potential for antiviral therapy, enabling the functionalization and/or decoration with biomolecules, metals and polymers, able to improve their interaction with viral nanoparticles.

AREAS COVERED

This review summarizes the most recent advances of the antiviral research related to 2D GBNs, based on their antiviral mechanism of action. Their ability to inactivate viruses by inhibiting the entry inside cells, or through drug/gene delivery, or by stimulating the host immune response are here discussed. As reported, biological studies performed in vitro and/or in vivo allowed to demonstrate the antiviral activity of the developed GBNs, at different stages of the virus life cycle and the evaluation of their long-term toxicity. Other mechanisms closely related to the physicochemical properties of GBNs are also reported, demonstrating the potential of these materials for antiviral prophylaxis.

EXPERT OPINION

GBNs represent valuable tools to fight emerging or reemerging viral infections. However, their translation into the clinic requires standardized scale-up procedures leading to the reliable and reproducible synthesis of these nanomaterials with suitable physicochemical properties, as well as more in-depth pharmacological and toxicological investigations. We believe that multidisciplinary approaches will give valuable solutions to overcome the encountered limitations in the application of GBNs in biomedical and clinical field.

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).

Nanoparticles with intermediate hydrophobicity polarize macrophages to plaque-specific Mox phenotype via Nrf2 and HO-1 activation

Mox macrophages were identified recently and are closely associated with atherosclerosis. Considering the potential health risks and the impact on macrophage modulation, this study investigated the Mox polarization of macrophages induced by nanoparticles (NPs) with tunable hydrophobicity. One nanoparticle (C4NP) with intermediate hydrophobicity efficiently upregulated the mRNA expression of Mox-related genes including HO-1, Srxn1, Txnrd1, Gsr, Vegf and Cox-2 through increased accumulation of Nrf2 at a nontoxic concentration in both resting and LPS-challenged macrophages. Additionally, C4NP impaired phagocytic capacity by 20% and significantly increased the secretion of cytokines, including TNFα, IL-6 and IL-10. Mechanistic studies indicated that intracellular reactive oxygen species (ROS) were elevated by 1.5-fold and 2.6-fold in resting and LPS-challenged macrophages respectively. Phosphorylated p62 was increased by 2.5-fold in resting macrophages and maintained a high level in LPS-challenged ones, both of which partially accounted for the significant accumulation of Nrf2 and HO-1. Notably, C4NP depolarized mitochondrial membrane potential by more than 50% and switched macrophages from oxidative phosphorylation-based aerobic metabolism to glycolysis for energy supply. Overall, this study reveals a novel molecular mechanism potentially involving ROS-Nrf2-p62 signaling in mediating macrophage Mox polarization, holding promise in ensuring safer and more efficient use of nanomaterials.

Graphene-Based Nanomaterials and Their Interactions with Lipid Membranes

Graphene-based nanomaterials (GNMs) have captured increasing attention in the recent advancement of materials science and nanotechnology owing to their excellent physicochemical properties. Despite having unquestionable advances, the application of GNMs in biological and medical sciences is still limited due to the lack of knowledge and precise control over their interaction with the biological milieu. The cellular membrane is the first barrier with which GNMs interact before entering a cell. Therefore, understanding how they interact with cell membranes is important from the perspective of safe use in biological and biomedical fields. In this review, we systematically summarize the recent efforts in predicting the interactions between GNMs and model cellular membranes. This review provides insights into how GNMs interact with lipid membranes and self-assemble in and around them. Both the computational simulations and experimental observations are summarized. The interactions are classified depending on the physicochemical properties (structure, chemistry, and orientation) of GNMs and various model membranes. The thermodynamic parameters, structural details, and supramolecular forces are listed to understand the interactions which would help circumvent potential risks and provide guidance for safe use in the future. At the end of this review, future prospective and emerging challenges in this research field are discussed.

Graphene oxide as novel vaccine adjuvant

To improve antigen immunogenicity and promote long-lasting immunity, vaccine formulations have been appropriately supplemented with adjuvants. Graphene has been found to enhance the presentation of antigens to CD8+ T cells, as well as stimulating innate immune responses and inflammatory factors. Its properties, such as large surface area, water stability, and high aspect ratio, make it a suitable candidate for delivering biological substances. Graphene-based nanomaterials have recently attracted significant attention as a new type of vaccine adjuvants due to their potential role in the activation of immune responses. Due to the limited functionality of some approved human adjuvants for use, the development of new all-purpose adjuvants is urgently required. Research on the immunological and biomedical use of graphene oxide (GO) indicates that these nanocarriers possess excellent physicochemical properties, acceptable biocompatibility, and a high capacity for drug loading. Graphene-based nanocarriers also could improve the function of some immune cells such as dendritic cells and macrophages through specific signaling pathways. However, GO injection can lead to significant oxidative stress and inflammation. Various surface functionalization protocols have been employed to reduce possible adverse effects of GO, such as aggregation of GO in biological liquids and induce cell death. Furthermore, these modifications enhance the properties of functionalized-GO's qualities, making it an excellent carrier and adjuvant. Shedding light on different physicochemical and structural properties of GO and its derivatives has led to their application in various therapeutic and drug delivery fields. In this review, we have endeavored to elaborate on different aspects of GO.

Graphene-Based Material-Mediated Immunomodulation in Tissue Engineering and Regeneration: Mechanism and Significance

Tissue engineering and regenerative medicine hold promise for improving or even restoring the function of damaged organs. Graphene-based materials (GBMs) have become a key player in biomaterials applied to tissue engineering and regenerative medicine. A series of cellular and molecular events, which affect the outcome of tissue regeneration, occur after GBMs are implanted into the body. The immunomodulatory function of GBMs is considered to be a key factor influencing tissue regeneration. This review introduces the applications of GBMs in bone, neural, skin, and cardiovascular tissue engineering, emphasizing that the immunomodulatory functions of GBMs significantly improve tissue regeneration. This review focuses on summarizing and discussing the mechanisms by which GBMs mediate the sequential regulation of the innate immune cell inflammatory response. During the process of tissue healing, multiple immune responses, such as the inflammatory response, foreign body reaction, tissue fibrosis, and biodegradation of GBMs, are interrelated and influential. We discuss the regulation of these immune responses by GBMs, as well as the immune cells and related immunomodulatory mechanisms involved. Finally, we summarize the limitations in the immunomodulatory strategies of GBMs and ideas for optimizing GBM applications in tissue engineering. This review demonstrates the significance and related mechanism of the immunomodulatory function of GBM application in tissue engineering; more importantly, it contributes insights into the design of GBMs to enhance wound healing and tissue regeneration in tissue engineering.

In vitro safety assessment of reduced graphene oxide in human monocytes and T cells

Considering the increase in the use of graphene derivatives in different fields, the environmental and human exposure to these materials is likely, and the potential consequences are not fully elucidated. This study is focused on the human immune system, as this plays a key role in the organism's homeostasis. In this sense, the cytotoxicity response of reduced graphene oxide (rGO) was investigated in monocytes (THP-1) and human T cells (Jurkat). A mean effective concentration (EC₅₀-24 h) of 121.45 ± 11.39 μg/mL and 207.51 ± 21.67 μg/mL for cytotoxicity was obtained in THP-1 and Jurkat cells, respectively. rGO decreased THP-1 monocytes differentiation at the highest concentration after 48 h of exposure. Regarding the inflammatory response at genetic level, rGO upregulated IL-6 in THP-1 and all cytokines tested in Jurkat cells after 4 h of exposure. At 24 h, IL-6 upregulation was maintained, and a significant decrease of TNF-α gene expression was observed in THP-1 cells. Moreover, TNF-α, and INF-γ upregulation were maintained in Jurkat cells. With respect to the apoptosis/necrosis, gene expression was not altered in THP-1 cells, but a down regulation of BAX and BCL-2 was observed in Jurkat cells after 4 h of exposure. These genes showed values closer to negative control after 24 h. Finally, rGO did not trigger a significant release of any cytokine at any exposure time assayed. In conclusion, our data contributes to the risk assessment of this material and suggest that rGO has an impact on the immune system whose final consequences should be further investigated.

Implications of ferroptosis in silver nanoparticle-induced cytotoxicity of macrophages

Metal nanoparticles (NPs) are widely used in daily life and commercial activities owing to their unique physicochemical properties. Consequently, there is an increasing risk of daily and occupational exposure to metal NPs, which raises concerns regarding their health hazards. Programmed cell deaths (PCDs) have been clarified to be involved in metal NP-induced cytotoxicity, including apoptosis, autophagy, and pyroptosis. However, whether and how ferroptosis, a newly recognized PCD, contributes to metal NP-induced cell death remain unclear. In this study, we investigated the ferroptotic effects of two representative metal NPs, silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs), on macrophages in vitro. Our results revealed that AgNPs, rather than AuNPs, induced non-apoptotic PCD, accompanied by lipid peroxidation and iron homeostasis disorders, which are two hallmarks of ferroptosis, in macrophages. Treatment with a ferroptosis inhibitor (ferrostatin-1) and iron chelator (deferoxamine) reversed AgNP-induced PCD, corroborating the induction of ferroptosis upon exposure to AgNPs. Moreover, our results revealed that smaller AgNPs elicited greater ferroptotic effects on macrophages than larger ones. Importantly, ferroptosis in AgNP-treated macrophages was mainly triggered by AgNPs per se rather than by Ag ions. Overall, our study highlights the ferroptotic effects elicited by AgNPs in macrophages, which will promote the understanding of their cytotoxic effects and facilitate the safer design of metal nanoproducts.

Computer-Aided Discovery of Potent Broad-Spectrum Vaccine Adjuvants

Adjuvants stimulate the immune system to vigorously respond to a vaccine. While current adjuvants such as aluminum salts and oil-in-water emulsions have been used for decades, they do not generate broad and long-lasting responses in many vaccines. Consequently, more potent adjuvants are needed. Here, using computer-aided molecule design and machine learning, we discovered 2 new, broad-spectrum adjuvants that can boost vaccine responses. Our library containing 46 toll-like receptor (TLR)-targeting agonist ligands were assembled on Au nanoparticles. Comprehensive in vitro, ex vivo and in vivo studies showed both leads promoted dendritic cell activation via multiple TLRs and enhanced antigen presentation to T cells. When used together with tumor-specific antigens to immunize mice against B16-OVA melanoma and 4T1-PD1 breast cancer, both adjuvants unleashed strong immune responses that suppressed tumor growth and lung metastases. Our results show computer-aided design and screening can rapidly uncover potent adjuvants for tackling waning immunity in current vaccines.

Progress and challenges of graphene and its congeners for biomedical applications

Nanomaterials by virtue of their small size and enhanced surface area, present unique physicochemical properties that enjoy widespread applications in bioengineering, biomedicine, biotechnology, disease diagnosis, and therapy. In recent years, graphene and its derivatives have attracted a great deal of attention in various applications, including photovoltaics, electronics, energy storage, catalysis, sensing, and biotechnology owing to their exceptional structural, optical, thermal, mechanical, and electrical. Graphene is a two-dimensional sheet of sp2 hybridized carbon atoms of atomic thickness, which are arranged in a honeycomb crystal lattice structure. Graphene derivatives are graphene oxide (GO) and reduced graphene oxide (rGO), which are highly oxidized and less oxidized forms of graphene, respectively. Another form of graphene is graphene quantum dots (GQDs), having a size of less than 20 nm. Contemporary graphene research focuses on using graphene nanomaterials for biomedical purposes as they have a large surface area for loading biomolecules and medicine and offer the potential for the conjugation of fluorescent dyes or quantum dots for bioimaging. The present review begins with the synthesis, purification, structure, and properties of graphene nanomaterials. Then, we focussed on the biomedical application of graphene nanomaterials with special emphasis on drug delivery, bioimaging, biosensing, tissue engineering, gene delivery, and chemotherapy. The implications of graphene nanomaterials on human health and the environment have also been summarized due to their exposure to their biomedical applications. This review is anticipated to offer useful existing understanding and inspire new concepts to advance secure and effective graphene nanomaterials-based biomedical devices.

Formulated Phospholipids as Non-Canonical TLR4 Agonists

Immunogenic agents known as adjuvants play a critical role in many vaccine formulations. Adjuvants often signal through Toll-like receptor (TLR) pathways, including formulations in licensed vaccines that target TLR4. While TLR4 is predominantly known for responding to lipopolysaccharide (LPS), a component of Gram-negative bacterial membranes, it has been shown to be a receptor for a number of molecular structures, including phospholipids. Therefore, phospholipid-based pharmaceutical formulations might have off-target effects by signaling through TLR4, confounding interpretation of pharmaceutical bioactivity. In this study we examined the individual components of a clinical stage oil-in-water vaccine adjuvant emulsion (referred to as a stable emulsion or SE) and their ability to signal through murine and human TLR4s. We found that the phospholipid 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) activated TLR4 and elicited many of the same immune phenotypes as canonical TLR4 agonists. This pathway was dependent on the saturation, size, and headgroup of the phospholipid. Interestingly, DMPC effects on human cells were evident but overall appeared less impactful than emulsion oil composition. Considering the prevalence of DMPC and other phospholipids used across the pharmaceutical space, these findings may contextualize off-target innate immune responses that could impact preclinical and clinical development.

Intracellular fate and immune response of porphyrin-based nano-sized metal-organic frameworks

The diverse applications of porphyrin-based nano-sized metal-organic frameworks (NMOFs) lead to great exposure risks to human and environment. Understanding the cellular biological effects (such as toxicity, distribution, and localization) of porphyrinic NMOFs is a prerequisite to the assessment of their health risk. However, the characteristics of distribution, localization, and immune response induced by porphyrinic NMOFs have not been studied yet. Here, we report the size-dependent biological effects of porphyrinic NMOFs under sublethal dose. Various sizes of PCN-224 (30, 90, and 180 nm) were taken as model porphyrinic NMOFs. We found that 30 nm PCN-224 gave the highest uptake content, followed by 90 and 180 nm PCN-224. The mechanism for uptake was clathrin-mediated for 30 and 90 nm PCN-224, but clathrin- and glycosylphosphatidylinositol-mediated for 180 nm PCN-224. All PCN-224 were localized in lysosome with size-dependent velocity of colocalization transport. 30 nm PCN-224 induced the highest released cytokines than 90 and 180 nm PCN-224 accompanied with the activation of NF-κB pathway. This work reveals the mechanisms for the endocytosis of PCN-224 and the release of cytokine induced by PCN-224, which is helpful for the health risk assessment of NMOFs.

Self-assembled flagella protein nanofibers induce enhanced mucosal immunity

Nanofibers are potential vaccines or adjuvants for vaccination at the mucosal interface. However, how their lengths affect the mucosal immunity is not well understood. Using length-tunable flagella (self-assembled from a protein termed flagellin) as model protein nanofibers, we studied the mechanisms of their interaction with mucosal interface to induce immune responses length-dependently. Briefly, through tuning flagellin assembly, length-controlled protein nanofibers were prepared. The shorter nanofibers exhibited more pronounced toll-like receptor 5 (TLR5) and inflammasomes activation accompanied by pyroptosis, as a result of cellular uptake, lysosomal damage, and mitochondrial reactive oxygen species generation. Accordingly, the shorter nanofibers elevated the IgA level in mucosal secretions and enhanced the serum IgG level in ovalbumin-based intranasal vaccinations. These mucosal and systematic antibody responses were correlated with the mucus penetration capacity of the nanofibers. Intranasal administration of vaccines (human papillomavirus type 16 peptides) adjuvanted with shorter nanofibers significantly elicited cytotoxic T lymphocyte responses, strongly inhibiting tumor growth and improving survival rates in a TC-1 cervical cancer model. This work suggests that length-dependent immune responses of nanofibers can be elucidated for designing nanofibrous vaccines and adjuvants for both infectious diseases and cancer.

Size- and shape-dependent cytotoxicity of nano-sized Zr-based porphyrinic metal-organic frameworks to macrophages

The wide utilization of nano-sized metal-organic frameworks (NMOFs) leads to inevitable health risks to humans. Previous studies on health risks of NMOFs mainly focus on the cytotoxic tests of typical NMOFs，but lack sufficient studies on the effects of physiochemical characteristics of NMOFs on the cytotoxicity and the related mechanisms. Here, four kinds of Zr-based porphyrinic NMOFs (PCNs), including spherical 30, 90, and 180 nm PCN-224 and rod-like 90 nm PCN-222, were taken as a proof of the concept to investigate the effects of the size and shape of NMOFs on the cytotoxicity and related mechanisms to macrophages. The 30 nm spherical PCN-224 induced significant rupture of cell membrane and dissolved in lysosome, leading to the most significant cell necrosis among the studied other nano-sized PCNs. However, other studied PCNs showed insignificant membrane rupture and their dissolution in lysosome. Furthermore, the 90 nm-sized PCN-224 led to much more significant cell necrosis by inducing lysosome damage and inhibiting of autophagy flux than the rod-like 90 nm PCN-222. These findings reveal the size- and shape-dependent cytotoxicity of PCNs and the related mechanisms and are helpful to the assessment of the potential health risks of NMOFs and the safe application of NMOFs.

Immunotoxicity of Carbon-Based Nanomaterials, Starring Phagocytes

In the field of science, technology and medicine, carbon-based nanomaterials and nanoparticles (CNMs) are becoming attractive nanomaterials that are increasingly used. However, it is important to acknowledge the risk of nanotoxicity that comes with the widespread use of CNMs. CNMs can enter the body via inhalation, ingestion, intravenously or by any other route, spread through the bloodstream and penetrate tissues where (in both compartments) they interact with components of the immune system. Like invading pathogens, CNMs can be recognized by large numbers of receptors that are present on the surface of innate immune cells, notably monocytes and macrophages. Depending on the physicochemical properties of CNMs, i.e., shape, size, or adsorbed contamination, phagocytes try to engulf and process CNMs, which might induce pro/anti-inflammatory response or lead to modulation and disruption of basic immune activity. This review focuses on existing data on the immunotoxic potential of CNMs, particularly in professional phagocytes, as they play a central role in processing and eliminating foreign particles. The results of immunotoxic studies are also described in the context of the entry routes, impacts of contamination and means of possible elimination. Mechanisms of proinflammatory effect depending on endocytosis and intracellular distribution of CNMs are highlighted as well.

Intratracheal instillation of graphene oxide decreases anti-virus responses and lipid contents via suppressing Toll-like receptor 3 in mouse livers

Recent studies revealed a causal relationship between Toll-like receptors (TLRs) and lipid droplet biogenesis. Interestingly, it has been reported before that nanomaterials (NMs) were capable to modulate TLRs, but it remains unclear if NMs could affect lipid levels via TLR signaling pathways. In this study, we investigated the influences of airway exposure to graphene oxide (GO) on TLR3 signaling pathways and lipid levels in mouse livers. Intratracheal instillation of GO (0.1, 1, and 5 mg/kg, once a day, totally 5 days) induced inflammatory cell infiltrations as indicated by hematoxylin-eosin (H&E) staining and fibrosis as indicated by Masson staining in lungs, accompanying with decreased TLR3 proteins. Consistently, a TLR3-regulated anti-virus protein, namely interferon induced protein with tetratricopeptide repeats 1 (IFIT1), as well as two TLR3-regulated lipid proteins, namely radical S-adenosyl methionine domain containing 2 (RSAD2) and perilipin 2 (PLIN2), were decreased in lungs. The protein levels of interferon-β in serum were also decreased. In livers, GO exposure induced disorganization of liver cells but not fibrosis. In agreement with the trends observed in lungs, TLR3, IFIT1, RSAD2, and PLIN2 proteins were decreased in livers. As a possible consequence, GO exposure dose-dependently decreased lipid levels in livers as indicated by oil red O and BODIPY 493/503 staining. We concluded that airway exposure to GO decreased anti-virus responses and lipid levels in mouse livers via the suppression of TLR3.

Subchronic Graphene Exposure Reshapes Skin Cell Metabolism

In recent years, the toxicity of graphene-related materials (GRMs) has been evaluated in diverse models to guarantee their safety. In most applications, sublethal doses of GRMs contact human barriers such as skin in a subchronic way. Herein, the subchronic effect (30 day exposure) of three GRMs (GO 1, GO 2, and FLG) with different oxidation degrees and sizes was studied. The effects of these materials on human skin cells, HaCaTs, were assayed through high-throughput metabolic-based readout and other cell-based assays. A differential effect was found between the different GRMs. GO 2 induced a metabolic remodeling in epithelial cells, increasing the level of tricarboxylic acid components, mirrored by increased cell proliferation and changes in cell phenotype. The oxidation degree, size, and method of manufacture of GRMs dictated harmful effects on cell metabolism and behavior generated by nontoxic exposures. Therefore, a “safe by design” procedure is necessary when working with these nanomaterials.

Ageing Significantly Alters the Physicochemical Properties and Associated Cytotoxicity Profiles of Ultrafine Particulate Matters towards Macrophages

There are still significant concerns about the detrimental effects and health risks of particulate matters (PMs) on the respiratory system. Notably, a largely overlooked knowledge gap is whether the environmental ageing process would change the physicochemical properties of PMs as well as the toxic influences of PMs on macrophages. Here, we applied ambient treatment of model PMs to mimic the real O3-induced ageing process and investigated ageing-determined cytotoxicity profile changes of PMs towards macrophages. The consequent distinct bioreactivity and toxicity towards macrophages are largely attributed to the changes of species of surface O-functional groups. Importantly, we unveiled the specific interactions between aged PMs and macrophages due to the variant contents of the surface carboxyl group, resulting in the divergent inflammatory activations and immune balance in the lung. Collectively, this study unearths the significance of ageing in altering particle cytotoxicity, and also provides additional understandings for consecutive investigations on the adverse effects of air pollution on the respiratory system.

Regulatory T Cells: Angels or Demons in the Pathophysiology of Sepsis?

Sepsis is a syndrome characterized by life-threatening organ dysfunction caused by the dysregulated host response to an infection. Sepsis, especially septic shock and multiple organ dysfunction is a medical emergency associated with high morbidity, high mortality, and prolonged after-effects. Over the past 20 years, regulatory T cells (Tregs) have been a key topic of focus in all stages of sepsis research. Tregs play a controversial role in sepsis based on their heterogeneous characteristics, complex organ/tissue-specific patterns in the host, the multi-dimensional heterogeneous syndrome of sepsis, the different types of pathogenic microbiology, and even different types of laboratory research models and clinical research methods. In the context of sepsis, Tregs may be considered both angels and demons. We propose that the symptoms and signs of sepsis can be attenuated by regulating Tregs. This review summarizes the controversial roles and Treg checkpoints in sepsis.

Graphene Particles Interfere with Pro-Inflammatory Polarization of Human Macrophages: Functional and Electrophysiological Evidence

The interaction of two types of fragmented graphene particles (30-160 nm) with human macrophages is studied. Since macrophages have significant phagocytic activity, the incorporation of graphene particles into cells has an effect on the response to functional polarization stimuli, favoring an anti-inflammatory profile. Incubation of macrophages with graphene foam particles, prepared by chemical vapor deposition, and commercially available graphene nanoplatelet particles does not affect cell viability when added at concentrations up to 100 µg mL^-1 ; macrophages exhibit differential quantitative responses to each type of graphene particles. Although both materials elicit similar increases in the release of reactive oxygen species, the impact on the transcriptional regulation associated with the polarization profile is different; graphene nanoplatelets significantly modify this transcriptomic profile. Moreover, these graphene particles differentially affect the motility and phagocytosis of macrophages. After the incorporation of both graphene types into the macrophages, they exhibit specific responses in terms of the mitochondrial oxygen consumption and electrophysiological potassium currents at the cell plasma membrane. These data support the view that the physical structure of the graphene particles has an impact on human macrophage responses, paving the way for the development of new mechanisms to modulate the activity of the immune system.

Safety Evaluation of Nanotechnology Products

Nanomaterials are now being used in a wide variety of biomedical applications. Medical and health-related issues, however, have raised major concerns, in view of the potential risks of these materials against tissue, cells, and/or organs and these are still poorly understood. These particles are able to interact with the body in countless ways, and they can cause unexpected and hazardous toxicities, especially at cellular levels. Therefore, undertaking in vitro and in vivo experiments is vital to establish their toxicity with natural tissues. In this review, we discuss the underlying mechanisms of nanotoxicity and provide an overview on in vitro characterizations and cytotoxicity assays, as well as in vivo studies that emphasize blood circulation and the in vivo fate of nanomaterials. Our focus is on understanding the role that the physicochemical properties of nanomaterials play in determining their toxicity.

Mechanistic actions and contributing factors affecting the antibacterial property and cytotoxicity of graphene oxide

Recent advances in the field of nanotechnology contributed to the increasing use of nanomaterials in the engineering, health and biological sectors. Graphene oxide (GO) has great potentials as it could be fine-tuned to be adapted into various applications, especially in the electrical, electronic, industrial and clinical fields. One of the important applications of GO is its use as an antibacterial material due to its promising activity against a broad range of bacteria. However, our understanding of the mechanism of action of GO towards bacteria is still lacking and is often less described. Therefore, a comprehensive overview of bactericidal mechanistic actions of GO and the roles of physicochemical factors including size, aggregation, functionalization and adsorption behavior contributing to its antibacterial activities are described in this review. As the use of GO is expected to increase exponentially in the health sector, the cytotoxicity of GO among the cell lines is also discussed. Thus, this review emphasizes the physicochemical characteristics of GO that can be tailored for optimal antibacterial properties that is of importance to the health industry.

Surface charge-dependent mitochondrial response to similar intracellular nanoparticle contents at sublethal dosages

Background

Considering the inevitability for humans to be frequently exposed to nanoparticles (NPs), understanding the biosafety of NPs is important for rational usage. As an important part of the innate immune system, macrophages are widely distributed in vital tissues and are also a dominant cell type that engulfs particles. Mitochondria are one of the most sensitive organelles when macrophages are exposed to NPs. However, previous studies have mainly reported the mitochondrial response upon high-dose NP treatment. Herein, with gold nanoparticles (AuNPs) as a model, we investigated the mitochondrial alterations induced by NPs at a sublethal concentration.

Results

At a similar internal exposure dose, different AuNPs showed distinct degrees of effects on mitochondrial alterations, including reduced tubular mitochondria, damaged mitochondria, increased reactive oxygen species, and decreased adenosine triphosphate. Cluster analysis, two-way ANOVA, and multiple linear regression suggested that the surface properties of AuNPs were the dominant determinants of the mitochondrial response. Based on the correlation analysis, the mitochondrial response was increased with the change in zeta potential from negative to positive. The alterations in mitochondrial respiratory chain proteins indicated that complex V was an indicator of the mitochondrial response to low-dose NPs.

Conclusion

Our current study suggests potential hazards of modified AuNPs on mitochondria even under sublethal dose, indicates the possibility of surface modification in biocompatibility improvement, and provides a new way to better evaluation of nanomaterials biosafety.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12989-021-00429-8.

In Vitro Assessment of the Genotoxic Potential of Pristine Graphene Platelets

(1) Background: Graphene is a two-dimensional atomic structure with a wide range of uses, including for biomedical applications. However, knowledge of its hazards is still limited. This work brings new cytotoxic, cytostatic, genotoxic and immunotoxic data concerning the in vitro exposure of human cell line to two types of graphene platelets (GP). It also contributes to the formation of general conclusions about the health risks of GP exposure. (2) Methods: In vitro exposure of a THP-1 cell line to three concentrations of two GP over 40 h. The cytotoxic potential was assessed by the measurement of LDH and glutathione (ROS) and by a trypan blue exclusion assay (TBEA); the cytostatic and genotoxic potential were assessed by the cytokinesis-block micronucleus (CBMN) test; and the immunotoxic potential was assessed by the measurement of IL-6, IL-10 and TNF-α. (3) Results: We found a significant dose-dependent increase in DNA damage (CBMN). The lowest observed genotoxic effect levels (LOGEL) were 5 µg/mL (GP1) and 30 µg/mL (GP2). We found no significant leaking of LDH from cells, increase in dead cells (TBEA), induction of ROS, increased levels of cytostasis, or changes in IL-6, IL-10 and TNF-α levels. (4) Conclusions: The genotoxicity increased during the short-term in vitro exposure of THP-1 to two GP. No increase in cytotoxicity, immunotoxicity, or cytostasis was observed.

Stimulation of Innate and Adaptive Immune Cells with Graphene Oxide and Reduced Graphene Oxide Affect Cancer Progression

Sole nanomaterials or nanomaterials bound to specific biomolecules have been proposed to regulate the immune system. These materials have now emerged as new tools for eliciting immune-based therapies to treat various cancers. Graphene, graphene oxide (GO) and reduced GO (rGO) are the latest nanomaterials among other carbon nanotubes that have attracted wide interest among medical industry players due to their extraordinary properties, inert-state, non-toxic and stable dispersion in a various solvent. Currently, GO and rGO are utilized in various biomedical application including cancer immunotherapy. This review will highlight studies that have been carried out in elucidating the stimulation of GO and rGO on selected innate and adaptive immune cells and their effect on cancer progression to shed some insights for researchers in the development of various GO- and rGO-based immune therapies against various cancers.

Recent progress of graphene oxide-based multifunctional nanomaterials for cancer treatment

Background

In the last decade, graphene oxide-based nanomaterials, such as graphene oxide (GO) and reduced graphene oxide (rGO), have attracted more and more attention in the field of biomedicine. Due to the versatile surface functionalization, ultra-high surface area, and excellent biocompatibility of graphene oxide-based nanomaterials, which hold better promise for potential applications than among other nanomaterials in biomedical fields including drug/gene delivery, biomolecules detection, tissue engineering, especially in cancer treatment.

Results

Here, we review the recent progress of graphene oxide-based multifunctional nanomaterials for cancer treatment. A comprehensive and in-depth depiction of unique property of graphene oxide-based multifunctional nanomaterials is first interpreted, with particular descriptions about the suitability for applying in cancer therapy. Afterward, recently emerging representative applications of graphene oxide-based multifunctional nanomaterials in antitumor therapy, including as an ideal carrier for drugs/genes, phototherapy, and bioimaging, are systematically summarized. Then, the biosafety of the graphene oxide-based multifunctional nanomaterials is reviewed.

Conclusions

Finally, the conclusions and perspectives on further advancing the graphene oxide-based multifunctional nanomaterials toward potential and versatile development for fundamental researches and nanomedicine are proposed.

Graphic abstract

Binding of Benzo[a]pyrene Alters the Bioreactivity of Fine Biochar Particles toward Macrophages Leading to Deregulated Macrophagic Defense and Autophagy

Contaminant-bearing fine biochar particles (FBPs) may exert significantly different toxicity profiles from their contaminant-free counterparts. While the role of FBPs in promoting contaminant uptake has been recognized, it is unclear whether the binding of contaminants can modify the biochemical reactivity and toxicological profiles of FBPs. Here, we show that binding of benzo[a]pyrene (B(a)P, a model polycyclic aromatic hydrocarbon) at environmentally relevant exposure concentrations markedly alters the cytotoxicity of FBPs to macrophages, an important line of innate immune defense against airborne particulate matters (PMs). Specifically, B(a)P-bearing FBPs elicit more severe disruption of the phospholipid membrane, endocytosis, oxidative stress, autophagy, and compromised innate immune defense, as evidenced by blunted proinflammatory effects, compared with B(a)P-free FBPs. Notably, the altered cytotoxicity cannot be attributed to the dissolution of B(a)P from the B(a)P-bearing FBPs, but appears to be related to B(a)P adsorption-induced changes of FBPs bioreactivity toward macrophages. Our findings highlight the significance of environmental chemical transformation in altering the bioreactivity and toxicity of PMs and call for further studies on other types of carbonaceous nanoparticles and additional exposure scenarios.

Graphene Family Nanomaterials in Ocular Applications: Physicochemical Properties and Toxicity

Graphene family nanomaterials (GFNs) are rapidly emerging for ocular applications due to their outstanding physicochemical properties. Since the eyes are very sensitive organs and the contact between the eyes and GFNs in eye drops, contact lenses, intraocular drug delivery systems and biosensors and even the workers handling these nanomaterials is inevitable, it is necessary to investigate their ocular toxicities and physiological interactions with cells as well as their toxicity mechanisms. The toxicity of GFNs can be extremely affected by their physicochemical properties, including composition, size, surface chemistry, and oxidation level as well as dose and the time of exposure. Up to now, there are several studies on the in vitro and in vivo toxicity of GFNs; however, a comprehensive review on ocular toxicity and applications of GFNs is missing, and a knowledge about the health risks of eye exposure to the GFNs is predominantly unspecified. This review highlights the ocular applications of GFNs and systematically covers the most recent advances of GFNs' physicochemical properties, in vitro and in vivo ocular toxicity, and the possible toxicity mechanisms as well as provides some perspectives on the potential risks of GFNs in material development and biomedical applications.

The synergistic strategies for the immuno-oncotherapy with photothermal nanoagents

Immuno-oncotherapy has shown great promise for the cure of late-stage and metastatic cancer. Great efforts have tried to improve the overall response rate (ORR) and to reduce the immune-related adverse events (irAEs). Antigen presentation, T cell activation and killing are interlocking and distinct steps to initiate effective anti-tumor immune responses. Aiming to overcome the tumor immune evasion whose mechanisms include limited release of neoantigen, suppressed infiltration of antigen-presenting cells (APCs) and T cells, and the expression of immune checkpoints (ICPs), combinational therapeutic strategies have shown great potential by activating the anti-tumor immune responses together with deactivating immunosuppressive conditions simultaneously. In this direction, photothermal therapy (PTT) has attracted attention due to the efficient ablation of tumor cells, of which the released immunogenic tumor debris can activate host immune responses. The combination of immunoadjuvants and/or ICP inhibitors can boost the anti-tumor immune responses, realizing PTT-synergized immuno-oncotherapy. In this regard, numerous multifunctional nanomaterials have been designed with integration of photothermal and immuno-oncotherapeutic agents into one package via well-designed surface modification and functionalization. This review summarizes the recent studies on the synergistic strategies for the immuno-oncotherapy based on photothermal nanoagents and the mechanisms that trigger the systemic anti-tumor immune responses and PTT-synergized immuno-oncotherapy. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Lateral size of graphene oxide determines differential cellular uptake and cell death pathways in Kupffer cells, LSECs, and hepatocytes

As a representative two-dimensional (2D) nanomaterial, graphene oxide (GO) has shown high potential in many applications due to its large surface area, high flexibility, and excellent dispersibility in aqueous solutions. These properties make GO an ideal candidate for bio-imaging, drug delivery, and cancer therapy. When delivered to the body, GO has been shown to accumulate in the liver, the primary accumulation site of systemic delivery or secondary spread from other uptake sites, and induce liver toxicity. However, the contribution of the GO physicochemical properties and individual liver cell types to this toxicity is unclear due to property variations and diverse cell types in the liver. Herein, we compare the effects of GOs with small (GO-S) and large (GO-L) lateral sizes in three major cell types in liver, Kupffer cells (KCs), liver sinusoidal endothelial cells (LSECs), and hepatocytes. While GOs induced cytotoxicity in KCs, they induced significantly less toxicity in LSECs and hepatocytes. For KCs, we found that GOs were phagocytosed that triggered NADPH oxidase mediated plasma membrane lipid peroxidation, which leads to PLC activation, calcium flux, mitochondrial ROS generation, and NLRP3 inflammasome activation. The subsequent caspase-1 activation induced IL-1β production and GSDMD-mediated pyroptosis. These effects were lateral size-dependent with GO-L showing stronger effects than GO-S. Amongst the liver cell types, decreased cell association and the absence of lipid peroxidation resulted in low cytotoxicity in LSECs and hepatocytes. Using additional GO samples with different lateral sizes, surface functionalities, or thickness, we further confirmed the differential cytotoxic effects in liver cells and the major role of GO lateral size in KUP5 pyroptosis by correlation studies. These findings delineated the GO effects on cellular uptake and cell death pathways in liver cells, and provide valuable information to further evaluate GO effects on the liver for biomedical applications.

How macrophages respond to two-dimensional materials: a critical overview focusing on toxicity

With wider use of graphene-based materials and other two-dimensional (2 D) materials in various fields, including electronics, composites, biomedicine, etc., 2 D materials can trigger undesired effects at cellular, tissue and organ level. Macrophages can be found in many organs. They are one of the most important cells in the immune system and they are relevant in the study of nanomaterials as they phagocytose them. Nanomaterials have multi-faceted effects on phagocytic immune cells like macrophages, showing signs of inflammation in the form of pro-inflammatory cytokine or reactive oxidation species production, or upregulation of activation markers due to the presence of these foreign bodies. This review is catered to researchers interested in the potential impact and toxicity of 2 D materials, particularly in macrophages, focusing on few-layer graphene, graphene oxide, graphene quantum dots, as well as other promising 2 D materials containing molybdenum, manganese, boron, phosphorus and tungsten. We describe applications relevant to the growing area of 2 D materials research, and the possible risks of ions and molecules used in the production of these promising 2 D materials, or those produced by the degradation and dissolution of 2 D materials.

Physiological and molecular responses in halotolerant Dunaliella salina exposed to molybdenum disulfide nanoparticles

Molybdenum disulfide nanoparticles (MoS₂ NPs) has emerged as the promising nanomaterial with a wide array of applications in the biomedical, industrial and environmental field. However, the potential effect of MoS₂ NPs on marine organisms has yet to be reported. In this study, the effect of MoS₂ NPs on the physiological index, subcellular morphology, transcriptomic profiles of the marine microalgae Dunaliella salina was investigated for the first time. exhibited "doping-like" effects on marine microalgae; Growth stimulation was 193.55%, and chlorophyll content increased 1.61-fold upon the addition of 50 μg/L MoS₂ NPs. Additionally, exposure to MoS₂ NPs significantly increased the protein and carbohydrate content by 2.03- and 1.56-fold, respectively. The antioxidant system was activated as well to eliminate the adverse influence of reactive oxygen species (ROS). Transcriptomic analysis revealed that genes involved in porphyrin synthesis, glycolysis/gluconeogenesis, tricarboxylic acid cycle and DNA replication were upregulated upon MoS₂ NPs exposure, which supports the mechanistic role of MoS₂ NPs in improving cellular growth and photosynthesis. The "doping-like" effects on marine algae suggest that the low concentration of MoS₂ NPs might change the rudimentary ecological composition in the ocean.

Developmental Toxicity of Few-Layered Black Phosphorus toward Zebrafish

Black phosphorus (BP) has extensive applications in various fields. The release of BP into aquatic ecosystems and the potential toxic effects on aquatic organisms are becoming major concerns. Here, we investigated the developmental toxicity of few-layered BP toward the zebrafish. We found that BP could adsorb on the surface of the chorion and could subsequently penetrate within the embryo. After exposure of embryos to 10 mg/L BP, developmental malformations appeared at 96 hpf, especially heart deformities such as pericardial edema and bradycardia, accompanied by severe circulatory system failure. Using transgenic zebrafish larvae, we further characterized cardiovascular defects with cardiac enlargement and impaired cardiac vessels as indicators of damage to the cardiovascular system upon BP exposure. We performed transcriptomic analysis on zebrafish embryos treated with a lower concentration of 2 mg/L. The results showed disruption in genes associated with muscle development, oxygen involved processes, focal adhesion, and VEGF and MAPK signaling pathways. These alterations also indicated that BP carries a risk of developmental perturbation at lower concentrations. This study provides new insights into the effects of BP on aquatic organisms.

The "Yin and Yang" of Immunomodulatory Magnesium-Enriched Graphene Oxide Nanoscrolls Decorated Biomimetic Scaffolds in Promoting Bone Regeneration

Tissue regeneration driven by immunomodulatory agents has emerged as a potential solution for repairing bone defects. However, the therapeutic benefits are compromised by disturbances in the pro- and anti-inflammatory balance. Here, using magnesium nanoparticles (MgNPs) as a template, magnesium-enriched graphene oxide nanoscrolls (MgNPs@GNSs) designed for combinational modulation of the inflammatory response are reported. First, the different effects of graphene oxide (GO) and magnesium ions (Mg²⁺ ) on Raw264.7 macrophage phenotype transformation are screened. The results reveal that GO activates inflammatory M1 macrophages, and that Mg²⁺ facilitates repolarization of M1 macrophages to the pro-healing M2 phenotype. With sustained release of Mg²⁺ , the MgNPs@GNS nanoplatform can orchestrate harmonious type 1 and type 2 inflammatory responses. Mg²⁺ decrease the internalization of GO and downregulate the nuclear factor kappa-B pathway, which is profoundly involved in the inflammatory process. A series of experiments show that the ordered inflammatory response induced by MgNPs@GNSs stimulates in vitro angiogenesis and osteogenesis through chemotactic, mitogenic, and morphogenic actions. Obvious vascularized bone regeneration is achieved in a rat cranial bone defect model via MgNPs@GNS deposited decellularized bone matrix scaffold. Therefore, the potential of using inherently therapeutic nanomedicine to modulate biomaterial-induced immune responses and thus enhance bone regeneration is demonstrated.

Graphene oxide-modified 3D acellular cartilage extracellular matrix scaffold for cartilage regeneration

Articular cartilage regeneration is a challenge in orthopedics and tissue engineering. This study prepared a graphene oxide (GO)-modified 3D acellular cartilage extracellular matrix (ACM) scaffold for cartilage repair. Cartilage slices were decellularized using a combination of physical and chemical methods of fabricating ACM particles. GO was crosslinked with the ACM by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxy succinimide to prepare a composite scaffold. GO modification improved the internal structure and mechanical properties of the scaffold. The GO-modified (2 mg/mL) composite scaffold promoted cell adhesion, cell proliferation, and chondrogenic differentiation in vitro. Experiments on subcutaneous implantation in rats demonstrated that the composite scaffold had good biocompatibility and mild inflammatory response. After 12 weeks of implantation, the composite scaffold loaded with bone marrow mesenchymal stem cells completely bridged the cartilage defects in the rabbit knee with hyaline cartilage. Results indicated that the GO-modified 3D ACM composite scaffold can provide a powerful platform for cartilage tissue engineering and articular cartilage injury treatment.

Nanomaterials for oncotherapies targeting the hallmarks of cancer

An increasing amount of evidence has demonstrated the diverse functionalities of nanomaterials in oncotherapies such as drug delivery, imaging, and killing cancer cells. This review aims to offer an authoritative guide for the development of nanomaterial-based oncotherapies and shed light on emerging yet understudied hallmarks of cancer where nanoparticles can help improve cancer control. With this aim, three nanomaterials, i.e. those based on gold, graphene, and liposome, were selected to represent and encompass metal inorganic, nonmetal inorganic, and organic nanomaterials, and four oncotherapies, i.e. phototherapies, immunotherapies, cancer stem cell therapies, and metabolic therapies, were characterized based on the differential hallmarks of cancer that they target. We also view physical plasma as a cocktail of reactive species and carrier of nanomaterials and focus on its roles in targeting the hallmarks of cancer provided with its unique traits and ability to selectively induce epigenetic and genetic modulations in cancer cells that halt tumor initiation and progression. This review provides a clear understanding of how the physico-chemical features of particles at the nanoscale contribute alone or create synergistic effects with current treatment modalities in combating each of the hallmarks of cancer that ultimately leads to desired therapeutic outcomes and shapes the toolbox for cancer control.

Mechanistic Insights into the Cytotoxicity of Graphene Oxide Derivatives in Mammalian Cells

Graphene oxide derivatives (GODs) have superb physical/chemical properties with promise for applications in biomedicine. Shape, size, and chemistry of the GODs are identified as the key parameters that impact any biological system. In this work, the GODs with a wide range of shapes (sheets, helical/longitudinal ribbons, caps, dots), sizes (10 nm to 20 μm), and chemistry (partially to fully oxidized) are synthesized, and their cytotoxicity in normal cells (NIH3T3) and colon cancer cells (HCT116) are evaluated. The mechanisms by which the GODs induce cytotoxicity are comprehensively investigated, and the toxic effects of the GODs on the NIH3T3 and the HCT116 cells are compared. While the GODs show no toxicity under the size of 50 nm, they impose moderate toxic effects at the sizes of 100 nm to 20 μm (max viability >57%). For the GODs with the similar size (100-200 nm), the helical ribbon-like structure is found to be much less toxic than the longitudinal ribbon structure (max viability 83% vs 18%) and the tubular structure (0% viability for the oxidized carbon nanotubes). It is also evident that the level of oxidation of the GOD is inversely related to the toxicity. Although the extent of GOD-induced cytotoxicity (reduction of cell viability) to the two cell lines is similar, their toxicity mechanisms are interestingly found to be substantially different. In the HCT116 cancer cells, cell membrane leakage leads to DNA damage followed by cell death, whereas in the NIH3T3 normal cells, increases in oxidative stress and physical interference between the GODs and the cells are identified as the main toxicity sources.

Immunoadjuvants for cancer immunotherapy: A review of recent developments

Cancer immunotherapy evolved as a new treatment modality to eradicate tumor cells and has gained in popularity after its successful clinical transition. By activating antigen-presenting cells (APCs), and thus, inducing innate or adaptive immune responses, immunoadjuvants have become promising tools for cancer immunotherapy. Different types of immunoadjuvants such as toll-like receptor (TLR) agonists, exosomes, and metallic and plant-derived immunoadjuvants have been studied for their immunological effects. However, the clinical use of immunoadjuvants is limited by short response rates and various side-effects. The rapid progress made in the development of nanoparticle systems as immunoadjuvant carrier vehicles has provided potential carriers for cancer immunotherapy. In this review article, we describe different types of immunoadjuvants, their limitations, modes of action, and the reasons for their clinical adoption. In addition, we review recent progress made in the nanoparticle-based immunoadjuvant field and on the combined use of nanoparticle-based immunoadjuvants and chemotherapy, phototherapy, radiation therapy, and immune checkpoint inhibitor-based therapy. STATEMENT OF SIGNIFICANCE: Cancer immunotherapy emerged as a new hope for treating malignant tumors. Different types of immunoadjuvants serve as an important tool for cancer immunotherapy by activating an innate or adaptive immune response. Limitation of free immunoadjuvant has paved the path for the development of nanoparticle-based immunoadjuvant therapy with the hope of prolonging the therapeutic efficacy. This review highlights the recent advancement made in nanoparticle-based immunoadjuvant therapy in modulating the adaptive and innate immune system. The application of the combinatorial approach of chemotherapy, phototherapy, radiation therapy adds synergy in nanoparticle-based immunoadjuvant therapy. It will broaden the reader's understanding on the recent progress made in immunotherapy with the aid of immunoadjuvant-based nanosystem.

Lentinan-Functionalized Graphene Oxide Is an Effective Antigen Delivery System That Modulates Innate Immunity and Improves Adaptive Immunity

Graphene oxide (GO) and lentinan have received great attention because of their utility in biomedical applications. Graphene oxide is utilized in drug- and vaccine-delivery systems due to its biocompatibility, large surface area, and outstanding adsorption capability, while lentinan has immunity-enhancing effects. In this study, we synthesized and characterized GO grafted with lentinan (LNT) as an adjuvant and investigated how to impact the immune responses. Lentinan-modified GO (GO-LNT) facilitated antigen uptake in macrophages and improved the efficiency of antigen application in vitro. Furthermore, in vivo, compared with GO/OVA, GO-LNT/OVA decreased the release rate of ovalbumin (OVA) to sustain long-term immune responses and boost the levels of IgG and IgG subtypes. Hence, we can infer that the effects of GO-LNT were a result of the increased amounts of antigen uptake by cells. Overall, our studies demonstrated that GO-LNT could suffice for a safe and effective vaccine-delivery system as well as an excellent adjuvant that both elicits a long-term immune memory response and potentiates cellular and humoral immunity.

Comparative Effects of Graphene and Molybdenum Disulfide on Human Macrophage Toxicity

Graphene and other 2D materials, such as molybdenum disulfide, have been increasingly used in electronics, composites, and biomedicine. In particular, MoS₂ and graphene hybrids have attracted a great interest for applications in the biomedical research, therefore stimulating a pertinent investigation on their safety in immune cells like macrophages, which commonly engulf these materials. In this study, M1 and M2 macrophage viability and activation are mainly found to be unaffected by few-layer graphene (FLG) and MoS₂ at doses up to 50 µg mL^-1 . The uptake of both materials is confirmed by transmission electron microscopy, inductively coupled plasma mass spectrometry, and inductively coupled plasma atomic emission spectroscopy. Notably, both 2D materials increase the secretion of inflammatory cytokines in M1 macrophages. At the highest dose, FLG decreases CD206 expression while MoS₂ decreases CD80 expression. CathB and CathL gene expressions are dose-dependently increased by both materials. Despite a minimal impact on the autophagic pathway, FLG is found to increase the expression of Atg5 and autophagic flux, as observed by Western blotting of LC3-II, in M1 macrophages. Overall, FLG and MoS₂ are of little toxicity in human macrophages even though they are found to trigger cell stress and inflammatory responses.

Nanotechnology as a Platform for the Development of Injectable Parenteral Formulations: A Comprehensive Review of the Know-Hows and State of the Art

Within recent decades, the development of nanotechnology has made a significant contribution to the progress of various fields of study, including the domains of medical and pharmaceutical sciences. A substantially transformed arena within the context of the latter is the development and production of various injectable parenteral formulations. Indeed, recent decades have witnessed a rapid growth of the marketed and pipeline nanotechnology-based injectable products, which is a testimony to the remarkability of the aforementioned contribution. Adjunct to the ability of nanomaterials to deliver the incorporated payloads to many different targets of interest, nanotechnology has substantially assisted to the development of many further facets of the art. Such contributions include the enhancement of the drug solubility, development of long-acting locally and systemically injectable formulations, tuning the onset of the drug’s release through the endowment of sensitivity to various internal or external stimuli, as well as adjuvancy and immune activation, which is a desirable component for injectable vaccines and immunotherapeutic formulations. The current work seeks to provide a comprehensive review of all the abovementioned contributions, along with the most recent advances made within each domain. Furthermore, recent developments within the domains of passive and active targeting will be briefly debated.

Size-Dependent Pulmonary Impact of Thin Graphene Oxide Sheets in Mice: Toward Safe-by-Design

Safety assessment of graphene-based materials (GBMs) including graphene oxide (GO) is essential for their safe use across many sectors of society. In particular, the link between specific material properties and biological effects needs to be further elucidated. Here, the effects of lateral dimensions of GO sheets in acute and chronic pulmonary responses after single intranasal instillation in mice are compared. Micrometer-sized GO induces stronger pulmonary inflammation than nanometer-sized GO, despite reduced translocation to the lungs. Genome-wide RNA sequencing also reveals distinct size-dependent effects of GO, in agreement with the histopathological results. Although large GO, but not the smallest GO, triggers the formation of granulomas that persists for up to 90 days, no pulmonary fibrosis is observed. These latter results can be partly explained by Raman imaging, which evidences the progressive biotransformation of GO into less graphitic structures. The findings demonstrate that lateral dimensions play a fundamental role in the pulmonary response to GO, and suggest that airborne exposure to micrometer-sized GO should be avoided in the production plant or applications, where aerosolized dispersions are likely to occur. These results are important toward the implementation of a safer-by-design approach for GBM products and applications, for the benefit of workers and end-users.

Applications of Graphene and Its Derivatives in the Upstream Oil and Gas Industry: A Systematic Review

Graphene and its derivatives, with their unique two-dimensional structures and excellent physical and chemical properties, have been an international research hotspot both in the research community and industry. However, in application-oriented research in the oil and gas industry they have only drawn attention in the past several years. Their excellent optical, electrical, thermal and mechanical performance make them great candidates for use in oil and gas exploration, drilling, production, and transportation. Combined with the actual requirements for well working fluids, chemical enhanced oil recovery, heavy oil recovery, profile control and water shutoff, tracers, oily wastewater treatment, pipeline corrosion prevention treatment, and tools and apparatus, etc., this paper introduces the behavior in water and toxicity to organisms of graphene and its derivatives in detail, and comprehensively reviews the research progress of graphene materials in the upstream oil and gas industry. Based on this, suggestions were put forward for the future research. This work is useful to the in-depth mechanism research and application scope broadening research in the upstream oil and gas industry.