Graphene Nanomaterials Research Articles

Design of a new label free active biosensor based on metallic nanoparticles-doped graphene nanodisk platform

The advantage of graphene nanomaterial to support strong plasmonic resonances in the THz frequency range makes it an ideal candidate in biosensing field where the ability of detecting molecules is becoming essential to improve the quality of human life. In this paper, a theoretical study of plasmon nanosensor based on silver metallic nanoparticles (Ag MNPs) placed near the surface of graphene nanodisk (GND) for blood components detection is analyzed and then the results are presented. The exploited nonlinear Kerr effect shows that the sensitivity (Se) is equal to 472 (nm/RIU) in THz frequency range while the selectivity (θ) is around 19.6 RIU−1. The proposed biosensor is characterized by a wide linear range sensor between 0.02mM–0.054 mM and a limit of detection (LoD) around 0.018 mM. It is mentioned that the chemical potential (μ) and the temperature (T) of graphene nanodisk essentially control the sensitivity of the proposed biosensor which represents a fundamental feature in optical sensor processing and leverages the CMOS compatibility necessary for various biological compounds detection.

Bimetallic nitrogen-doped porous graphene for highly efficient magnetic solid phase extraction of 5-nitroimidazoles in environmental water

In this work, Fe/Ni bimetallic nitrogen-doped porous graphene (Fe/Ni-NPG) nanomaterials with rich pores, strong magnetism and good reusability were successfully prepared by one-step combustion and can be used as magnetic solid phase extraction (MSPE) adsorbents for the determination of 5-nitroimidazoles (5-NDZs) in environmental water samples. The dispersion and active sites of the materials were increased by the introduction of nitrogen. The adsorption behavior of Fe/Ni-NPG for 5-NDZs was investigated, which corresponds to the quasi-second-order kinetics and Langmuir adsorption model. The π-π electron donor-acceptor interaction (π-π EDA), hydrogen bond and electrostatic interaction between Fe/Ni-NPG and 5-NDZs are the main factors that help to obtain excellent adsorption properties. Several important conditions of MSPE are systematically optimized. Under the optimal MSPE conditions, the linear range of DMZ was 0.6–500 μg/L, the linear range of TNZ and ONZ was 0.7–500 μg/L, and the correlation coefficient R2 ≥ 0.9991. The limit of detection was 0.18–0.2 μg/L, the limit of quantification was 0.6–0.7 μg/L, and the RSDs of intraday and interday precision were 1.58%–4.66% and 3.77–9.69%, respectively. In the three spiked actual environmental water samples, the recovery was 78.05%–107.05% (RSDs<7.82%). The results show that this method based on Fe/Ni-NPG provides an accurate and reliable way to detect 5-NDZs in environmental water.

Recent Trends in Graphene/Polymer Nanocomposites for Sensing Devices: Synthesis and Applications in Environmental and Human Health Monitoring.

Graphene-based nanocomposites are largely explored for the development of sensing devices due to the excellent electrical and mechanical properties of graphene. These properties, in addition to its large specific surface area, make graphene attractive for a wide range of chemical functionalization and immobilization of (bio)molecules. Several techniques based on both top-down and bottom-up approaches are available for the fabrication of graphene fillers in pristine and functionalized forms. These fillers can be further modified to enhance their integration with polymeric matrices and substrates and to tailor the sensing efficiency of the overall nanocomposite material. In this review article, we summarize recent trends in the design and fabrication of graphene/polymer nanocomposites (GPNs) with sensing properties that can be successfully applied in environmental and human health monitoring. Functional GPNs with sensing ability towards gas molecules, humidity, and ultraviolet radiation can be generated using graphene nanosheets decorated with metallic or metal oxide nanoparticles. These nanocomposites were shown to be effective in the detection of ammonia, benzene/toluene gases, and water vapor in the environment. In addition, biological analytes with broad implications for human health, such as nucleic bases or viral genes, can also be detected using sensitive, graphene-based polymer nanocomposites. Here, the role of the biomolecules that are immobilized on the graphene nanomaterial as target for sensing is reviewed.

Recent Progress in Graphene- and Related Carbon-Nanomaterial-based Electrochemical Biosensors for Early Disease Detection.

Graphene- and carbon-based nanomaterials are key materials to develop advanced biosensors for the sensitive detection of many biomarkers owing to their unique properties. Biosensors have attracted increasing interest because they allow efficacious, sensitive, selective, rapid, and low-cost diagnosis. Biosensors are analytical devices based on receptors for the process of detection and transducers for response measuring. Biosensors can be based on electrochemical, piezoelectric, thermal, and optical transduction mechanisms. Early virus identification provides critical information about potentially effective and selective therapies, extends the therapeutic window, and thereby reduces morbidity. The sensitivity and selectivity of graphene can be amended via functionalizing it or conjoining it with further materials. Amendment of the optical and electrical features of the hybrid structure by introducing appropriate functional groups or counterparts is especially appealing for quick and easy-to-use virus detection. Various techniques for the electrochemical detection of viruses depending on antigen-antibody interactions or DNA hybridization are discussed in this work, and the reasons behind using graphene and related carbon nanomaterials for the fabrication are presented and discussed. We review the existing state-of-the-art directions of graphene-based classifications for detecting DNA, protein, and hormone biomarkers and summarize the use of the different biosensors to detect several diseases, like cancer, Alzheimer's disease, and diabetes, to sense numerous viruses, including SARS-CoV-2, human immunodeficiency virus, rotavirus, Zika virus, and hepatitis B virus, and to detect the recent pandemic virus COVID-19. The general concepts, mechanisms of action, benefits, and disadvantages of advanced virus biosensors are discussed to afford beneficial evidence of the creation and manufacture of innovative virus biosensors. We emphasize that graphene-based nanomaterials are ideal candidates for electrochemical biosensor engineering due to their special and tunable physicochemical properties.

Research Status of Graphene Polyurethane Composite Coating

Graphene material has a variety of excellent properties and applications in energy storage, biomaterials, photoelectric devices, and other fields. With the progress of nanotechnology, graphene nanomaterials have shown their advantages in the field of new nano-corrosion coatings with their high barrier structure. In addition, polyurethane is also widely used in the field of anti-corrosion coatings due to its excellent chemical resistance, mechanical properties, and weathering resistance. The preparation of composite coatings by combining graphene nanomaterials with traditional polyurethane (PU) coatings has opened up a new way for the research and development of new anticorrotic coatings. In this paper, graphene polyurethane composite coating was first used as the research object, and the mechanism of graphene material in the new composite coating was analyzed. Then, graphene oxide (GO), a commonly used precursor material, was used as an entry point for a detailed study of the properties of GO materials and the advantages and disadvantages of its application in composites, and two types of modifications, covalent and non-covalent, were analyzed. In addition, the preparation methods and processes of graphene polyurethane composite coatings were summarized. Finally, the future research directions and research focus of GO were prospected.

Fluorinated graphene nanomaterial causes potential mechanical perturbations to a biomembrane.

Fluorinated graphene (F-GRA) has attracted great interest in biomedical applications. In this context, the direct interaction between F-GRA and various biomolecules is a vital process guiding the bio-function of this nanomaterial. Nevertheless, information regarding the interaction of F-GRA with biomolecules is scarce, particularly at the molecular level. In this study, using an in silico approach, we investigate the adsorption of F-GRA to a phospholipid bilayer to evaluate the potential effect of the nanomaterial to a biomembrane and its mechanism. Our results indicate that F-GRA can either slightly insert into the membrane or parallelly adhere on the membrane surface, different from the complete insertion of graphene. Detailed analysis confirms that the electrostatic forces dominantly mediate the adsorption process. F-GRA in its parallel binding pattern causes a partial enlargement in the membrane thickness via the disruption of the lipids' order parameters, indicating a mild mechanical influence to the membrane structure. Although the potential mechanical perturbation of F-GRA to membrane is detected, this impact is much weaker than graphene. These findings suggest the potentially weak physical perturbations of F-GRA to the cellular membrane, which may establish the basis for the future biomedical applications of this material after proper surface coating.

Effect of Graphene Oxide on the Low-Temperature Crack Resistance of Polyurethane-SBS-Modified Asphalt and Asphalt Mixtures.

In this study, the novel nanomaterial graphene oxide (GO) was added as a modifier to polyurethane–styrene-butadiene-styrene (SBS)-modified asphalt, and a graphene oxide/polyurethane/SBS composite-modified asphalt mix was prepared. The effect of the graphene oxide material on the low-temperature crack resistance of the asphalt and mixes was investigated by bending beam rheometer (BBR) tests, beamlet bending tests at different low temperatures, and characterization by scanning electron microscopy for its microscopic condition. OpenCV image processing was used to visually represent the low-temperature cracking of the mix. The results of the BBR tests showed that the incorporation of graphene oxide resulted in a reduction in creep stiffness S and an increase in creep rate m compared with the control asphalt. The best improvement in the low-temperature cracking resistance of the polyurethane/SBS-modified asphalt was achieved at 0.5% GO doping. The results of the small beam flexural tests showed that graphene oxide as a modifier improved the flexural strength and flexural strain of the mix, resulting in a mix with a lower stiffness modulus and a better relaxation stress capacity with the addition of graphene oxide, which is also expressed through the OpenCV images. Graphene oxide significantly improved the low-temperature crack resistance of polyurethane-SBS-modified asphalt and its mixes. As a new type of nanomaterial-modified asphalt, graphene oxide/polyurethane/SBS composite-modified asphalt shows promising applicability in cold zone roads.

A state-of-the-art review on graphene-based nanomaterials to determine antibiotics by electrochemical techniques

Antibiotics might build up into the human body by foodstuff metabolism, posing a serious threat to human health and safety. Establishing simple and sensitive technology for quick antibiotic evaluation is thus extremely important. Nanomaterials (or NMTs) with the advantage of possessing merits such as remarkable optical, thermal, mechanical, and electrical capabilities have been highlighted as a piece of the best promising materials for rising new paths in the creation of the future generation biosensors. This paper presents the most recent advances in the use of graphene NMTs-based biosensors to determine antibiotics. Gr-NMTs (or graphene nanomaterials) have been used in the development of a biosensor for the electrochemical signal-transducing process. The rising issues and potential chances of this field are contained to give a plan for forthcoming research orientations. As a result, this review provides a comprehensive evaluation of the nanostructured electrochemical sensing approach for antibiotic residues in various systems. In this review, various electrochemical techniques such as CV, DPV, Stripping, EIS, LSV, chronoamperometry, SWV were employed to determine antibiotics. Additionally, this also demonstrates how graphene nanomaterials are employed to detect antibiotics.

Self-assembly and photoinduced fabrication of conductive nanographene wires on boron nitride

Manufacturing molecule-based functional elements directly at device interfaces is a frontier in bottom-up materials engineering. A longstanding challenge in the field is the covalent stabilization of pre-assembled molecular architectures to afford nanodevice components. Here, we employ the controlled supramolecular self-assembly of anthracene derivatives on a hexagonal boron nitride sheet, to generate nanographene wires through photo-crosslinking and thermal annealing. Specifically, we demonstrate µm-long nanowires with an average width of 200 nm, electrical conductivities of 106 S m−1 and breakdown current densities of 1011 A m−2. Joint experiments and simulations reveal that hierarchical self-assembly promotes their formation and functional properties. Our approach demonstrates the feasibility of combined bottom-up supramolecular templating and top-down manufacturing protocols for graphene nanomaterials and interconnects, towards integrated carbon nanodevices.

Large-Scale Syntheses of 2D Materials: Flash Joule Heating and Other Methods.

In the past 17 years, the larger-scale production of graphene and graphene family materials has proven difficult and costly, thus slowing wider-scale commercial applications. The quality of the graphene that is prepared on larger scales has often been poor, demonstrating a need for improved quality controls. Here, current industrial graphene synthetic and analytical methods, as well as recent academic advancements in larger-scale or sustainable synthesis of graphene, defined here as weights more than 200 mg or films larger than 200 cm2 , are compiled and reviewed. There is a specific emphasis on recent research in the use of flash Joule heating as a rapid, efficient, and scalable method to produce graphene and other 2D nanomaterials. Reactor design, synthetic strategies, safety considerations, feedstock selection, Raman spectroscopy, and future outlooks for flash Joule heating syntheses are presented. To conclude, the remaining challenges and opportunities in the larger-scale synthesis of graphene and a perspective on the broader use of flash Joule heating for larger-scale 2D materials synthesis are discussed.

Immobilization of Air-Stable Copper Nanoparticles on Graphene Oxide Flexible Hybrid Films for Smart Clothes.

Through the use of organic/inorganic hybrid dispersants—which are composed of polymeric dispersant and two-dimension nanomaterial graphene oxide (GO)—copper nanoparticles (CuNPs) were found to exhibit nano stability, air-stable characteristics, as well as long-term conductive stability. The polymeric dispersant consists of branched poly(oxyethylene)-segmented esters of trimellitic anhydride adduct (polyethylene glycol−trimethylolpropane−trimellitic anhydride, designated as PTT). PTT acts as a stabilizer for CuNPs, which are synthesized via in situ polymerization and redox reaction of the precursor Cu(CH3COO)2 within an aqueous system, and use graphene oxide to avoid the reduction reaction of CuNPs. The results show that after 30 days of storage the CuNPs/PTT/GO composite film maintains a highly conductive network (9.06 × 10−1 Ω/sq). These results indicate that organic/inorganic PTT/GO hybrid dispersants can effectively maintain the conductivity stability of CuNPs and address the problem of CuNP oxidation. Finally, the new CuNPs/PTT/GO composite film was applied to the electrocardiogram (ECG) smart clothes. This way, a stable and antioxidant-sensing electrode can be produced, which is expected to serve as a long-term ECG monitoring device.

Non-homogeneous dispersion of graphene in polyacrylonitrile substrates induces a migrastatic response and epithelial-like differentiation in MCF7 breast cancer cells

BackgroundRecent advances from studies of graphene and graphene-based derivatives have highlighted the great potential of these nanomaterials as migrastatic agents with the ability to modulate tumor microenvironments. Nevertheless, the administration of graphene nanomaterials in suspensions in vivo is controversial. As an alternative approach, herein, we report the immobilization of high concentrations of graphene nanoplatelets in polyacrylonitrile film substrates (named PAN/G10) and evaluate their potential use as migrastatic agents on cancer cells.ResultsBreast cancer MCF7 cells cultured on PAN/G10 substrates presented features resembling mesenchymal-to-epithelial transition, e.g., (i) inhibition of migratory activity; (ii) activation of the expression of E-cadherin, cytokeratin 18, ZO-1 and EpCAM, four key molecular markers of epithelial differentiation; (iii) formation of adherens junctions with clustering and adhesion of cancer cells in aggregates or islets, and (iv) reorganization of the actin cytoskeleton resulting in a polygonal cell shape. Remarkably, assessment with Raman spectroscopy revealed that the above-mentioned events were produced when MCF7 cells were preferentially located on top of graphene-rich regions of the PAN/G10 substrates.ConclusionsThe present data demonstrate the capacity of these composite substrates to induce an epithelial-like differentiation in MCF7 breast cancer cells, resulting in a migrastatic effect without any chemical agent-mediated signaling. Future works will aim to thoroughly evaluate the mechanisms of how PAN/G10 substrates trigger these responses in cancer cells and their potential use as antimetastatics for the treatment of solid cancers.Graphical

Cost Effective Synthesis of Graphene Nanomaterials for Non-Enzymatic Electrochemical Sensors for Glucose: A Comprehensive Review.

The high conductivity of graphene material (or its derivatives) and its very large surface area enhance the direct electron transfer, improving non-enzymatic electrochemical sensors sensitivity and its other characteristics. The offered large pores facilitate analyte transport enabling glucose detection even at very low concentration values. In the current review paper we classified the enzymeless graphene-based glucose electrocatalysts’ synthesis methods that have been followed into the last few years into four main categories: (i) direct growth of graphene (or oxides) on metallic substrates, (ii) in-situ growth of metallic nanoparticles into graphene (or oxides) matrix, (iii) laser-induced graphene electrodes and (iv) polymer functionalized graphene (or oxides) electrodes. The increment of the specific surface area and the high degree reduction of the electrode internal resistance were recognized as their common targets. Analyzing glucose electrooxidation mechanism over Cu- Co- and Ni-(oxide)/graphene (or derivative) electrocatalysts, we deduced that glucose electrochemical sensing properties, such as sensitivity, detection limit and linear detection limit, totally depend on the route of the mass and charge transport between metal(II)/metal(III); and so both (specific area and internal resistance) should have the optimum values.

Generate high data rate of optical carries by using nanomaterial graphene in slab waveguide

Abstract Single mode is one of the most practical applications in microwave propagations because of its high mode resolution and low transmission loss. In this paper, the single mode graphene material was implemented in slab waveguide to study the performance and optical properties of graphene material; the parameters that affect these models were found to be the cut-off frequency, attenuation wavenumbers, modes numbers, skin depth, angles incident, and propagation wave numbers. The effectiveness of these factors was simulated and analyzed using MATLAB software program. In this paper, the carriers were generated using nano-graphene; the optical carrier source provided seven carriers with the frequency spacing of 4.9682 GHz. After splitting the carriers using optical demultiplexer, these carriers were modulated independently using optical Quadrature phase shift keying (QPSK) modulators at symbol rate equal to 4.9682 Gsymbol/s; this matches the frequency spacing of the carriers. Under this argument, the total data rate was equal to 2*7*4.9682 Gsymbol/s = 69.5548 Gbit/s, and the total bandwidth was 34.774 GHz. These carriers were found to work in optical communication with high data rate.

Application of Graphene: A Nanostar in the World of Dentistry

Graphene and graphene-based nanomaterials have recently gained interest in nanomedicine as well as in dentistry. They have excellent mechanical electrical and thermal properties. This review discusses various applications of graphene and its derivatives in the field of dentistry including denture base materials restorative materials implants bone regeneration and oral cancer

Simulação da gênese de grafeno geológico por aparato pistão-cilindro

Stable natural graphene occurs in graphite- and phyllosilicate-bearing low-grade metamorphic rocks. The present work simulates the process of geological formation of graphene using a piston-cylinder apparatus, promoting diffusion between talc and graphite at 700ºC and 900 MPa for a period of 24 h. The experimental products were analyzed by optical and scanning electron microscopy for description of the microstructures formed between the mineral precursors. The talc-graphite diffusion zone was also analyzed by Raman spectroscopy. Results indicate that graphite becomes progressively more deformed near the talc diffusion zone and eventually undergoes cleavage. Graphene becomes stable on the talc substrate in the center of diffusion zone. Therefore, the search for deposits of natural graphene and other nanomaterials in geological context is promising.

Neurotrophic factors combined with ordered collagen nano-modified materials in the recovery of exercise ability of patients with peripheral nerve transection

This study was to analyse the application of neurotrophic factor (NTF) combined with ordered collagen modified material (OCMM) (taking graphene oxide (GO) as example) modified nanofibre stent (NFS) in the recovery of exercise ability of patients with peripheral nerve transection (PNT). The graphene NFS was prepared by dissolving the graphite powder to prepare graphene nanomaterials by ultrasonic and centrifugal treatment methods. It showed that the NFS was successfully modified and had good mechanical properties, hydrophilicity, and biocompatibility. In addition, the nanofibre material (NFM) can effectively enhance the migration and proliferation of neuronal cells, thereby promoting nerve regeneration and exercise recovery in patients with nerve injury.

Binding Peptide-Promoted Biofunctionalization of Graphene Paper with Hydroxyapatite for Stimulating Osteogenic Differentiation of Mesenchymal Stem Cells.

Graphene paper (GP), a macroscopic self-supporting material, has exceptional flexibility and preserves the excellent physical and chemical properties of graphene nanomaterials. But its applications in regenerative medicine remain to be further explored. Here, we biologically functionalized GP with hydroxyapatite (HA) nanorods by the use of GP-binding peptides as an affinity linker. This strategy solved two daunting challenges for regenerative medicine applications of GP: the lack of good hydrophilicity for supporting cell growth and the difficulty in forming composites by binding with nanobiomaterials. Briefly, we first screened a high-affinity GP-binding peptide (TWWNPRLVYFDY) by the phage display technique. Then we chemically conjugated the GP-binding peptide to the synthetic HA nanorods. The GP-binding peptide on the resultant HA nanorods enabled them to be bound and assembled onto the GP substrate with high affinity, forming a GP-peptide-HA composite with significantly improved hydrophilicity of GP. The composite promoted the attachment and proliferation of mesenchymal stem cells (MSCs), demonstrating its outstanding biocompatibility. Due to the unique compositions of the composite, it was also found to induce osteogenic differentiation of MSCs in vitro in the absence of other inducers in the medium, by verifying the expression of the osteogenic markers including collagen-1, bone morphogenetic proteins 2, runx-related transcription factor 2, osteocalcin, and alkaline phosphatase. Our work suggests that the GP-binding peptide can be used to link inorganic nanoparticles onto GP to facilitate the biomedical applications of GP.

A Review of the State of the Art towards Biological Applications of Graphene-based Nanomaterials

The field of nanoscience has evolved into a wide variety of successes over the past two decades and the emphasis on nanotechnology is to revolve around various dynamic fields, such as sensor, biomedical, and many useful applications. Advances in related fields are certainly due to the ability to synthesize nanoparticles from a variety of materials, structures, and to convert samples into complex nanoarchitectures. The promises of nanomedicine are broad. Graphene (Gr), the first 2-dimensional material to stand alone, is a type of new nanomaterial that leads to the excitement of natural biological applications. Number of researches has been conducted on applicability of GBNs in the area of environment, biomedical, and healthcare sectors. As compared to other nanomaterials, extraordinary properties of graphene-based nanomaterials (GBNs) like high surface area, multilayers, multifunctional and excellent biocompatibility make them capable to play great roll of highly-tailored multifunctional delivery vehicles for drugs delivery, gene delivery, phototherapy and bioimaging. However, research communities performed plenty of research works on GBNs synthesis and biological acitivity evaluation, but there is limited comprehensive reviews published so far biological applications. So, we have studied a large number of scientific reports and investigations, presented in this review describing recent progress and modern perspectives with respect to graphene and related nanomaterials for biological applications.

The effect of N-doping on the electronic structure property and the li and Na storage capacity of graphene nanomaterials: A first-principles study

We performed first-principles calculations to investigate the effect of N-doping on the electronic structure property and the Li/Na storage behaviors of graphene nanomaterials. Our calculations first revealed that the N-doping treatment can effectively increase the number of C vacancy defects in graphene and the adsorption energy of a Li/Na atom on C vacancy can be largely enhanced by increasing the pyridinic-/pyrrolic-N atoms at the vacancy site. However, the reversible Li/Na capacity of the C vacancy defect was found to be largely reduced by increasing the doping level of N, which was primarily determined by the electronic structure property of the N-doped graphene structures and their strong electrostatic interactions with Li/Na. Our results clearly revealed that the enhanced Li/Na capacity by the N-doping on the graphene surface can be primarily attributed to the induced formation of a great number of C vacancy defects rather than the presence of the pyridinic-/pyrrolic-N on the basal plane. Our calculations also showed that the pyridinic-N doped graphene edges can possess a Li/Na capacity comparable to that of the N-doped C vacancy defects. Nevertheless, this excess Li/Na capacity was found to be largely reduced by the termination of the H atoms on these edge pyridinic-N groups.