In vivo toxicological evaluation of graphene oxide nanoplatelets for clinical application

The effect of graphene oxide administration on the brains of male mice: Behavioral study and assessment of oxidative stress

Graphene oxide (GO) nanoparticles are attracting growing interest in various fields, not least because of their distinct characteristics and possible uses. However, concerns about their impact on neurological health are emerging, underlining the need for in-depth studies to assess their neurotoxicity. This study examines GO exposure's neurobehavioral and biochemical effects on the central nervous system (CNS). To this end, we administered two doses of GO (2 and 5 mg/kg GO) to mice over a 46-day treatment period. We performed a battery of behavioral tests on the mice, including the open field to assess locomotor activity, the maze plus to measure anxiety, the pole test to assess balance and the rotarod to measure motor coordination. In parallel, we analyzed malondialdehyde (MDA) levels and catalase activity in the brains of mice exposed to GO nanoparticles. In addition, X-ray energy dispersive (EDX) analysis was performed to determine the molecular composition of the brain. Our observations reveal brain alterations in mice exposed to GO by intraperitoneal injection, demonstrating a dose-dependent relationship. We identified behavioral alterations in mice exposed to GO, such as increased anxiety, decreased motor coordination, reduced locomotor activity and balance disorders. These changes were dose-dependent, suggesting a correlation between the amount of GO administered and the extent of behavioral alterations. At the same time, a dose-dependent increase in malondialdehyde and catalase activity was observed, reinforcing the correlation between exposure intensity and associated biochemical responses.

Comparative toxicological analysis of two pristine carbon nanomaterials (graphene oxide and aminated graphene oxide) and their corresponding degraded forms using human in vitro models

Despite the wide application of graphene-based materials, the information of the toxicity associated to some specific derivatives such as aminated graphene oxide is scarce. Likewise, most of these studies analyse the pristine materials, while the available data regarding the harmful effects of degraded forms is very limited. In this work, the toxicity of graphene oxide (GO), aminated graphene oxide (GO-NH2), and their respective degraded forms (dGO and dGO-NH2) obtained after being submitted to high-intensity sonication was evaluated applying in vitro assays in different models of human exposure. Viability and ROS assays were performed on A549 and HT29 cells, while their skin irritation potential was tested on a reconstructed human epidermis model. The obtained results showed that GO-NH2 and dGO-NH2 substantially decrease cell viability in the lung and gastrointestinal models, being this reduction slightly higher in the cells exposed to the degraded forms. In contrast, this parameter was not affected by GO and dGO which, conversely, showed the ability to induce higher levels of ROS than the pristine and degraded aminated forms. Furthermore, none of the materials is skin irritant. Altogether, these results provide new insights about the potential harmful effects of the selected graphene-based nanomaterials in comparison with their degraded counterparts.

Short term biodistribution and in vivo toxicity assessment of intravenously injected pristine graphene oxide nanoflakes in SD rats

The present study aimed to elucidate the short term biodistribution of nano sized graphene oxide (GO) along with the toxicological assessment under in-vivo condition with an intent to analyse the toxic effects of sudden accidental exposure of GO The synthesised GO was characterized using UV-Visible spectroscopy, XRD, FTIR, Raman spectroscopy, TGA and DLS. The morphological imaging was performed using SEM, TEM and AFM. With a lateral size of less than 300 nm, these nanoparticles exhibit significant organ barrier permeability of up to 20%. Upon acute exposure to 10 mg/kg dose of ICG-tagged GO nanoflakes through intravenous route, various organs such as kidney, spleen and liver were observed, and the nanoparticles predominantly accumulated in the liver upon 24 h of exposure. Upon confirming the accumulation of these particles in liver through IVIS imaging, our next attempt was to analyse various biochemical and serum parameters. An elevation in various serum parameters such as ALT, AST, Creatinine and Bilirubin was observed. Similarly, in the case of biochemical parameters tested in liver homogenates, an increase in NO, Catalase, GSH, SOD, ROS, LPO, GR, GPx, and GST was observed. This study highlights the potential toxicological risk associated with GO exposure which must be taken into account for any risk analysis associated with GO based consumer products and the occupational hazards.

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.

Respiratory Toxicology of Graphene-Based Nanomaterials: A Review

Graphene-based nanomaterials (GBNs) consist of a single or few layers of graphene sheets or modified graphene including pristine graphene, graphene nanosheets (GNS), graphene oxide (GO), reduced graphene oxide (rGO), as well as graphene modified with various functional groups or chemicals (e.g., hydroxyl, carboxyl, and polyethylene glycol), which are frequently used in industrial and biomedical applications owing to their exceptional physicochemical properties. Given the widespread production and extensive application of GBNs, they can be disseminated in a wide range of environmental mediums, such as air, water, food, and soil. GBNs can enter the human body through various routes such as inhalation, ingestion, dermal penetration, injection, and implantation in biomedical applications, and the majority of GBNs tend to accumulate in the respiratory system. GBNs inhaled and substantially deposited in the human respiratory tract may impair lung defenses and clearance, resulting in the formation of granulomas and pulmonary fibrosis. However, the specific toxicity of the respiratory system caused by different GBNs, their influencing factors, and the underlying mechanisms remain relatively scarce. This review summarizes recent advances in the exposure, metabolism, toxicity and potential mechanisms, current limitations, and future perspectives of various GBNs in the respiratory system.

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.

Electroactive scaffolds of biodegradable polyurethane/polydopamine-functionalized graphene oxide regulating the inflammatory response and revitalizing the axonal growth cone for peripheral nerve regeneration

Long-gap peripheral nerve injury remains a major challenge in regenerative medicine and results in permanent sensory and motor dysfunction. Nerve guidance scaffolds (NGSs) are known as a promising alternative to autologous nerve grafting. The latter, the current "gold standard" in clinical practice, is frequently constrained by the limited availability of sources and the inevitable damage to the donor area. Given the electrophysiological properties of nerves, electroactive biomaterials are being intensively investigated in nerve tissue engineering. In this study, we engineered a conductive NGS compounded of biodegradable waterborne polyurethane (WPU) and polydopamine-reduced graphene oxide (pGO) for repairing impaired peripheral nerves. The incorporation of pGO at the optimal concentration (3 wt%) promoted in vitro spreading of Schwann cells (SCs) with high expression of the proliferation marker S100 protein. In an in vivo study of sciatic nerve transection injury, WPU/pGO NGSs were found to regulate the immune microenvironment by activating macrophage M2 polarization and upregulate growth-associated protein 43 (GAP43) to facilitate axonal elongation. Histological and motor function analysis demonstrated that WPU/pGO NGSs had a neuroprosthetic effect close to that of an autograft, which significantly promoted the regeneration of myelinated axons, reduced gastrocnemius atrophy, and enhanced hindlimb motor function. These findings together suggested that electroactive WPU/pGO NGSs may represent a safe and effective strategy to manage large nerve defects.

Graphene-Based Materials in Dental Applications: Antibacterial, Biocompatible, and Bone Regenerative Properties

Graphene-based materials have been shown to have advantageous properties in biomedical and dental applications due to their high mechanical, physiochemical, antibacterial, and stem cell differentiating properties. Although graphene-based materials have displayed appropriate biocompatible properties when used in implant materials for orthopedic applications, little research has been performed to specifically test the biocompatibility of graphene for dental applications. The oral environment, compared to the body, varies greatly and must be considered when evaluating biocompatibility requirements for dental applications. This review will discuss in vitro and in vivo studies that assess graphene's cytotoxicity, antibacterial properties, and cell differentiation ability to evaluate the overall biocompatibility of graphene-based materials for dental applications. Particle shape, size, and concentration were found to be major factors that affected overall biocompatibility of graphene.

Detection and modulation of neurodegenerative processes using graphene-based nanomaterials: Nanoarchitectonics and applications

Neurodegenerative disorders (NDDs) are caused by progressive loss of functional neurons following the aggregation and fibrillation of proteins in the central nervous system. The incidence rate continues to rise alarmingly worldwide, particularly in aged population, and the success of treatment remains limited to symptomatic relief. Graphene nanomaterials (GNs) have attracted immense interest on the account of their unique physicochemical and optoelectronic properties. The research over the past two decades has recognized their ability to interact with aggregation-prone neuronal proteins, regulate autophagy and modulate the electrophysiology of neuronal cells. Graphene can prevent the formation of higher order protein aggregates and facilitate the clearance of such deposits. In this review, after highlighting the role of protein fibrillation in neurodegeneration, we have discussed how GN-protein interactions can be exploited for preventing neurodegeneration. A comprehensive understanding of such interactions would contribute to the exploration of novel modalities for controlling neurodegenerative processes.

Antiviral properties of porous graphene, graphene oxide and graphene foam ultrafine fibers against Phi6 bacteriophage

As the world has experienced in the Coronavirus Disease 2019 pandemic, viral infections have devastating effects on public health. Personal protective equipment with high antiviral features has become popular among healthcare staff, researchers, immunocompromised people and more to minimize this effect. Graphene and its derivatives have been included in many antimicrobial studies due to their exceptional physicochemical properties. However, scientific studies on antiviral graphene are much more limited than antibacterial and antifungal studies. The aim of this study was to produce nanocomposite fibers with high antiviral properties that can be used for personal protective equipment and biomedical devices. In this work, 10 wt% polycaprolactone-based fibers were prepared with different concentrations (0.1, 0.5, 1, 2, 4 w/w%) of porous graphene, graphene oxide and graphene foam in acetone by using electrospinning. SEM, FTIR and XRD characterizations were applied to understand the structure of fibers and the presence of materials. According to SEM results, the mean diameters of the porous graphene, graphene oxide and graphene foam nanofibers formed were around 390, 470, and 520 nm, respectively. FTIR and XRD characterization results for 2 w/w% concentration nanofibers demonstrated the presence of graphene oxide, porous graphene and graphene foam nanomaterials in the fiber. The antiviral properties of the formed fibers were tested against Pseudomonas phage Phi6. According to the results, concentration-dependent antiviral activity was observed, and the strongest viral inhibition graphene oxide-loaded nanofibers were 33.08 ± 1.21% at the end of 24 h.

3D-Printing Graphene Scaffolds for Bone Tissue Engineering

Graphene-based materials have recently gained attention for regenerating various tissue defects including bone, nerve, cartilage, and muscle. Even though the potential of graphene-based biomaterials has been realized in tissue engineering, there are significantly many more studies reporting in vitro and in vivo data in bone tissue engineering. Graphene constructs have mainly been studied as two-dimensional (2D) substrates when biological organs are within a three-dimensional (3D) environment. Therefore, developing 3D graphene scaffolds is the next clinical standard, yet most have been fabricated as foams which limit control of consistent morphology and porosity. To overcome this issue, 3D-printing technology is revolutionizing tissue engineering, due to its speed, accuracy, reproducibility, and overall ability to personalize treatment whereby scaffolds are printed to the exact dimensions of a tissue defect. Even though various 3D-printing techniques are available, practical applications of 3D-printed graphene scaffolds are still limited. This can be attributed to variations associated with fabrication of graphene derivatives, leading to variations in cell response. This review summarizes selected works describing the different fabrication techniques for 3D scaffolds, the novelty of graphene materials, and the use of 3D-printed scaffolds of graphene-based nanoparticles for bone tissue engineering.

Graphene oxide nanoflackes prevent reperfussion injury of Langerdorff isolated rat heart providing antioxidative activity in situ

Carbon materials possess powerful antioxidant activity that might be promising for the development of new generation treatment of cardiovascular diseases, ischemic conditions, and reperfusion injury. The present study aimed to characterize the structure of nanosized graphene oxide (GrO) sample and evaluate the antioxidant efficacy of GrO in situ models of oxidative stress widely used in pre-clinical studies. The structure and surface chemistry of the initial samples were analyzed via LDS, RAMAN, LDI, TPD-MS, and FTIR methods. The GrO showed a strong ability to scavenge DPPH, hydroxyl, and superoxide anion free radicals and have a total antioxidant capacity. The DFT quantum-chemical calculation demonstrated the radical scavenging effect of GrO proceeding due to the physical adsorption of the free radical on the surface. For evaluation of the antioxidant effect of GrO in situ, we used the model of ischemia-reperfusion (I/R) of Langendorff isolated rat heart. We revealed that intravenous pretreatment of Wistar male rats with GrO significantly increased resistance of myocardium to I/R, improved restoration of heart function, prevented non-effective oxygen utilization, and I/R induced reactive oxygen species production in cardiac tissue. Thus, our data demonstrate the perspective of further use of GrO for the development of antiischemic therapy.

Characteristics of Graphene Oxide for Gene Transfection and Controlled Release in Breast Cancer Cells

Functionalized graphene oxide (GO) nanoparticles are being increasingly employed for designing modern drug delivery systems because of their high degree of functionalization, high surface area with exceptional loading capacity, and tunable dimensions. With intelligent controlled release and gene silencing capability, GO is an effective nanocarrier that permits the targeted delivery of small drug molecules, antibodies, nucleic acids, and peptides to the liquid or solid tumor sites. However, the toxicity and biocompatibility of GO-based formulations should be evaluated, as these nanomaterials may introduce aggregations or may accumulate in normal tissues while targeting tumors or malignant cells. These side effects may potentially be impacted by the dosage, exposure time, flake size, shape, functional groups, and surface charges. In this review, the strategies to deliver the nucleic acid via the functionalization of GO flakes are summarized to describe the specific targeting of liquid and solid breast tumors. In addition, we describe the current approaches aimed at optimizing the controlled release towards a reduction in GO accumulation in non-specific tissues in terms of the cytotoxicity while maximizing the drug efficacy. Finally, the challenges and future research perspectives are briefly discussed.

The Dose- and Time-Dependent Cytotoxic Effect of Graphene Nanoplatelets: In Vitro and In Vivo Study

Graphene-based nanomaterials received attention from scientists due to their unique properties: they are highly conductive, mechanically resistant and elastic. These materials can be used in different sectors of society from electronic energy storage in industry to biomedical applications. This study evaluates the influence of graphene nanoplatelets in vitro and in vivo. The toxicological influence of graphene nanoplatelets (GPs) was analyzed by cytotoxic methods, the change of cell proliferation was assessed in real-time, and the effect of GPs on a living organism was evaluated in an animal model using histopathological examination. We analyzed two types of GP administration: intratracheal and peroral. We found dose- and time-dependent cytotoxic effects of GPs in vitro; the concentration above 50 μg/mL increased the cytotoxicity significantly. The real-time analysis confirmed these data; the cells exposed to a high concentration of GPs for a longer time period resulted in a decrease in cell index which indicated lower cell viability. Histopathological examination revealed thickened alveolar septa and accumulation of GPs in the endocardium after intratracheal exposure. Peroral administration did not reveal any morphological changes. This study showed the dose- and time-dependent cytotoxic potential of graphene nanoplatelets in in vitro and in vivo models.

Novel nanocarriers for silencing anti-phagocytosis CD47 marker in acute myeloid leukemia cells

Acute myeloid leukemia (AML), a malignant disorder of Hematopoietic stem cells, can escape immunosurveillance by over expression of the cluster of differentiation 47 (CD47) marker, which functions as an inhibitory signal, suppressing phagocytosis by binding to signal regulatory protein α (SIRPα) on macrophages. AML is treated mainly by chemotherapy, which has drastic side effects and poor outcomes for the patients. Most AML patients develop drug resistance, so other methods to treat AML are highly required. Small interfering RNA (siRNA) is considered as an antitumor therapeutic due to its ability to silence genes associated with the overexpressed cancer markers and subsequently re-sensitize cancer cells. However, delivering siRNA into cells faces challenges, and the development of an effective delivery system is desired for successful silencing at the gene level. Herein, we report the usage of different formulations of graphene oxide (GO) as carriers for the delivery of CD47_siRNA (siRNA against CD47) into AML cells in vitro. The polyethylene glycol (PEG) and dendrimers (PAMAM) modified GO with small flake sizes achieved the highest silencing efficiency of the anti-phagocytosis marker CD47 gene, resulted CD47 protein down-regulation in AML cells. Moreover, the concentration at which the GO-based formulations was used has shown no cytotoxicity in AML cells or normal blood cells, which could be used to screen potential drugs for targeted gene therapy in AML.

Rapid and efficient testing of the toxicity of graphene-related materials in primary human lung cells

Graphene and its derivative materials are manufactured by numerous companies and research laboratories, during which processes they can come into contact with their handlers' physiological barriers—for instance, their respiratory system. Despite their potential toxicity, these materials have even been used in face masks to prevent COVID-19 transmission. The increasingly widespread use of these materials requires the design and implementation of appropriate, versatile, and accurate toxicological screening methods to guarantee their safety. Murine models are adequate, though limited when exploring different doses and lengths of exposure—as this increases the number of animals required, contrary to the Three R's principle in animal experimentation. This article proposes an in vitro model using primary, non-transformed normal human bronchial epithelial (NHBE) cells as an alternative to the most widely used model to date, the human lung tumor cell line A549. The model has been tested with three graphene derivatives—graphene oxide (GO), few-layer graphene (FLG), and small FLG (sFLG). We observed a cytotoxic effect (necrosis and apoptosis) at early (6- and 24-h) exposures, which intensified after seven days of contact between cells and the graphene-related materials (GRMs)—with cell death reaching 90% after a 5 µg/mL dose. A549 cells are more resistant to necrosis and apoptosis, yielding values less than half of NHBE cells at low concentrations of GRMs (between 0.05 and 5 µg/mL). Indeed, GRM-induced cell death in NHBE cells is comparable to that induced by toxic compounds such as diesel exhaust particles on the same cell line. We propose NHBE as a suitable model to test GRM-induced toxicity, allowing refinement of the dose concentrations and exposure timings for better-designed in vivo mouse assays.

Biophotonics in Dentistry

The aim of this review paper is to concentrate on the use and application of photonics in dentistry. More than one hundred review and research articles were comprehensively analysed in terms of applications of photonics in dentistry, including surgical applications, as well as dental biomaterials, diagnosis and treatments. In biomedical engineering, various fields, such as biology, chemistry, material and physics, come together in to tackle a disease/disorder either as a diagnostic tool or an option for treatment. Engineers believe that biophotonics is the application of photonics in medicine, whereas photonics is simply a technology for creating and connecting packets of light energy, known as photons. This review paper provides a comprehensive discussion of its main elements, such as photoelasticity, interferometry techniques, optical coherence tomography, different types of lasers, carbon nanotubes, graphene and quantum dots.

Nanoantibiotics to fight multidrug resistant infections by Gram-positive bacteria: hope or reality?

The spread of antimicrobial resistance in Gram-positive pathogens represents a threat to human health. To counteract the current lack of novel antibiotics, alternative antibacterial treatments have been increasingly investigated. This review covers the last decade's developments in using nanoparticles as carriers for the two classes of frontline antibiotics active on multidrug-resistant Gram-positive pathogens, i.e., glycopeptide antibiotics and daptomycin. Most of the reviewed papers deal with vancomycin nanoformulations, being teicoplanin- and daptomycin-carrying nanosystems much less investigated. Special attention is addressed to nanoantibiotics used for contrasting biofilm-associated infections. The status of the art related to nanoantibiotic toxicity is critically reviewed.

Flexible and Stretchable Bioelectronics

Medical science technology has improved tremendously over the decades with the invention of robotic surgery, gene editing, immune therapy, etc. However, scientists are now recognizing the significance of 'biological circuits' i.e., bodily innate electrical systems for the healthy functioning of the body or for any disease conditions. Therefore, the current trend in the medical field is to understand the role of these biological circuits and exploit their advantages for therapeutic purposes. Bioelectronics, devised with these aims, work by resetting, stimulating, or blocking the electrical pathways. Bioelectronics are also used to monitor the biological cues to assess the homeostasis of the body. In a way, they bridge the gap between drug-based interventions and medical devices. With this in mind, scientists are now working towards developing flexible and stretchable miniaturized bioelectronics that can easily conform to the tissue topology, are non-toxic, elicit no immune reaction, and address the issues that drugs are unable to solve. Since the bioelectronic devices that come in contact with the body or body organs need to establish an unobstructed interface with the respective site, it is crucial that those bioelectronics are not only flexible but also stretchable for constant monitoring of the biological signals. Understanding the challenges of fabricating soft stretchable devices, we review several flexible and stretchable materials used as substrate, stretchable electrical conduits and encapsulation, design modifications for stretchability, fabrication techniques, methods of signal transmission and monitoring, and the power sources for these stretchable bioelectronics. Ultimately, these bioelectronic devices can be used for wide range of applications from skin bioelectronics and biosensing devices, to neural implants for diagnostic or therapeutic purposes.

The potential of Graphene Oxide and reduced Graphene Oxide in diagnosis and treatment of Cancer

Nanotechnology is a pioneer field of study; for engineering smart nanosystems in targeted diagnosis and treatment in cancer therapy. The potent therapy for different kinds of solid tumors should ideally target individually the cancerous cells and tissue with no impact on healthy cells in the body. Nano-sized graphene oxide (GO) and reduced graphene oxide (rGO) have phenomenal chemical versatility, high surface area ratio, and supernatural physical properties. The synergistic effects caused by the well-defined assembly of GO and rGO surface generate not only essential optical, mechanical, but also electronic behaviors. Developing novel multifunctional hybrid nanoparticles with great potential is highly considered in multimodal cancer treatment. GO, and rGO are engineered as a programmable targeting delivery system and combed with photonic energy they utilize in photothermal therapy. Its remarkable properties indicated its applications as a biosensor, bio-imaging for cancer diagnosis. In this current review, we show a remarkable highlight about GO, rGO, and discuss the notable applications for cancer diagnosis and treatment, and an overview of possible cellular signaling pathways that are affected by GO, rGO in cancer treatment.

Hepatotoxicity of graphene oxide in Wistar rats

Graphene oxide (GO) has a multitude of applications in areas of nanomedicine, electronics, textile, water purification, and catalysis among others. GO is relatively easier to manufacture and customize as compared with other carbon-based nanomaterials. In the present work, GO was administered intraperitoneally to adult Wistar rats in four incremental doses, i.e., 0.0 mg/kg (control), 0.4 mg/kg (low dose), 2.0 mg/kg (mid-dose), and 10.0 mg/kg (high dose). After 15 repeated doses over a period of 30 days, biochemical assays for alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), catalase (CAT), and malondialdehyde (MDA) were carried out. Histopathological and morphometric analyses of liver and kidney were also performed. Results demonstrated dose-dependent toxicity of GO. General behavior and liver indices remained unaffected in the study. Serum levels of ALT, ALP, and AST were altered significantly in high-dose treated animals. Changes were found insignificant in the low- and mid-dose groups. Catalase activity in liver tissue homogenates was decreased in the high-dose group. MDA levels were found elevated in treated rats. Unlike control and low dose, mid- and high-dose treated rats exhibited varying degrees of histopathological changes like inflammation around the central vein and portal veins, vacuolations, hepatocytic injury, and near normal to abnormal hepatic sinusoids. These findings show that GO has considerable toxic potential to mammalian liver and thorough toxicity studies are needed before these nanosheets are used in biomedicine.

Acute administration of sulfur-doped g-C3N4 induces cognitive deficits and exacerbates the levels of glial activation in mouse hippocampus

During the last decades, graphitic carbon nitride (g-C3N4) has attracted increasing attention in several biomedical fields. In this study, the effects of sulfur-doped g-C3N4 (TCN) on cognitive function and histopathology of hippocampus were investigated in mice. The characteristics of synthetized sample were evaluated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), and energy dispersive X-ray (EDX). Twenty-four male NMRI mice received vehicle, TCN at doses of 50, 150, or 500 mg/kg via gavage for one week. Morris water maze test was done to assess the cognitive function at day 14 post TCN administration. Nissl staining was used to determine the number of dark cells in the hippocampus. Immunostaining against NeuN, GFAP, and Iba1 was done to evaluate the neuronal density and levels of glial activation, respectively. Behavioral tests indicated that TCN reduces the spatial learning and memory in a dose-dependent manner. Histological evaluations showed an increased level of neuronal loss and glial activation in the hippocampus of TCN treated mice at doses of 150 and 500 mg/kg. Overall, our data indicate that TCN induces the cognitive impairment that is partly mediated via its exacerbating impacts on neuronal loss and glial activation.

Synthesis and Toxicity of Graphene Oxide Nanoparticles: A Literature Review of In Vitro and In Vivo Studies

Nanomaterials have been widely used in many fields in the last decades, including electronics, biomedicine, cosmetics, food processing, buildings, and aeronautics. The application of these nanomaterials in the medical field could improve diagnosis, treatment, and prevention techniques. Graphene oxide (GO), an oxidized derivative of graphene, is currently used in biotechnology and medicine for cancer treatment, drug delivery, and cellular imaging. Also, GO is characterized by various physicochemical properties, including nanoscale size, high surface area, and electrical charge. However, the toxic effect of GO on living cells and organs is a limiting factor that limits its use in the medical field. Recently, numerous studies have evaluated the biocompatibility and toxicity of GO in vivo and in vitro. In general, the severity of this nanomaterial's toxic effects varies according to the administration route, the dose to be administered, the method of GO synthesis, and its physicochemical properties. This review brings together studies on the method of synthesis and structure of GO, characterization techniques, and physicochemical properties. Also, we rely on the toxicity of GO in cellular models and biological systems. Moreover, we mention the general mechanism of its toxicity.

Graphene Oxide: Opportunities and Challenges in Biomedicine

Desirable carbon allotropes such as graphene oxide (GO) have entered the field with several biomedical applications, owing to their exceptional physicochemical and biological features, including extreme strength, found to be 200 times stronger than steel; remarkable light weight; large surface-to-volume ratio; chemical stability; unparalleled thermal and electrical conductivity; and enhanced cell adhesion, proliferation, and differentiation properties. The presence of functional groups on graphene oxide (GO) enhances further interactions with other molecules. Therefore, recent studies have focused on GO-based materials (GOBMs) rather than graphene. The aim of this research was to highlight the physicochemical and biological properties of GOBMs, especially their significance to biomedical applications. The latest studies of GOBMs in biomedical applications are critically reviewed, and in vitro and preclinical studies are assessed. Furthermore, the challenges likely to be faced and prospective future potential are addressed. GOBMs, a high potential emerging material, will dominate the materials of choice in the repair and development of human organs and medical devices. There is already great interest among academics as well as in pharmaceutical and biomedical industries.

Advances on Graphene-Based Nanomaterials and Mesenchymal Stem Cell-Derived Exosomes Applied in Cutaneous Wound Healing

Graphene is a new type of carbon nanomaterial discovered after fullerene and carbon nanotube. Due to the excellent biological properties such as biocompatibility, cell proliferation stimulating, and antibacterial properties, graphene and its derivatives have become emerging candidates for the development of novel cutaneous wound dressings and composite scaffolds. On the other hand, pre-clinical research on exosomes derived from mesenchymal stem cells (MSC-Exos) has been intensified for cell-free treatment in wound healing and cutaneous regeneration, via ameliorating the damaged microenvironment of the wound site. Here, we provide a comprehensive understanding of the latest studies and observations on the various effects of graphene-based nanomaterials (GBNs) and MSC-Exos during the cutaneous wound repair process, as well as the putative mechanisms thereof. In addition, we propose the possible forward directions of GBNs and MSC-Exos applications, expecting to promote the clinical transformation.

Nanoparticle-Based Devices in the Control of Antibiotic Resistant Bacteria

Antimicrobial resistance (AR) is one of the most important public health challenges worldwide as it represents a serious complication that is able to increase the mortality, morbidity, disability, hospital stay and economic burden related to infectious diseases. As such, the spread of AR–pathogens must be considered as an emergency, and interdisciplinary approaches must be undertaken in order to develop not only drugs, but holistic strategies to undermine the epidemic and pathogenic potentials of multi-drug resistant (MDR) pathogens. One of such approaches has focused on the use of antimicrobial nanoparticles (ANPs), as they have demonstrated to possess strong antimicrobial effects on MDR pathogens. On the other hand, the ability of bacteria to develop resistance to such agents is minimal. In this way, ANPs may seem a good choice for the development of new drugs, but there is no certainty about their safety, which may delay its translation to the clinical setting. As MDR pathogens are quickly becoming more prevalent and drug development is slow and expensive, there is an increasing need for the rapid development of new strategies to control such agents. We hereby explore the possibility of designing ANP-based devices such as surgical masks and fabrics, wound dressings, catheters, prostheses, dentifrices, water filters, and nanoparticle-coated metals to exploit the potential of such materials in the combat of MDR pathogens, with a good potential for translation into the clinical setting.

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.

Graphene-Like Layers from Carbon Black: In Vivo Toxicity Assessment

Graphene-like (GL) layers, a new graphene-related material (GRM), possess peculiar chemical, colloidal, optical and transport properties. Considering the very recent promising application of GL layers in biomedical and bioelectronic fields, it is of utmost importance to investigate the toxicological profile of these nanomaterials. This study represents an important first report of a complete in vivo toxicity assessment of GL layers on embryonic zebrafish (Danio rerio). Our results show that GL layers do not lead to any perturbations in the different biological parameters evaluated, indicating their good biocompatibility on a vertebrate model. The new insight into the biosafety of GL layers will expand their applications in nanomedicine.

Evaluation of Safety and Antileishmanial Efficacy of Amine Functionalized Carbon-Based Composite Nanoparticle Appended With Amphotericin B: An in vitro and Preclinical Study

Visceral leishmaniasis (VL) has been a major health concern in the developing world, primarily affecting impoverished people. It is caused by a protozoan parasite Leishmania donovani and is characterized by immune dysfunction that can lead to deadly secondary infections. Several adverse side effects limit the existing treatment options; hence, the need of the hour is some drug option with high efficacy and no toxicity. To make targeted delivery of Amphotericin B (AmB), we have used amine-functionalized versions of carbon nanostructures, namely f-CNT and f-Graphene (f-Grap). The results with f-Grap-AmB, because of a much larger surface area, were expected to be better. However, the results obtained by us showed only marginal improvement (IC50 f-Grap-AmB; 0.0038 ± 0.00119 μg/mL). This is, in all likelihood, due to the agglomeration effect of f-Grap-AmB, which is invariably obtained with graphene. To resolve this issue, we have synthesized a graphene-CNT composite (graphene 70% and CNT 30% by weight). Because CNT is dispersed in between graphene sheets, the agglomeration effect is avoided, and our study suggests that the f-Composite-AmB (f-Comp-AmB) showed no toxicity against the murine J774A.1 macrophage cell line and did not induce any hepatic or renal toxicity in Swiss albino mice. The f-Comp-AmB also showed a remarkable elevation in the in vitro and in vivo antileishmanial efficacy in comparison to AmB and f-CNT-AmB or f-Grap-AmB in J774A.1 and Golden Syrian hamsters, respectively. Additionally, we have also observed that the percentage suppression of parasite replication in the spleen of the hamster was significantly higher in the f-Comp-AmB (97.79 ± 0.2375) treated group in comparison with the AmB (85.66 ± 1.164) treated group of hamsters. To conclude, f-Comp-AmB could be a safe and reliable therapeutic option over the other carbon-based nanoparticles (NPs), i.e., f-CNT-AmB, f-Grap-AmB, and conventional AmB.

Investigations of conformational structure and enzymatic activity of trypsin after its binding interaction with graphene oxide

Herein, interaction between graphene oxide (GO) and trypsin was systematically characterized for deep investigations of conformational structure and enzymatic activity of trypsin affected by GO. Results indicated that GO bound with trypsin to form ground state complex with molar ratio of 1 to 1. Intrinsic fluorescence of trypsin was statically quenched by GO through van der Waal interaction, hydrophobic interaction, hydrogen bond, and electrostatic interaction. Both tertiary structure and secondary structure of trypsin were changed obviously after its binding with trypsin, resulting in the structure transformation of trypsin from the β-sheet structure to the α-helix structure. Since GO bound with the allosteric site of trypsin to inhibit its enzymatic activity via non-competitive manner, GO efficiently protected human serum albumin and human cervical carcinoma HeLa cells from the digestion of trypsin. These results explored the exact binding mechanism of GO with protease, which provides more important information for possible biological risk of GO on human beings.

Graphene Oxide-Based Nanomaterials: An Insight into Retinal Prosthesis

Retinal prosthesis has recently emerged as a treatment strategy for retinopathies, providing excellent assistance in the treatment of age-related macular degeneration (AMD) and retinitis pigmentosa. The potential application of graphene oxide (GO), a highly biocompatible nanomaterial with superior physicochemical properties, in the fabrication of electrodes for retinal prosthesis, is reviewed in this article. This review integrates insights from biological medicine and nanotechnology, with electronic and electrical engineering technological breakthroughs, and aims to highlight innovative objectives in developing biomedical applications of retinal prosthesis.

Applications of Nanotechnology in Sensor-Based Detection of Foodborne Pathogens

The intake of microbial-contaminated food poses severe health issues due to the outbreaks of stern food-borne diseases. Therefore, there is a need for precise detection and identification of pathogenic microbes and toxins in food to prevent these concerns. Thus, understanding the concept of biosensing has enabled researchers to develop nanobiosensors with different nanomaterials and composites to improve the sensitivity as well as the specificity of pathogen detection. The application of nanomaterials has enabled researchers to use advanced technologies in biosensors for the transfer of signals to enhance their efficiency and sensitivity. Nanomaterials like carbon nanotubes, magnetic and gold, dendrimers, graphene nanomaterials and quantum dots are predominantly used for developing biosensors with improved specificity and sensitivity of detection due to their exclusive chemical, magnetic, mechanical, optical and physical properties. All nanoparticles and new composites used in biosensors need to be classified and categorized for their enhanced performance, quick detection, and unobtrusive and effective use in foodborne analysis. Hence, this review intends to summarize the different sensing methods used in foodborne pathogen detection, their design, working principle and advances in sensing systems.

Graphene oxide-induced neurotoxicity on neurotransmitters, AFD neurons and locomotive behavior in Caenorhabditis elegans

Graphene oxide (GO) and graphene-based nanomaterials have been widely applied in recent years, but their potential health risk and neurotoxic potentials remain poorly understood. In this study, neurotoxic potential of GO and its underlying molecular and cellular mechanism were investigated using the nematode, Caenorhabditis elegans. Deposition of GO in the head region and increased reactive oxygen species (ROS) was observed in C. elegans after exposure to GO. The neurotoxic potential of GO was then investigated, focusing on neurotransmitters contents and neuronal activity using AFD sensory neurons. The contents of all neurotransmitters, such as, tyrosine, tryptophan, dopamine, tyramine, and GABA, decreased significantly by GO exposure. Decreased fluorescence of Pgcy-8:GFP, a marker of AFD sensory neuron, by GO exposure suggested GO could cause neuronal damage on AFD neuron. GO exposure led decreased expression of ttx-1 and ceh-14, genes required for the function of AFD neurons also confirmed possible detrimental effect of GO to AFD neuron. To understand physiological meaning of AFD neuronal damage by GO exposure, locomotive behavior was then investigated in wild-type as well as in loss-of-function mutants of ttx-1 and ceh-14. GO exposure significantly altered locomotor behavior markers, such as, speed, acceleration, stop time, etc., in wild-type C. elegans, which were mostly rescued in AFD neuron mutants. The present study suggested the GO possesses neurotoxic potential, especially on neurotransmitters and AFD neuron in C. elegans. These findings provide useful information to understand the neurotoxic potential of GO and other graphene-based nanomaterials, which will guide their safe application.

Graphene Oxide: A Smart (Starting) Material for Natural Methylxanthines Adsorption and Detection

Natural methylxanthines, caffeine, theophylline and theobromine, are widespread biologically active alkaloids in human nutrition, found mainly in beverages (coffee, tea, cocoa, energy drinks, etc.). Their detection is thus of extreme importance, and many studies are devoted to this topic. During the last decade, graphene oxide (GO) and reduced graphene oxide (RGO) gained popularity as constituents of sensors (chemical, electrochemical and biosensors) for methylxanthines. The main advantages of GO and RGO with respect to graphene are the easiness and cheapness of synthesis, the notable higher solubility in polar solvents (water, among others), and the higher reactivity towards these targets (mainly due to - interactions); one of the main disadvantages is the lower electrical conductivity, especially when using them in electrochemical sensors. Nonetheless, their use in sensors is becoming more and more common, with the obtainment of very good results in terms of selectivity and sensitivity (up to 5.4 × 10-10 mol L-1 and 1.8 × 10-9 mol L-1 for caffeine and theophylline, respectively). Moreover, the ability of GO to protect DNA and RNA from enzymatic digestion renders it one of the best candidates for biosensors based on these nucleic acids. This is an up-to-date review of the use of GO and RGO in sensors.

Well-defined Graphene Oxide as a Potential Component in Lung Cancer Therapy

BACKGROUND

Graphene oxide (GO) has unique physical and chemical properties that can be used in anticancer therapy - especially as a drug carrier. Graphene oxide, due to the presence of several hybrid layers of carbon atoms (sp2), has a large surface for highly efficient drug loading. In addition, GO with a large number of carboxyl, hydroxyl and epoxy groups on its surface, can charge various drug molecules through covalent bonds, hydrophobic interactions, hydrogen bonds and electrostatic interactions.

OBJECTIVE

The aim of our work was to evaluate the possibility of future use of graphene oxide as an anticancer drug carrier.

METHODS

In this paper, we present GO synthesis and characterization, as well as a study of its biological properties. The cytotoxic effect of well-defined graphene oxide was tested on both carcinoma and non-malignant cells isolated from the same organ, which is not often presented in the literature.

RESULTS

The performed research confirmed that GO in high concentrations (> 300 µgmL-1) selectively decreased the viability of cancer cell line. Additionally, we showed that the GO flakes have a high affinity to cancer cell nucleus which influences their metabolism (inhibition of cancer cell proliferation). Moreover, we have proved that GO in high concentrations can cause cell membrane damage and generate reactive oxygen species on a low level mainly in cancer cells.

CONCLUSION

The proposed GO could be useful in anticancer therapy. A high concentration of GO selectively causes the death of tumor cells, whereas GO with low concentration could be a potential material for anticancer drug loading.

Induction of chromosomal and DNA damage and histological alterations by graphene oxide nanoparticles in Swiss mice

The unique physicochemical properties of graphene oxide (GO) nanoparticles increase their uses in a wide range of applications that increase their release into the environment, and thus human exposure. However, the in vivo clastogenicity and genotoxicity of GO nanoparticles have not been well investigated. The current study was, therefore, designed to investigate the possible induction of chromosomal and DNA damage by GO nanoparticles and their impact on the tissue architecture in mice. Oral administration of GO nanoparticles for one or five consecutive days at the three dose levels 10, 20 or 40 mg/kg significantly increased the micronuclei and DNA damage levels in a dose-dependent manner in mice bone marrow cells, as well as caused, histological lesions including apoptosis, necrosis, inflammations and cells degeneration in the mice liver and brain tissue sections compared to the normal control mice. Thus, we concluded that oral administration of GO nanoparticles induced chromosomal and DNA damage in a dose-dependent manner as well as histological injuries in both acute and subacute treatments.

Graphene Nanomaterials: Synthesis, Biocompatibility, and Cytotoxicity

Graphene, graphene oxide, and reduced graphene oxide have been widely considered as promising candidates for industrial and biomedical applications due to their exceptionally high mechanical stiffness and strength, excellent electrical conductivity, high optical transparency, and good biocompatibility. In this article, we reviewed several techniques that are available for the synthesis of graphene-based nanomaterials, and discussed the biocompatibility and toxicity of such nanomaterials upon exposure to mammalian cells under in vitro and in vivo conditions. Various synthesis strategies have been developed for their fabrication, generating graphene nanomaterials with different chemical and physical properties. As such, their interactions with cells and organs are altered accordingly. Conflicting results relating biocompatibility and cytotoxicity induced by graphene nanomaterials have been reported in the literature. In particular, graphene nanomaterials that are used for in vitro cell culture and in vivo animal models may contain toxic chemical residuals, thereby interfering graphene-cell interactions and complicating interpretation of experimental results. Synthesized techniques, such as liquid phase exfoliation and wet chemical oxidation, often required toxic organic solvents, surfactants, strong acids, and oxidants for exfoliating graphite flakes. Those organic molecules and inorganic impurities that are retained in final graphene products can interact with biological cells and tissues, inducing toxicity or causing cell death eventually. The residual contaminants can cause a higher risk of graphene-induced toxicity in biological cells. This adverse effect may be partly responsible for the discrepancies between various studies in the literature.