A Review on Graphene-Based Nanomaterials in Biomedical Applications and Risks in Environment and Health

Ecotoxic impact assessment of graphene oxide on lipid peroxidation at mitochondrial level and redox modulation in fresh water fish Anabas testudineus

Rapidly expanding nanoparticle industries are predicted to have turnover of ∼$173.95 billion by 2025, indicating an urgency to study their comprehensive toxicological impact(s). Toxic effects of Graphene Oxide (GO) on oxidative stress physiology especially at mitochondrial level and redox modulation in fish in general and in climbing perch Anabas testudineus is absent. Therefore, we have investigated the toxic impacts of sub lethal doses of GO on selected oxidative stress physiology markers, protein and nucleic acid content along with haematological parameters in A. testudineus. Discriminant function and correlation analyses suggest that GO had toxic effects on the fish, as revealed from the studied parameters. Liver and gill tissues had shown strong response to GO than muscle. Augmented gradual accumulation of cellular lipid peroxides, specifically in mitochondria, was noticed. Activity of superoxide dismutase, catalase, and glutathione-S-transferase was augmented in contrast to the lowered level of the reduced glutathione titre. Alleviated total red blood corpuscle count and haemoglobin titre was parallel with an augmentation of white blood corpuscle count under GO administration. The protein level was also alleviated gradually in liver with clear changes in tissue specific nucleic acid levels, which was reduced under GO treatment. Results of the present study indicate that GO induces oxidative stress in cell and mitochondria in fish. Therefore, very careful future practices of use of GO directly, or as cargo in environmental monitoring processes in aquatic models in vitro in general and Pisces model in particular are suggested.

Self-Assembled Thin-Layer Glycomaterials With a Proper Shell Thickness for Targeted and Activatable Cell Imaging

The construction of targeted and activatable materials can largely improve the precision of disease diagnosis and therapy. However, the currently developed systems either target a transmembrane antigen or are activatable to release imaging and/or therapeutic reagents intracellularly. Here, we develop a simple thin-layer glycomaterial through the self-assembly between fluorescent glycoprobes, in which the carbohydrate-targeting reagent and the fluorophore are linked to each other by polyethylene glycol with a suitable chain length, and thin-layer manganese dioxide. The fluorogenic material developed is both capable of targeting a transmembrane glycoprotein receptor and fluorescently activatable by intracellular biothiols. The shell thickness of the material was determined to be important for achieving the biothiol-induced activation of fluorescence. This research might provide insight into the development of precision-enhanced self-assembled materials for disease theranostics.

Biocompatible N-acetyl cysteine reduces graphene oxide and persists at the surface as a green radical scavenger

We demonstrate that N-acetyl cysteine (NAC) reduces graphene oxide (GO) at room temperature. This represents a new green method to produce reduced GO (rGO). NAC adheres to the rGO surface as demonstrated by several spectroscopy techniques and avoids GO-mediated oxidation of glutathione. This method offers new opportunities for the production of green biocompatible rGO and NAC-based therapies.

Sustainability criteria for assessing nanotechnology applicability in industrial wastewater treatment: Current status and future outlook

Application of engineered nanomaterials for the treatment of industrial effluents and to deal with recalcitrant pollutants has been noticeably promoted in recent years. Laboratory, pilot and full-scale studies emphasize the potential of this technology to offer promising treatment options to meet the future needs for clean water resources and to comply with stringent environmental regulations. The technology is now in the stage of being transferred to the real applications. Therefore, the assessment of its performance according to sustainability criteria and their incorporation into the decision-making process is a key task to ensure that long term benefits are achieved from the nano-treatment technologies. In this study, the importance of sustainability criteria for the conventional and novel technologies for the treatment of industrial effluents was determined in a general approach assisted by a fuzzy-Delphi method. The criteria were categorized in technical, economic, environmental and social branches and the current situation of the nanotechnology regarding the criteria was critically discussed. The results indicate that the efficiency and safety are the most important parameters to make sustainable choices for the treatment of industrial effluents. Also, in addition to the need for scaling-up the nanotechnology in various stages, the study on their environmental footprint must continue in deeper scales under expected environmental conditions, in particular the synthesis of engineered nanomaterials and the development of reactors with the ability of recovery and reuse the nanomaterials. This paper will aid to select the most sustainable types of nanomaterials for the real applications and to guide the future studies in this field.

Synergistic Osteogenesis of Biocompatible Reduced Graphene Oxide with Methyl Vanillate in BMSCs

Methyl vanillate (MV), a recently characterized small molecule, can promote the Wnt/β-catenin signaling pathway and induce osteoblast differentiation both in vitro and in vivo. On the other hand, graphene-based materials have been introduced into the field of biomedical sciences in the past decade, and graphene oxide (GO), which serves as an efficient nanocarrier for drug delivery, has attracted great attention for its biomedical applications in tissue engineering. This study aimed to develop a biocompatible gelatin-reduced graphene oxide (GOG) for MV delivery so as to realize the effective osteogenesis for bone repair. First, GOG was prepared, and its morphology as well as properties were then characterized using scanning electron microscope (SEM), transmission electron microscopy (TEM), atomic force microscope (AFM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermal gravimetric analysis (TGA), respectively. In addition, the endocytosis of GOG in bone marrow stromal cells (BMSCs) was also investigated with the treatment of Rhodamine 6G (R6G)-labeled GOG. Our results found that GOG could be easily absorbed by cells and was distributed in both nucleus and cytoplasm, thus suggesting the favorable biocompatibility of GOG. Moreover, the effect of MV on osteogenesis was also tested, the results of which indicated that MV could promote BMSC osteogenesis in a concentration-dependent manner, and significant enhancement could be achieved at the concentration of 1 μg/mL. In addition, the complex containing different concentrations of GOG and an optimal concentration of MV was used to investigate the synergistic effect between GOG and MV on pro-osteogenesis. The results revealed that the weight ratio of MV/GOG of 1:1000 could attain remarkably enhanced osteoinduction in BMSCs, as evaluated by alkaline phosphatase (ALP) assay, alizarin red S (ARS) staining, immunofluorescence staining, and gene expression of related osteogenic markers. Taken together, these data had provided strong evidence that the complex of MV and GOG could induce osteogenesis, which was promising for bone tissue engineering.

Carbon-Based Nanomaterials for Biomedical Applications: A Recent Study

The study of carbon-based nanomaterials (CBNs) for biomedical applications has attracted great attention due to their unique chemical and physical properties including thermal, mechanical, electrical, optical and structural diversity. With the help of these intrinsic properties, CBNs, including carbon nanotubes (CNT), graphene oxide (GO), and graphene quantum dots (GQDs), have been extensively investigated in biomedical applications. This review summarizes the most recent studies in developing of CBNs for various biomedical applications including bio-sensing, drug delivery and cancer therapy.

Novel Graphene Biosensor Based on the Functionalization of Multifunctional Nano-bovine Serum Albumin for the Highly Sensitive Detection of Cancer Biomarkers

A simple, convenient, and highly sensitive bio-interface for graphene field-effect transistors (GFETs) based on multifunctional nano-denatured bovine serum albumin (nano-dBSA) functionalization was developed to target cancer biomarkers. The novel graphene-protein bioelectronic interface was constructed by heating to denature native BSA on the graphene substrate surface. The formed nano-dBSA film served as the cross-linker to immobilize monoclonal antibody against carcinoembryonic antigen (anti-CEA mAb) on the graphene channel activated by EDC and Sulfo-NHS. The nano-dBSA film worked as a self-protecting layer of graphene to prevent surface contamination by lithographic processing. The improved GFET biosensor exhibited good specificity and high sensitivity toward the target at an ultralow concentration of 337.58 fg mL^-1. The electrical detection of the binding of CEA followed the Hill model for ligand-receptor interaction, indicating the negative binding cooperativity between CEA and anti-CEA mAb with a dissociation constant of 6.82 × 10^-10 M. The multifunctional nano-dBSA functionalization can confer a new function to graphene-like 2D nanomaterials and provide a promising bio-functionalization method for clinical application in biosensing, nanomedicine, and drug delivery.

Graphene oxide touches blood: in vivo interactions of bio-coronated 2D materials

Graphene oxide is the hot topic in biomedical and pharmaceutical research of the current decade. However, its complex interactions with human blood components complicate the transition from the promising in vitro results to clinical settings. Even though graphene oxide is made with the same atoms as our organs, tissues and cells, its bi-dimensional nature causes unique interactions with blood proteins and biological membranes and can lead to severe effects like thrombogenicity and immune cell activation. In this review, we will describe the journey of graphene oxide after injection into the bloodstream, from the initial interactions with plasma proteins to the formation of the "biomolecular corona", and biodistribution. We will consider the link between the chemical properties of graphene oxide (and its functionalized/reduced derivatives), protein binding and in vivo response. We will also summarize data on biodistribution and toxicity in view of the current knowledge of the influence of the biomolecular corona on these processes. Our aim is to shed light on the unsolved problems regarding the graphene oxide corona to build the groundwork for the future development of drug delivery technology.

Biological Response to Carbon-Family Nanomaterials: Interactions at the Nano-Bio Interface

During the last few decades, several studies have suggested that carbon-based nanomaterials, owing to their unique properties, could act as promising candidates in biomedical engineering application. Wide-ranging research efforts have investigated the cellular and molecular responses to carbon-based nanomaterials at the nano-bio interfaces. In addition, a number of surface functionalization strategies have been introduced to improve their safety profile in the biological environment. The present review discusses the general principles of immunological responses to nanomaterials. Then, it explains essential physico-chemical properties of carbon-familynanomaterials, including carbon nanotubes (CNTs), graphene, fullerene, carbon quantum dots (CDs), diamond-like carbon (DLC), and mesoporous carbon biomaterials (MCNs), which significantly affect the immunological cellular and molecular responses at the nano-bio interface. The discussions also briefly highlight the recent studies that critically investigated the cellular and molecular responses to various carbon-based nanomaterials. It is expected that the most recent perspective strategies for improving the biological responses to carbon-based nanomaterials can revolutionize their functions in emerging biological applications.

Plasma and Nanomaterials: Fabrication and Biomedical Applications

Application of plasma medicine has been actively explored during last several years. Treating every type of cancer remains a difficult task for medical personnel due to the wide variety of cancer cell selectivity. Research in advanced plasma physics has led to the development of different types of non-thermal plasma devices, such as plasma jets, and dielectric barrier discharges. Non-thermal plasma generates many charged particles and reactive species when brought into contact with biological samples. The main constituents include reactive nitrogen species, reactive oxygen species, and plasma ultra-violets. These species can be applied to synthesize biologically important nanomaterials or can be used with nanomaterials for various kinds of biomedical applications to improve human health. This review reports recent updates on plasma-based synthesis of biologically important nanomaterials and synergy of plasma with nanomaterials for various kind of biological applications.

A review on graphene-based nanocomposites for electrochemical and fluorescent biosensors

Biosensors with high sensitivity, selectivity and a low limit of detection, reaching nano/picomolar concentrations of biomolecules, are important to the medical sciences and healthcare industry for evaluating physiological and metabolic parameters.

Graphene-based advanced nanoplatforms and biocomposites from environmentally friendly and biomimetic approaches

Environmentally friendly and biomimetic approaches to fabricate graphene-based advanced nanoplatforms and biocomposites for biomedical applications are summarized in this review.

A Systematic Review and Critical Analysis of the Role of Graphene-Based Nanomaterialsin Cancer Theranostics

Many graphene-based materials (GBNs) applied to therapy and diagnostics (theranostics) in cancer have been developed. Most of them are hybrid combinations of graphene with other components (e.g, drugs or other bioactives, polymers, and nanoparticles) aiming toward a synergic theranostic effect. However, the role of graphene in each of these hybrids is sometimes not clear enough and the synergic graphene effect is not proven. The objective of this review is to elaborate on the role of GBNs in the studies evaluated and to compare the nanoformulations in terms of some of their characteristics, such as therapeutic outcomes and toxicity, which are essential features for their potential use as bionanosystems. A systematic review was carried out using the following databases: PubMed, Scopus, and ISI Web of Science (2013⁻2018). Additional studies were identified manually by consulting the references list of relevant reviews. Only English papers presenting at least one strategy for cancer therapy and one strategy for cancer diagnostics, and that clearly show the role of graphene in theranostics, were included. Data extraction and quality assessment was made by reviewer pairings. Fifty-five studies met the inclusion criteria, but they were too heterogeneous to combine in statistical meta-analysis. Critical analysis and discussion of the selected papers are presented.

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.

Chemical fabrication of graphene oxide nanosheets attenuates biofilm formation of human clinical pathogens

Graphene oxide (GO) has been recently attracted considerable interest for its potential applications in physical, chemical and biological properties. In the present study, the GO nanosheets were prepared by a chemical exfoliation technique using a modified Hummers method. Initially, the prepared GO nanosheets were confirmed by UV-vis spectroscopy and further characterized by FE-SEM, Edax, HR-TEM and SAED that demonstrated the formation of GO nanosheets with few layers flat sheet structure with hexagonal lattice crystalline nature. The FTIR spectra revealed the presence of various oxygen containing functional groups has been produced from graphite plane by exfoliation technique. The prepared GO nanosheets showed excellent antibiotic resistant activity against planktonic bacteria and more effective to damage the established biofilms and inhibits the biofilm formation of human clinical pathogens like E. coli and P. aeruginosa. Further, the GO nanosheets were found to be non-toxic to normal mammalian cells and there are no apparent morphological changes were observed in control and treated cells. In conclusion, GO nanosheets were effectively preventing the formation of biofilms and kills the represent bacteria that suggested the GO nanosheets could be used for the prevention and treatment of biofilm-related infections.