Graphene oxide, highly reduced graphene oxide, and graphene: versatile building blocks for carbon-based materials

Tuning the Hydrophobicity of Laser-Annealed rGO Thin Films Synthesized by Pulsed Laser Deposition

Reduced graphene oxide (rGO) has captivated the scientific community due to its exceptional electrical conductivity, high specific surface area, and excellent mechanical strength. The physical properties of reduced graphene oxide (rGO) are strongly dependent on the presence of different functional groups in its structural framework, along with surface roughness. In this study, laser annealing was employed by a nanosecond Nd:YAG laser to investigate the impact of varying laser energies on the wettability and conductivity of reduced graphene oxide (rGO) samples grown by the pulsed laser deposition (PLD) technique. The rGO films were annealed with different laser fluences, such as 10, 20, 30, 38, 48, 55, and 250 mJ/cm2. Our results reveal a notable transition in wettability, transforming the initially hydrophobic rGO samples into a hydrophilic state. Hydrophilic graphene oxide (GO) or reduced graphene oxide (rGO) surfaces have significant potential for use in biomedical applications due to their unique combination of properties, including biocompatibility, high surface area, and abundant oxygen-containing functional groups. Along with wettability properties, conductivity changes were also observed. The presented findings not only contribute to the understanding of laser-induced modifications in rGO but also highlight the potential applications of controlled laser annealing in tailoring the surface properties of graphene-based materials for diverse technological advancements.

Enhanced Stretchable 2D Metal-Graphene Membranes with Superior Mechanical Properties for Sieving Lithium from Brine

Designing mechanically robust, 2D membranes with elastic properties is crucial for advancing separation technologies, particularly in demanding environments such as saline lakes. Here, an innovative approach, the synthesis of silver nanosheets within graphene oxide (GO) membranes to form a 2D silver-graphene heterojunction, is introduced. This membrane exhibits exceptional mechanical strength (stress tolerance of 4.26 MPa and strain capacity of 123.03%), attributed to the reinforcing effect and ductility of silver nanosheets interacting synergistically with GO layers. Notably, the membrane demonstrates high selectivity for lithium ions in Salt Lake brine (Li⁺/Mg2⁺ ≈ 29.0, Na⁺/Mg2⁺ ≈ 183.3). Through dynamic stretching, the membrane enables precise modulation of ion permeability and selectivity, highlighting its versatility and practicality in complex separation processes. This study marks a significant advancement in membrane design, underscoring its potential in addressing challenges posed by diverse industrial applications, particularly in saline environments.

A Comprehensive Review on Bioprinted Graphene-Based Material (GBM)-Enhanced Scaffolds for Nerve Guidance Conduits

Peripheral nerve injuries (PNIs) pose significant challenges to recovery, often resulting in impaired function and quality of life. To address these challenges, nerve guidance conduits (NGCs) are being developed as effective strategies to promote nerve regeneration by providing a supportive framework that guides axonal growth and facilitates reconnection of severed nerves. Among the materials being explored, graphene-based materials (GBMs) have emerged as promising candidates due to their unique properties. Their unique properties-such as high mechanical strength, excellent electrical conductivity, and favorable biocompatibility-make them ideal for applications in nerve repair. The integration of 3D printing technologies further enhances the development of GBM-based NGCs, enabling the creation of scaffolds with complex architectures and precise topographical cues that closely mimic the natural neural environment. This customization significantly increases the potential for successful nerve repair. This review offers a comprehensive overview of properties of GBMs, the principles of 3D printing, and key design strategies for 3D-printed NGCs. Additionally, it discusses future perspectives and research directions that could advance the application of 3D-printed GBMs in nerve regeneration therapies.

Performance Assessment of Graphene Oxide as a Protective Coating for Historical Stone

Stone cultural heritage faces significant deterioration from environmental factors, necessitating protective treatments that preserve both functionality and appearance. In this study, graphene oxide (GO) was evaluated as a protective coating for both natural and artificially aged Euganean trachyte and Vicenza stone samples. GO was applied as a low-concentration aqueous dispersion (0.5 mg/mL) by brush, and samples were subsequently exposed to UV light for 7 h to simulate weathering. Performance was assessed in accordance with European standards through measurements of water capillary absorption, water vapor permeability, contact angle, and color variation; further characterization was conducted using FT-IR, Raman spectroscopy, SEM, and XRD. Results indicate that GO coatings reduce the water capillary absorption coefficient by up to 49% for Euganean trachyte and 22% for Vicenza stone, while maintaining vapor permeability close to that of untreated samples. Although UV exposure permanently darkens the coating, it slightly enhances hydrophobicity, likely due to differential photoreduction of thin surface layers versus thicker pore-associated GO domains. These findings suggest that, while GO, particularly after UV weathering, shows promise for stone protection, further research is crucial to optimize coating uniformity and assess long-term durability under realistic environmental conditions.

Covalent Functionalisation of rGO and Nanodiamonds: Complementary Versatility and Applicability of Azomethine Ylide, Nitrile Oxide and Nitrone

The existing synthetic protocols for the direct functionalization of carbon-based nanomaterials often entail limitations due to their harsh reaction conditions, which require the use of high temperatures for extended periods. This study aims to overcome these limitations by developing mild and efficient synthetic protocols around 1,3-dipolar cycloaddition. Beginning with the well-established azomethine ylide derivatization, we progress to the utilization of nitrile oxide, and of nitrone derivatives for the functionalization of reduced graphene oxide (rGO) as well as of nanodiamonds (NDs). This comparative work employs both classical heating and microwave activation with the aim of reducing reaction times and enhancing efficacy. Results demonstrate that nitrone can react at 60 °C and that the reaction temperature may be decreased to 30 °C with nitrile oxide. Excellent progress was made in reducing the large excess of dipoles typically required for derivatization. Nitrile oxide was proved to be the most efficient in terms of derivatization degree, while nitrone was the most versatile reagent, facilitating the decoration of the carbon nanolayer with disubstituted dihydroisoxazole. To accurately assess the degree of functionalization, the reaction products underwent characterization using various spectroscopic and analytical techniques. Additionally, an indirect evaluation of the reaction outcome was conducted through Fmoc deprotection and quantification.

Layer-by-Layer Assembly of Graphene Oxide and Silver Nanowire Thin Films with Interdigitated Nanostructure in Dendrite Suppressions of Li-Metal Batteries

Reducing the thickness of the Li-metal anode is key to enhancing the energy density of batteries. However, poor initial lithium deposition on Cu current collectors can exacerbate the growth of lithium dendrites and limit performance. This study explores innovative strategies by fabricating graphene oxide (GO) and silver nanowire (AgNW) thin films onto Cu-foil using the layer-by-layer (LbL) assembly method. The homogeneous LbL thin films are prepared with the assistance of bifunctional cross-linkers, such as cysteamine, to strengthen the intermolecular interactions between the nano-building blocks. The GO/AgNW LbL thin films possess a highly interdigitated nanostructure that combines the synergistic advantages of the individual building components. The GO layers facilitate the distribution of Li-ionic flux through the films, which promotes the formation of stable solid electrolyte interphase layers. In addition, the AgNW layers provide electrical pathways and serve as nucleation sites for Li─Ag alloy reactions. These combined effects lead to a flat and stable initial Li-deposition, as well as dense and compact Li growth, without significant dendrite formation. The full cell tests show excellent cycle longevity, 430 cycles with an N/P ratio of 3.36 at 1 C and 250 cycles with an N/P ratio of 1.81 at 3 C.

Mechanical properties of two-dimensional material-based thin films: a comprehensive review

Two-dimensional (2D) materials are materials with a thickness of one or a few atoms with intriguing electrical, chemical, optical, electrochemical, and mechanical properties. Therefore, they are deemed candidates for ubiquitous engineering applications. Films and three-dimensional (3D) structures made from 2D materials introduce a distinct assembly structure that imparts the inherent properties of pristine 2D materials on a macroscopic scale. Acquiring the adequate strength and toughness of 2D material structures is of great interest due to their high demand for numerous industrial applications. This work presents a comprehensive review of the mechanical properties and deformation behavior of robust films composed of 2D materials that help them to attain other extraordinary properties. Moreover, the various key factors affecting the mechanical performance of such thin films, such as the lateral size of nanoflakes, fabrication technique of the film, thickness of the film, post-processing, and strain rate, are elucidated.

Insights into the Hydration Layer of Reduced Graphene Oxides: A Computational Study

Reduced graphene oxide (rGO) has emerged as a versatile material with diverse applications, particularly in aqueous environments. Understanding its interactions with water molecules is crucial for various fields, ranging from energy storage to sensing. In this study, we investigate the behavior of graphene and rGO in water, focusing on elucidating their wetting properties and the influence of oxygen-containing functional groups. Through extensive molecular dynamics simulations, we analyze the orientation and electrostatic dipole of water molecules near the rGO interface, revealing a direct correlation between rGO hydrophilicity and oxidation level. Specifically, we observe stronger hydrogen bonding networks near higher coverage rGO monolayers, indicating enhanced hydrophilicity. Furthermore, by studying water confined between rGO layers, we find uniform water transport with lateral self-diffusion coefficients comparable to bulk water, highlighting the potential of rGO membranes in various applications. Our findings provide insights into the atomic-scale interactions governing rGO-water interfaces, paving the way for the rational design of graphene-based materials for application in aqueous environments.

Humidity-Sensing Performance of TiO2/RGO and α-Fe2O3/RGO Composites

This study investigates the humidity-sensing properties of two semiconductor metal oxide (SMO)-reduced graphene oxide (RGO) nanocomposites: TiO2/RGO and α-Fe2O3/RGO, at room temperature. Both nanocomposites are synthesized via hydrothermal methods and coated onto printed circuit board (PCB) interdigital electrodes to construct humidity sensors. The surface morphology and crystallographic structure of the materials are characterized using field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). The sensors are tested across a humidity range of 11%RH to 97%RH, and the impedance is measured over a frequency range of 1 Hz to 1 MHz. The results show that both TiO2/RGO and α-Fe2O3/RGO exhibit favorable humidity-sensing performance at room temperature. The sensitivity and humidity hysteresis of TiO2/RGO are 12.2 MΩ/%RH and 3.811%RH, respectively, while those of α-Fe2O3/RGO are 0.826 MΩ/%RH and 8.229%RH. The response and recovery times of TiO2/RGO are 72 s and 99 s, respectively, while those of α-Fe2O3/RGO are 48 s and 54 s. Both sensors demonstrate good repeatability and stability. These findings suggest that SMO/RGO nanocomposites are promising materials for the development of low-cost, high-sensitivity, and stable humidity sensors.

Effect of Doping Cement Mortar with Triclosan, Hypochlorous Acid, Silver Nanoparticles and Graphene Oxide on Its Mechanical and Biological Properties

In order to improve the performance of cement mortar (Portland cement), it was enriched with triclosan, hypochlorous acid, silver nanoparticles and graphene oxide. Cement mortar is used, among other things, to fill the gaps between the tiles of building porcelain stoneware. A number of structural, mechanical and biological tests were carried out. The structural tests included microscopic analysis and contact angle, reflectance and IR spectra, while the mechanical tests involved static bending and compression testing. These tests showed that the additions of graphene oxide and hypochlorous acid were most beneficial. These additions, although not detected by spectral methods, resulted in a significant increase in contact angle and mechanical properties. Studies of the viability of the bacteria Pseudomonas aeruginosa and Staphylococcus aureus showed that all the additives used resulted in a decrease in viability compared to the undoped cement mortar. There was also a beneficial decrease in the viability of fungi of the genus Fusarium on cement mortar mainly doped with silver nanoparticles.

Fabrication of high-resolution, flexible, laser-induced graphene sensors via stencil masking

The advent of wearable sensing platforms capable of continuously monitoring physiological parameters indicative of health status have resulted in a paradigm shift for clinical medicine. The accessibility and adaptability of such portable, unobtrusive devices enables proactive, personalized care based on real-time physiological insights. While wearable sensing platforms exhibit powerful capabilities for continuously monitoring physiological parameters, device fabrication often requires specialized facilities and technical expertise, restricting deployment opportunities and innovation potential. The recent emergence of rapid prototyping approaches to sensor fabrication, such as laser-induced graphene (LIG), provides a pathway for circumventing these barriers through low-cost, scalable fabrication. However, inherent limitations in laser processing restrict the spatial resolution of LIG-based flexible electronic devices to the minimum laser spot size. For a CO2 laser-a commonly reported laser for device production-this corresponds to a feature size of ∼120 μm. Here, we demonstrate a facile, low-cost stencil-masking technique to reduce the minimum resolvable feature size of a LIG-based device from 120 ± 20 μm to 45 ± 3 μm when fabricated by CO2 laser. Characterization of device performance reveals this stencil-masked LIG (s-LIG) method yields a concomitant improvement in electrical properties, which we hypothesize is the result of changes in macrostructure of the patterned LIG. We showcase the performance of this fabrication method via production of common sensors including temperature and multi-electrode electrochemical sensors. We fabricate fine-line microarray electrodes not typically achievable via native CO2 laser processing, demonstrating the potential of the expanded design capabilities. Comparing microarray sensors made with and without the stencil to traditional macro LIG electrodes reveals the s-LIG sensors have significantly reduced capacitance for similar electroactive surface areas. Beyond improving sensor performance, the increased resolution enabled by this metal stencil technique expands capabilities for scalable fabrication of high-performance wearable sensors in low-resource settings without reliance on traditional fabrication pathways.

Atomistic insights into the nucleation and growth of hexagonal boron nitride and graphene heterostructures

Graphene and hexagonal boron nitride (hBN) are two-dimensional (2D) materials with a similar atomic structure but drastically different although complementary electronic properties. The large-scale synthesis of h-BN/graphene heterostructures with high crystallographic quality is required to fully benefit of the graphene electronic properties. In this study, we examine numerically the interaction of graphene precursors on hBN and of hBN precursors on graphene to gain deep insight of the CVD and MBE growth mechanism of graphene/hBN heterostructures. Density functional theory (DFT) calculations reveal the adsorption and diffusion behaviors for B, N, and C atoms on these surfaces. In particular, the adsorption energy is found to be similar to the diffusion barriers, except for the nearly free diffusion of B atoms on both graphene and hBN. We have also investigated the transition from individual atoms to graphene or h-BN seeds by considering the stability of linear chains as well as branched and ring seeds. Furthermore, for larger clusters, the triangular h-BN domains are found to be equally thermodynamically stable on graphene regardless of their orientation. These findings provide preliminary hints for the ability of graphene to grow on hBN layers and hBN layer on graphene.

Graphene-Based Wound Dressings for Wound Healing: Mechanism, Technical Analysis, and Application Status

The development of novel wound dressings is critical in medical care. Graphene and its derivatives possess excellent biomedical properties, making them highly suitable for various applications in medical dressings. This review provides a comprehensive technical analysis and the current application status of graphene-based medical dressings. Initially, we discuss the chemical structure and the fabrication method of graphene and its derivatives. We then provide a detailed summary of the mechanisms by which graphene materials promote wound repair across the four stages of wound healing. Subsequently, we categorize the types of graphene-based wound dressings and analyze corresponding characteristics. Finally, we analyze the challenges encountered at present and propose solutions regarding future development trends. This paper aims to serve as a reference for further research in skin tissue engineering and the development of innovative graphene-based medical dressings.

Effect of Addition Amount of Ethylenediamine on Interlayer Nanochannels and the Separation Performance of Graphene Oxide Membranes

In recent years, graphene oxide (GO)-based two-dimensional (2D) laminar membranes have attracted considerable attention because of their unique well-defined nanochannels and deliver a wide range of molecular separation properties and fundamentals. However, the practical application of 2D GO layered membranes suffers from instability in aqueous solutions as the interlayer d-spacing of GO membranes is prone to expansion caused by the hydration effect. In this study, the effects of the ethylenediamine (EDA) addition amount on the structure, crosslinking mechanism and separation performance of GO membranes were investigated systematically, and membrane performance was evaluated using water permeability and dye/salt rejection tests. The experimental results show that the amine groups of EDA chemically bond with the hydroxyl functional group (O=C-OH) of GO after intercalation, as evident from Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). By further controlling the amount of the intercalated EDA, the as-prepared GO composite membranes show nanoscale-tuned d-spacing promising for downstream applications. In the demonstrated dye/salt nanofiltration scenario, the EDA intercalated and crosslinked GO membrane has enhanced permeability by over five times and a better dye rejection rate of over 96% compared with pure GO membranes. These findings highlight a facile strategy for controlling nanochannels by tuning the amounts of reactive intercalants.

Graphene-Based Catalysts: Emerging Applications and Potential Impact

Carbon nanofillers in general and graphene in particular are considered as promising potential candidates in catalysis due to their two-dimensional (2D) nature, zero bandwidth, single atom thickness with a promising high surface area: volume ratio. Additionally, graphene oxide via result of tunable electrical properties has also been developed as a catalytic support for metal and metal oxide nanofillers. Moreover, the possession of higher chemical stability followed by ultrahigh thermal conductivity plays a prominent role in promoting higher reinforcement of catalytically active sites. In this review we have started with an overview of carbon nanofillers as catalyst support, their main characteristics and applications for their use in heterogeneous catalysis. The review article also critically focusses on the catalytic properties originating from both functional groups as well as doping. An in-depth literature on the various reaction catalysed by metal oxide based nanoparticles supported on GO/rGO has also been incorporated with a special focus on the overall catalytic efficiency with respect to graphene contribution. The future research prospective in the aforementioned field has also been discussed.

Hydrogen bonding-regulated miscibility of graphene oxide and nonionic water-soluble polymers

The integration of graphene and nonionic water-soluble polymers has generated useful composites with high performances and rich functionalities. These attractive graphene composites are usually synthesized from the aqueous mixture of graphene oxide (GO) precursor and polymers such as synthetic polyvinyl alcohol and natural cellulose. In this widely known preparation method, the miscibility of GO and nonionic water-soluble polymers seems to be intuitive but has been disputed by some observations of gelation and aggregation. Herein, we have re-examined the miscibility of GO and nonionic water-soluble polymers and confirm their general coaggregation caused by hydrogen bonding interaction. Due to the increasing GO concentration, the property of stable miscibility is converted to aggregation by surface adsorption with transient hydrogen bond crosslinking. We have proposed a preheat mixing strategy to prepare a homogenous solution of GO and nonionic water-soluble polymers in any arbitrary ratio. The re-exploited miscibility allows the fabrication of homogeneous composite papers with renewed high performance trend. The hydrogen bonding-regulated miscibility refreshes the understanding on graphene/water-soluble polymeric composites and provides an ecofriendly interaction control method to modulate the assembly of structures and materials.

Revisiting oxidation and reduction reactions for synthesizing a three-dimensional hydrogel of reduced graphene oxide

An improvement to Hummers' method involving a cascade-design graphite oxidation reaction is reported to optimize safety and efficiency in the production of graphite oxide (GrO) and graphene oxide (GO). Chemical reduction using highly alkaline ammonia solution is a novel approach to synthesizing reduced graphene oxide (RGO). In this original research, we revisit the oxidation and reduction reactions, providing significant findings regarding the synthetic pathway to obtain a bioinspired water-intercalated hydrogel of RGO nanosheets. Influential factors in the graphite oxidation reaction, typically the exothermic reaction temperature and hydrogen peroxide effect, are described. Furthermore, the chemical reaction of GO reduction using highly alkaline ammonia solution (pH 14) was investigated to produce hydrated RGO nanosheets assembled in a hydrogel structure (97% water). Three-dimensional assembly and water intercalation are key to preserve the non-stacking state of RGO nanosheets. Therefore, ultrasound transmission to aqueous channels in the macroscopic RGO hydrogel vibrated and dispersed the RGO nanosheets in water. Analytical results revealed the single-layer nanostructures, functional groups, optical band gaps, optimized C/O ratios, particle sizes and zeta potentials of GO and RGO nanosheets. The reversible self-assembly of RGO hydrogels is essential for many applications, such as RGO coatings and polymer/RGO nanocomposites. In a water purification application, the RGO hydrogel was dispersed in aqueous solution by simple agitation and showed a high capacity for organic dye adsorption. After the adsorption, the RGO/dye particles were easily removed by filtration through ordinary cellulose paper. The process of adsorption and filtration is effective and inexpensive for practical environmental remediation. In summary, a bioinspired structure of RGO hydrogel is conceptualized for prospective nanotechnology.

NaOH-assisted hydrothermal reduction of graphene oxide

The influence of the pH of the reaction medium on the structural characteristics of hydrothermally reduced graphene oxide, synthesized by the tour method, has been investigated. Varying the pH of the reaction medium within the range of 8.0, 10.0 and 12.0 (adjusted with NaOH) has revealed distinct effects on the morphology and properties of the resulting reduced graphene oxide. At a pH of 8.0 the hydrothermal treatment yielded reduced graphene oxide comprising of two particle fractions with a thickness equivalent to 4-5 graphitic layers each. In contrast, pH of 10.0 resulted in two particle fractions corresponding to 2-3 and 4 layers, respectively, while pH of 12.0 produced a single fraction with a particle thickness of 0.70 nm, encompassing 3 graphitic layers. Increasing the pH led to a decrease in the average lateral size of reduced graphene oxide particles to about 8 nm. All rGOs had micro- and mesopores with a specific surface area up to 226 m2g-1, showing a proportional increase in mesopores with increasing pH. Analysis of slit-like micropores revealed a minimum fractal dimension (D= 2.18) at pH = 8.0. The obtained results provide valuable insights into tailoring the structural properties of hydrothermally reduced graphene oxide by controlling the pH of the reaction medium, offering potential applications in various fields, including nanotechnology and materials science.

Innovative voltammetric techniques for bumadizone analysis in pharmaceutical and biological samples: emphasizing green, white, and blue analytical approaches

There are no documented electroanalytical methods for quantifying the anti-inflammatory drug bumadizone (BUM) in pharmaceutical or biological matrices. So, a new voltammetric method was developed to determine BUM at nano concentrations in pharmaceutical forms, in the presence of its alkaline degradant, and in biological fluids. Five electrodes were tested, including three nano-reduced graphene oxide (nRGO) electrodes (5%, 15%, and 20%), a carbon paste electrode (CPE), and a 10% nRGO-modified CPE. The 10% nRGO-modified electrode showed the best performance, offering high selectivity and low detection limits, with good linearity in the concentration range of 0.9 × 102 to 15 × 102 ng mL-1. Differential pulse voltammetry successfully applied this electrode for BUM determination in various samples, achieving excellent recovery without preliminary separation. The method was validated according to ICH guidelines and compared favorably to the reference method. Its environmental impact was assessed using AGREE and Eco-scale metrics in addition to the RGB algorithm, showing superior greenness and whiteness profiles due to safer solvents and lower energy consumption, along with high practical effectiveness using the BAGI metric.

Chemiresistive Gas Sensing using Graphene-Metal Oxide Hybrids

Chemiresistive sensing lies in its ability to provide fast, accurate, and reliable detection of various gases in a cost-effective and non-invasive manner. In this context, graphene-functionalized metal oxides play crucial role in hydrogen gas sensing. However, a cost-effective, defect-free, and large production schemes of graphene-based sensors are required for industrial applications. This review focuses on graphene-functionalized metal oxide nanostructures designed for gaseous molecules detection, mainly hydrogen gas sensing applications. For the convenience of the reader and to understand the role of graphene-metal oxide hybrids (GMOH) in gas sensing activities, a brief overview of the properties and synthesis routes of graphene and GMOH have been reported in this paper. Metal oxides play an essential role in the GMOH construct for hydrogen gas sensing. Therefore, various metal oxides-decorated GMOH constructs are detailed in this review as gas sensing platforms, particularly for hydrogen detection. Finally, specific directions for future research works and challenges ahead in designing highly selective and sensitive hydrogen gas sensors have been highlighted. As illustrated in this review, understanding of the metal oxides-decorated GMOH constructs is expected to guide ones in developing emerging hybrid nanomaterials that are suitable for hydrogen gas sensing applications.

Modulation of Interlayer Nanochannels via the Moderate Heat Treatment of Graphene Oxide Membranes

In response to the phenomenon of interlayer transport channel swelling caused by the hydration of oxygen-containing functional groups on the GO membrane surface, a moderate heat treatment method was employed to controllably reduce the graphene oxide (GO) membrane and prepare a reduced GO composite nanofiltration membrane (mixed cellulose membrane (MCE)/ethylenediamine (EDA)/reduced GO-X (RGO-X)). The associations of different heat treatment temperatures with the hydrophilicity, interlayer structure, permeability and dye/salt rejection properties of GO membranes were systematically explored. The results indicated that the oxygen-containing groups of the GO membrane were partially eliminated after heat treatment, and the hydrophilicity was weakened. This effectively weakened the hydration between the GO membrane and the water molecules and inhibited the swelling of the oxidized graphene membrane. In the dye desalination test, the MCE/EDA/RGO membrane exhibited an ultra-high rejection rate of over 97% for methylene blue (MB) dye molecules. In addition, heat treatment increased the structural defects of the GO membrane and promoted the fast passage of water molecules via the membrane. In pure water flux testing, the water flux of the membrane remained above 46.58 Lm-2h-1bar-1, while the salt rejection rate was relatively low.

A g-C3N4/rGO/Cs3Bi2Br9 mediated Z-scheme heterojunction for enhanced photocatalytic CO2 reduction

Photocatalytic CO2 reduction plays a crucial role in advancing solar fuels, and enhancing the efficiency of the chosen photocatalysts is essential for sustainable energy production. This study demonstrates advancements in the performance of g-C3N4 as a photocatalyst achieved through surface modifications such as exfoliation to increase surface area and surface oxidation for improved charge separation. We also introduce reduced graphene oxide (rGO) in various ratios to both bulk and exfoliated g-C3N4, which effectively mitigates charge recombination and establishes an optimal ratio for enhanced efficiency. g-C3N4/rGO serves to fabricate a hybrid organic/inorganic heterojunction with Cs3Bi2Br9, resulting in a g-C3N4/rGO/Cs3Bi2Br9 composite. This leads to a remarkable increase in photocatalytic conversion of CO2 and H2O to CO, H2 and CH4 at rates of 54.3 (±2.0) μmole- g-1 h-1, surpassing that of pure Cs3Bi2Br9 (11.2 ± 0.4 μmole- g-1 h-1) and bulk g-C3N4 (5.5 ± 0.5 μmole- g-1 h-1). The experimentally determined energy diagram indicates that rGO acts as a solid redox mediator between g-C3N4 and Cs3Bi2Br9 in a Z-scheme heterojunction configuration, ensuring that the semiconductor (Cs3Bi2Br9) with the shallowest conduction band drives the reduction and the one with the deepest valence band (g-C3N4) drives the oxidation. The successful formation of this high-performance heterojunction underscores the potential of the developed composite as a photocatalyst for CO2 reduction, offering promising prospects for advancing the field of solar fuels and achieving sustainable energy goals.

Carbon Fiber-Based Vitrimer Composites: A Path toward Current Research That Is High-Performing, Useful, and Sustainable

In the polymeric material industry, thermosets and related composites have played a substantial role in the production of rubber and plastics. One important subset of these is thermoset composites with carbon reinforcement. The incorporation of carbon fillers and fibers gives polymeric materials improved electrical and mechanical properties, among other benefits. However, the covalently crosslinked network of thermosets presents significant challenges for recycling and reprocessing because of its intractable nature. The introduction of vitrimer materials opens a new avenue to produce biodegradable and recyclable thermosets. Carbon-reinforced vitrimer composites are pursued for high-performance, long-lasting materials with attractive physical properties, the ability to be recycled and processed, and other features that respond uniquely to stimuli. The development of carbon-reinforced vitrimer composites over the last few years is summarized in this article. First, an overview of vitrimers and the methods used to prepare carbon fiber-reinforced vitrimer composites is provided. Because of the vitrimer nature of such composites, reprocessing, healing, and recycling are viable ways to greatly extend their service life; these approaches are thoroughly explained and summarized. The conclusion is our prediction for developing carbon-based vitrimer composites.

Investigating Permselectivity in PVDF Mixed Matrix Membranes Using Experimental Optimization, Machine Learning Segmentation, and Statistical Forecasting

This research examines the correlation between interfacial characteristics and membrane distillation (MD) performance of copper oxide (Cu) nanoparticle-decorated electrospun carbon nanofibers (CNFs) polyvinylidene fluoride (PVDF) mixed matrix membranes. The membranes were fabricated by a bottom-up phase inversion method to incorporate a range of concentrations of CNF and Cu + CNF particles in the polymer matrix to tune the porosity, crystallinity, and wettability of the membranes. The resultant membranes were tested for their application in desalination by comparing the water vapor transport and salt rejection rates in the presence of Cu and CNF. Our results demonstrated a 64% increase in water vapor flux and a salt rejection rate of over 99.8% with just 1 wt % loading of Cu + CNF in the PVDF matrix. This was attributed to enhanced chemical heterogeneity, porosity, hydrophobicity, and crystallinity that was confirmed by electron microscopy, tensiometry, and scattering techniques. A machine learning segmentation model was trained on electron microscopy images to obtain the spatial distribution of pores in the membrane. An Autoregressive Integrated Moving Average with Explanatory Variable (ARIMAX) statistical time series model was trained on MD experimental data obtained for various membranes to forecast the membrane performance over an extended duration.

Bioelectronic Neural Interfaces: Improving Neuromodulation Through Organic Conductive Coatings

Integration of bioelectronic devices in clinical practice is expanding rapidly, focusing on conditions ranging from sensory to neurological and mental health disorders. While platinum (Pt) electrodes in neuromodulation devices such as cochlear implants and deep brain stimulators have shown promising results, challenges still affect their long-term performance. Key among these are electrode and device longevity in vivo, and formation of encapsulating fibrous tissue. To overcome these challenges, organic conductors with unique chemical and physical properties are being explored. They hold great promise as coatings for neural interfaces, offering more rapid regulatory pathways and clinical implementation than standalone bioelectronics. This study provides a comprehensive review of the potential benefits of organic coatings in neuromodulation electrodes and the challenges that limit their effective integration into existing devices. It discusses issues related to metallic electrode use and introduces physical, electrical, and biological properties of organic coatings applied in neuromodulation. Furthermore, previously reported challenges related to organic coating stability, durability, manufacturing, and biocompatibility are thoroughly reviewed and proposed coating adhesion mechanisms are summarized. Understanding organic coating properties, modifications, and current challenges of organic coatings in clinical and industrial settings is expected to provide valuable insights for their future development and integration into organic bioelectronics.

A Pressure and Proximity Sensor Based on Laser-Induced Graphene

Smart wearable devices are extensively utilized across diverse domains due to their inherent advantages of flexibility, portability, and real-time monitoring. Among these, flexible sensors demonstrate exceptional pliability and malleability, making them a prominent focus in wearable electronics research. However, the implementation of flexible wearable sensors often entails intricate and time-consuming processes, leading to high costs, which hinder the advancement of the entire field. Here, we report a pressure and proximity sensor based on oxidized laser-induced graphene (oxidized LIG) as a dielectric layer sandwiched by patterned LIG electrodes, which is characterized by high speed and cost-effectiveness. It is found that in the low-frequency range of fewer than 0.1 kHz, the relative dielectric constant of the oxidized LIG layer reaches an order of magnitude of 104. The pressure mode of this bimodal capacitive sensor is capable of detecting pressures within the range of 1.34 Pa to 800 Pa, with a response time of several hundred milliseconds. The proximity mode involves the application of stimulation using an acrylic probe, which demonstrates a detection range from 0.05 mm to 37.8 mm. Additionally, it has a rapid response time of approximately 100 ms, ensuring consistent signal variations throughout both the approach and withdrawal phases. The sensor fabrication method proposed in this project effectively minimizes expenses and accelerates the preparation cycle through precise control of laser processing parameters to shape the electrode-dielectric layer-electrode within a single substrate material. Based on their exceptional combined performance, our pressure and proximity sensors exhibit significant potential in practical applications such as motion monitoring and distance detection.

Persulfate assisted photocatalytic and antibacterial activity of TiO2-CuO coupled with graphene oxide and reduced graphene oxide

Photocatalysts of TiO2-CuO coupled with 30% graphene oxide (GO) were hydrothermally fabricated, which varied the TiO2 to CuO weight ratios to 1:4, 1:2, 1:1, 2:1 and 4:1 and reduced to form TiO2-CuO/reduced graphene oxide (rGO) photocatalysts. They were characterized using XRD, TEM, SEM, XPS, Raman, and DRS technologies. TiO2-CuO composites and TiO2-CuO/GO degrade methylene blue when persulfate ions are present. Persulfate concentration ranged from 1, 2, 4 to 8 mmol/dm-3 in which the highest activity of 4.4 × 10-2 and 7.35 × 10-2 min-1 was obtained with 4 mmol/dm-3 for TiO2-CuO (1:4) and TiO2-CuO/GO (1:1), respectively. The presence of EDTA and isopropyl alcohol reduced the photodegradation. TiO2-CuO coupled with rGO coagulates methylene blue in the presence of persulfate ions and such coagulation is independent of light. The catalyst dosage and the concentration of the dye were varied for the best-performing samples. The antibacterial activity of the synthesized samples was evaluated against the growth of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella pneumonia. Ti:Cu (1:2)-GO and Ti:Cu (1:4)-GO had the highest antibacterial activity against K. pneumoniae (16.08 ± 0.14 mm), P. aeruginosa (22.33 ± 0.58 mm), E. coli (16.17 ± 0.29 mm) and S. aureus (16.08 ± 0.88).

Interfacial Growth of Large Area Single-Crystalline Silver Sheets Through Ambient Microdroplets

The creation of micrometer-sized sheets of silver at the air-water interface by direct deposition of electrospray-generated silver ions (Ag+) on an aqueous dispersion of reduced graphene oxide (RGO), in ambient conditions, is reported. In the process of electrospray deposition (ESD), an electrohydrodynamic flow is created in the aqueous dispersion, and the graphene sheets assemble, forming a thin film at the air-water interface. The deposited Ag+ coalesce to make single-crystalline Ag sheets on top of this assembled graphene layer. Fast neutralization of Ag+ forming atomic Ag, combined with their enhanced mobility on graphene surfaces, presumably facilitates the growth of larger Ag clusters. Moreover, restrictions imposed by the interface drive the crystal growth in 2D. By controlling the precursor salt concentration, RGO concentration, deposition time, and ion current, the dimensionality of the Ag sheets can be tuned. These Ag sheets are effective substrates for surface-enhanced Raman spectroscopy (SERS), as demonstrated by the successful detection of methylene blue at nanomolar concentrations.

A novel and efficient voltammetric sensor for the simultaneous determination of alizarin red S and tartrazine by using poly(leucine) functionalized carbon paste electrode

In the current work, a rapid, selective, and sensitive technique was developed for the detection of Alizarin Red S (ARS) by applying poly leucine modified carbon paste electrode (PLMCPE). Electrochemical impedance spectroscopy (EIS) and Scanning electron microscopy (SEM) were utilized to study the surface morphology of unmodified carbon paste electrode (UMCPE) and PLMCPE. The active surface area for UMCPE and PLMCPE was found to be 0.0012 cm2 and 0.0026 cm2 respectively. The electrochemical response of ARS at UMCPE and PLMCPE was analyzed using cyclic voltammetry (CV) in the potential window of 0.4 to 1.0 V. The cyclic voltammogram obtained for varying the pH of 0.2 M phosphate buffer (PB) solution showed maximum current for the oxidation of ARS at pH 6.5. The electrochemical reaction of ARS was found to be irreversible and adsorption controlled. The effect of variation of concentration of ARS on the oxidation peak current was evaluated using CV and linear scan voltammetry (LSV). A linear relationship between the concentration variation and current was obtained in the linear range of 1.5 μM-3.5 μM and 0.2 μM-5.0 μM for CV and LSV respectively. The limit of detection (LOD) of 0.68 μM for the CV method and 0.29 μM for the LSV method was exhibited by the developed sensor. The simultaneous study of ARS along with tartrazine (TZ) showed good selectivity for ARS. The interferents of foreign molecules showed no effect on the selectivity of the electrode. The applicability of PLMCPE on real samples gave good recovery ranging from 97.46-101.2%; hence, the sensor can be utilized on real samples. The developed sensor has good stability and sensitivity.

Applications of graphene oxide and reduced graphene oxide in advanced dental materials and therapies

The graphene family of nanomaterials acquired significant attention in the field of dentistry due to a range of interesting properties. Graphene oxide (GO) and reduced graphene oxide (rGO) are the major graphene derivatives that are widely used in dental applications. These derivatives exhibit excellent mechanical properties, superior biocompatibility, good antibacterial properties, extreme chemical stability, and favorable tribological characteristics, thus representing highly materials for dentistry. The amphiphilic nature of GO allows covalent and noncovalent modifications that are favorable for biomedical applications. Graphene can influence the differentiation of dental pulp stem cells (DPSCs) and enhance the properties of other biomaterials. Here, we review the dental applications of GO or rGO with regards to antimicrobial activity, therapeutic drug delivery, restorative dentistry, implants, pulp regeneration, bone regeneration, periodontal tissue regeneration, biosensors, and tooth whitening.

A novel electrical depercolation model for stretchable nanocomposite strain sensors

Flexible strain sensors have been subject to intense research efforts in recent years, in an attempt to overcome the limitations of their rigid counterparts and find use in demanding applications. In this work, the effective calibration of resistive-type, stretchable strain sensors is discussed. A new model for the piezoresistive response of stretchable polymer nanocomposite strain sensors is presented which facilitates calibration over the full conducting strain range of the material. This offers the potential to vastly improve the practical working range of sensors made using soft conductive nanocomposites, as well as to obtain key information towards improvement of sensing performance. The model has been successfully applied to multiple experimental measurements on silicone rubber (SR) nanocomposites reinforced with reduced graphene oxide (rGO) over a range of filler loadings. The effect of parameters such as filler dimensions, filler orientation and dispersion state is discussed, while predictions on sensitivity and working range are made on the basis of interparticle distance modelling.

Carbon Dots and Their Polymeric Nanocomposites: Insight into Their Synthesis, Photoluminescence Mechanisms, and Recent Trends in Sensing Applications

Carbon dots (CDs), a novel class of carbon-based nanoparticles, have received a lot of interest recently due to their exceptional mechanical, chemical, and fluorescent properties, as well as their excellent photostability and biocompatibility. CDs' emission properties have already found a variety of potential applications, in which bioimaging and sensing are major highlights. It is widely acknowledged that CDs' fluorescence and surface conditions are closely linked. However, due to the structural complexity of CDs, the specific underlying process of their fluorescence is uncertain and yet to be explained. Because of their low toxicity, robust and wide optical absorption, high chemical stability, rapid transfer characteristics, and ease of modification, CDs have been recognized as promising carbon nanomaterials for a variety of sensing applications. Thus, following such outstanding properties of CDs, they have been mixed and imprinted onto different polymeric components to achieve a highly efficient nanocomposite with improved functional groups and properties. Here, in this review, various approaches and techniques for the preparation of polymer/CDs nanocomposites have been elaborated along with the individual characteristics of CDs. CDs/polymer nanocomposites recently have been highly demanded for sensor applications. The insights from this review are detailed sensor applications of polymer/CDs nanocomposites especially for detection of different chemical and biological analytes such as metal ions, small organic molecules, and several contaminants.

Monovalent ion-graphene oxide interactions are controlled by carboxylic acid groups: Sum frequency generation spectroscopy studies

Graphene oxide (GO) is a two-dimensional, mechanically strong, and chemically tunable material for separations. Elucidating GO-ion-water interactions at the molecular scale is highly important for predictive understanding of separation systems. However, direct observations of the nanometer region by GO surfaces under operando conditions are not trivial. Therefore, thin films of GO at the air/water interface can be used as model systems. With this approach, we study the effects of alkali metal ions on water organization near graphene oxide films at the air/water interface using vibrational sum frequency generation (SFG) spectroscopy. We also use an arachidic acid Langmuir monolayer as a benchmark for a pure carboxylic acid surface. Theoretical modeling of the concentration-dependent sum frequency signal from graphene oxide and arachidic acid surfaces reveals that the adsorption of monovalent ions is mainly controlled by the carboxylic acid groups on graphene oxide. An in-depth analysis of sum frequency spectra reveals at least three distinct water populations with different hydrogen bonding strengths. The origin of each population can be identified from concentration dependent variations of their SFG signal. Interestingly, an interfacial water structure seemed mostly insensitive to the character of the alkali cation, in contrast to similar studies conducted at the silica/water interface. However, we observed an ion-specific effect with lithium, whose strong hydration prevented direct interactions with the graphene oxide film.

Highly Aligned Graphene Aerogels for Multifunctional Composites

Stemming from the unique in-plane honeycomb lattice structure and the sp2 hybridized carbon atoms bonded by exceptionally strong carbon-carbon bonds, graphene exhibits remarkable anisotropic electrical, mechanical, and thermal properties. To maximize the utilization of graphene's in-plane properties, pre-constructed and aligned structures, such as oriented aerogels, films, and fibers, have been designed. The unique combination of aligned structure, high surface area, excellent electrical conductivity, mechanical stability, thermal conductivity, and porous nature of highly aligned graphene aerogels allows for tailored and enhanced performance in specific directions, enabling advancements in diverse fields. This review provides a comprehensive overview of recent advances in highly aligned graphene aerogels and their composites. It highlights the fabrication methods of aligned graphene aerogels and the optimization of alignment which can be estimated both qualitatively and quantitatively. The oriented scaffolds endow graphene aerogels and their composites with anisotropic properties, showing enhanced electrical, mechanical, and thermal properties along the alignment at the sacrifice of the perpendicular direction. This review showcases remarkable properties and applications of aligned graphene aerogels and their composites, such as their suitability for electronics, environmental applications, thermal management, and energy storage. Challenges and potential opportunities are proposed to offer new insights into prospects of this material.

Polymer Brushes and Surface Nanostructures: Molecular Design, Precise Synthesis, and Self-Assembly

For over two decades, polymer brushes have found wide applications in industry and scientific research. Now, polymer brush research has been a significant research focus in the community of polymer science. In this review paper, we give an introduction to the synthesis, self-assembly, and applications of one-dimensional (1D) polymer brushes on polymer backbones, two-dimensional (2D) polymer brushes on flat surfaces, and three-dimensional (3D) polymer brushes on spherical particles. Examples of the synthesis of polymer brushes on different substrates are provided. Studies on the formation of the surface nanostructures on solid surfaces are also reviewed in this article. Multicomponent polymer brushes on solid surfaces are able to self-assemble into surface micelles (s-micelles). If the s-micelles are linked to the substrates through cleavable linkages, the s-micelles can be cleaved from the substrates, and the cleaved s-micelles are able to self-assemble into hierarchical structures. The formation of the surface nanostructures by coassembly of polymer brushes and "free" polymer chains (coassembly approach) or polymerization-induced surface self-assembly approach, is discussed. The applications of the polymer brushes in colloid and biomedical science are summarized. Finally, perspectives on the development of polymer brushes are offered in this article.

Cobalt-nickel phosphide supported on reduced graphene oxide for sensitive electrochemical detection of bisphenol A

Bisphenol A (BPA) is a commonly utilized phenolic contaminant in several manufacturing processes, contributing to environmental pollution. Therefore, the detection of BPA holds significant importance for monitoring water quality. In this work, we report a robust electrochemical detection method for BPA utilizing cobalt-nickel bimetal phosphide nanoparticles (CoNiP) supported on reduced graphene oxide (rGO). The CoNiP@rGO-modified glassy carbon electrode exhibits remarkable electrochemical activity in BPA detection. The detection mechanism is controlled by adsorption-mediated electron transfer, showcasing a low limit of detection (LOD) at 0.38 nM and a high sensitivity of 96.4 A M-1 cm-2 within the linear range of 0.001-8 μM. Furthermore, our developed sensor demonstrates good reproducibility and successfully detected BPA in actual water samples. The electrochemical activity of CoNiP@rGO was also characterized for hydroquinone (HQ) detected through a diffusion-controlled mechanism, displaying an excellent sensitivity of 36.4 A M-1 cm-2 across a broad linear range. These findings underscore the promising potential of CoNiP@rGO as a candidate for electrochemical detection of phenolic contaminants, especially in the sensing of BPA in environmental water samples. This efficacy is attributed to the modulation of its electronic properties, combined with its large electroactive surface area and low electron-transfer resistance.

A sustainable bio-based char as emerging electrode material for energy storage applications

In the last few years, extensive research efforts have been made to develop novel bio-char-based electrodes using different strategies starting from a variety of biomass precursors as well as applying different thermochemical conversion paths. In this regard, hydrothermal carbonization method is becoming a more prevalent option among conversion procedures even if pyrolysis remains crucial in converting biomass into carbonaceous materials. The main aim of this study is to develop an innovative supercapacitor electrode from spruce bark waste through a unique low-temperature technique approach, which proved to effectively eliminate the pyrolysis step. Consequently, a hybrid spruce-bark-graphene oxide compound (HySB) was obtained as electrode material for supercapacitors. When compared to a regularly used commercial electrode material, SLC1512P graphite (reference) with 150.3 µF cm-2 capacitance, the HySB has a substantially higher capacitive performance of 530.5 µF cm-2. In contrast to the reference, the HySB polarization resistance increases by two orders of magnitude at the stationary potential and by three orders of magnitude at the optimum potential, underlying that the superior performances of HySB extend beyond static conditions. The synthesis strategy provides an appropriate energy-efficient option for converting biomass into carbonaceous materials with meaningful properties suitable for energy storage applications.

Energy Application of Graphene Based Membrane: Hydrogen Separation

Hydrogen gas (H2 ) is a viable energy carrier that has the potential to replace the traditional fossil fuels and contribute to achieving zero net emissions, making it an attractive option for a hydrogen-based society. However, current H2 purification technologies are often limited by high energy consumption, and as a result, there is a growing demand for alternative techniques that offer higher H2 purity and energy efficiency. Membrane separation has emerged as a promising approach for obtaining high-purity H2 gas with low energy consumption. Nevertheless, despite years of development, commercial polymeric membranes have limited performance, prompting researchers to explore alternative materials. In this context, carbon-based membranes, specifically graphene-based nanomaterials, have gained significant attention as potential membrane materials due to their unique properties. In this review, we provide a comprehensive overview of carbon-based membranes for H2 gas separation, fabrication of the membrane, and its characterization, including their advantages and limitations. We also explore the current technological challenges and suggest insights into future research directions, highlighting potential ways to improve graphene-based membranes performance for H2 separations.

A highly selective and sensitive electrochemical sensor for tetracycline resistant genes detection based on the non-covalent interaction of graphene oxide and nucleobase

Antibiotic resistance genes (ARGs) are causing worldwide environmental problems, however, the traditional analytical methods and test equipment for them are time-consuming and expensive. The electrochemical sensor using the non-covalent bond between graphene oxide (GO) and single-stranded tet (ss-tet) was established for specific tetracycline resistance genes (tet, composed of ss-tet and complementary ss-tet (ss-tet') in water) detection, which preparation time was only 35 min and far less than most reported sensors based on covalent bond. As the result of the detection for tet, the developed sensor not only had the low detection limit of 50.0 pM (8.1 × 102 copies·mL-1), the short detection time within 42 min, but also had satisfactory stability, excellent reproducibility, and highly selectivity (RSD < 4.43 %). Besides, it also had acceptable accuracy comparing to the real-time quantitative polymerase chain reaction (RT-qPCR) and PCR array in tet detection. Noticeably, it also had been successfully applied to tetA detection in different water samples. In brief, the prepared non-covalent bond sensor is simple, rapid, and suitable for highly selective and sensitive detection of the ARGs in actual water.

Graphene-Based Nanomaterials and Their Interactions with Lipid Membranes

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

High-Yield Synthesis of Colloidal Carbon Rings and Their Applications in Self-Standing Electrodes of Li-O2 Batteries

The use of carbon materials in porous electrodes has impressive advantages. However, precisely tailoring the multilevel pore structure of carbon electrodes remains an unsolved challenge. Here, we report a highly efficient site-selective growth strategy to synthesize colloidal carbon rings by templating patchy droplets. Carbon rings are used for the direct fabrication of self-standing porous electrodes with hierarchical pores for lithium-oxygen batteries (LOBs). In situ atomic force microscopy reveals that during discharge the discharge products densely nucleate and grow on carbon rings, demonstrating that such rings are a very potential electrode material in LOBs. The hollow carbon ring electrode (HCRE) possesses micrometer-scale channels formed by random packing of rings and nanochannels consisting of ring-shaped hollow cavities connected by nanosized pores in the wall. Both channels contribute to ion transportation and gas diffusion, but the storage of the discharge products mainly lies in micrometer-scale channels, leading to a high discharge capacity of LOBs (20 658 mAh/g). Our work paves a new way to construct hierarchically porous electrodes for application in electrocatalysis and electrochemical energy storage.

MXene and Xene: promising frontier beyond graphene in tissue engineering and regenerative medicine

The emergence of 2D nanomaterials (2D NMs), which was initiated by the isolation of graphene (G) in 2004, revolutionized various biomedical applications, including bioimaging and -sensing, drug delivery, and tissue engineering, owing to their unique physicochemical and biological properties. Building on the success of G, a novel class of monoelemental 2D NMs, known as Xenes, has recently emerged, offering distinct advantages in the fields of tissue engineering and regenerative medicine. In this review, we focus on the comparison of G and Xene materials for use in fabricating tissue engineering scaffolds. After a brief introduction to the basic physicochemical properties of these materials, recent representative studies are classified in terms of the engineered tissue, i.e., bone, cartilage, neural, muscle, and skin tissues. We analyze several methods of improving the clinical potential of Xene-laden scaffolds using state-of-the-art fabrication technologies and innovative biomaterials. Despite the considerable advantages of Xene materials, critical concerns, such as biocompatibility, biodistribution and regulatory challenges, should be considered. This review and collaborative efforts should advance the field of Xene-based tissue engineering and enable innovative, effective solutions for use in future tissue regeneration.

Ultrasonic neural regulation over two-dimensional graphene analog biomaterials: Enhanced PC12 cell differentiation under diverse ultrasond excitation

Two-dimensional (2D) biomaterials, with unique planar topology and quantum effect, have been widely recognized as a versatile nanoplatform for bioimaging, drug delivery and tissue engineering. However, during the complex application of nerve repair, in which inflammatory microenvironment control is imperative, the gentle manipulation and trigger of 2D biomaterials with inclusion and diversity is still challenging. Herein, inspired by the emerging clinical progress of ultrasound neuromodulation, we systematically studied ultrasound-excited 2D graphene analogues (graphene, graphene oxide, reduced graphene oxide (rGO) and carbon nitride) to explore their feasibility, accessibility, and adjustability for ultrasound-induced nerve repair in vitro. Quantitative observation of cell differentiation morphology demonstrates that PC12 cells added with rGO show the best compatibility and differentiation performance under the general ultrasound mode (0.5 w/cm2, 2 min/day) compared with graphene, graphene oxide and carbon nitride. Furthermore, the general condition can be improved by using a higher intensity of 0.7 w/cm2, but it cannot go up further. Later, ultrasonic frequency and duty cycle conditions were investigated to demonstrate the unique and remarkable inclusion and diversity of ultrasound over conventional electrical and surgical means. The pulse waveform with power of 1 MHz and duty cycle of 50 % may be even better, while the 3 MHz and 100 % duty cycle may not work. Overall, various graphene analog materials can be regarded as biosafe and accessible in both fundamental research and clinical ultrasound therapy, even for radiologists without material backgrounds. The enormous potential of diverse and personalized 2D biomaterials-based therapies can be expected to provide a new mode of ultrasound neuromodulation.

Recent Advances in Biodegradable Green Electronic Materials and Sensor Applications

As environmental issues have become the dominant agenda worldwide, the necessity for more environmentally friendly electronics has recently emerged. Accordingly, biodegradable or nature-derived materials for green electronics have attracted increased interest. Initially, metal-green hybrid electronics are extensively studied. Although these materials are partially biodegradable, they have high utility owing to their metallic components. Subsequently, carbon-framed materials (such as graphite, cylindrical carbon nanomaterials, graphene, graphene oxide, laser-induced graphene) have been investigated. This has led to the adoption of various strategies for carbon-based materials, such as blending them with biodegradable materials. Moreover, various conductive polymers have been developed and researchers have studied their potential use in green electronics. Researchers have attempted to fabricate conductive polymer composites with high biodegradability by shortening the polymer chains. Furthermore, various physical, chemical, and biological sensors that are essential to modern society have been studied using biodegradable compounds. These recent advances in green electronics have paved the way toward their application in real life, providing a brighter future for society.

Multifunctional mesoporous silica nanoparticles for biomedical applications

Mesoporous silica nanoparticles (MSNs) are recognized as a prime example of nanotechnology applied in the biomedical field, due to their easily tunable structure and composition, diverse surface functionalization properties, and excellent biocompatibility. Over the past two decades, researchers have developed a wide variety of MSNs-based nanoplatforms through careful design and controlled preparation techniques, demonstrating their adaptability to various biomedical application scenarios. With the continuous breakthroughs of MSNs in the fields of biosensing, disease diagnosis and treatment, tissue engineering, etc., MSNs are gradually moving from basic research to clinical trials. In this review, we provide a detailed summary of MSNs in the biomedical field, beginning with a comprehensive overview of their development history. We then discuss the types of MSNs-based nanostructured architectures, as well as the classification of MSNs-based nanocomposites according to the elements existed in various inorganic functional components. Subsequently, we summarize the primary purposes of surface-functionalized modifications of MSNs. In the following, we discuss the biomedical applications of MSNs, and highlight the MSNs-based targeted therapeutic modalities currently developed. Given the importance of clinical translation, we also summarize the progress of MSNs in clinical trials. Finally, we take a perspective on the future direction and remaining challenges of MSNs in the biomedical field.

Recent advances in tailoring stimuli-responsive hybrid scaffolds for cardiac tissue engineering and allied applications

To recapitulate bio-physical properties and functional behaviour of native heart tissues, recent tissue engineering-based approaches are focused on developing smart/stimuli-responsive materials for interfacing cardiac cells. Overcoming the drawbacks of the traditionally used biomaterials, these smart materials portray outstanding mechanical and conductive properties while promoting cell-cell interaction and cell-matrix transduction cues in such excitable tissues. To date, a large number of stimuli-responsive materials have been employed for interfacing cardiac tissues alone or in combination with natural/synthetic materials for cardiac tissue engineering. However, their comprehensive classification and a comparative analysis of the role played by these materials in regulating cardiac cell behaviour and in vivo metabolism are much less discussed. In an attempt to cover the recent advances in fabricating stimuli-responsive biomaterials for engineering cardiac tissues, this review details the role of these materials in modulating cardiomyocyte behaviour, functionality and surrounding matrix properties. Furthermore, concerns and challenges regarding the clinical translation of these materials and the possibility of using such materials for the fabrication of bio-actuators and bioelectronic devices are discussed.

Synthesis and evaluation of biological effects of modified graphene oxide nanoparticles containing Lawson (Henna extract) on gastric cancer cells

PURPOSE

Targeted Graphene Oxide (GO) nanoparticles can play an important role in the treatment of cancer by increasing cancer cell targeting. This study was conducted to synthesize GO nanoparticles functionalized with chitosan-folate (CS-FA) to deliver a natural product Lawsone (LA) for cancer treatment.

METHODS

After characterization of the LA-GO-CS-FA, antioxidant activities of the nanoparticles were investigated by ABTS, DPPH, and FRAP tests. CAM assay was used to study the effect of nanoparticles on angiogenesis. The expression level of inflammatory and angiogenic genes in cells treated with nanoparticles was evaluated by real-time PCR.

RESULTS

The findings demonstrated the formation of nanoparticles with a size of 113.3 nm, a PDI of 0.31, and a surface charge of + 11.07 mV. The percentages of encapsulation efficiency were reported at 93%. Gastric cancer cells were reported as the most sensitive to treatment compared to the control, and the gastric cancer cells were used to study gene expression changes. The anti-angiogenic effects of nanoparticles were confirmed by reducing the average number and length of blood vessels and reducing the height and weight of embryos in the CAM assay. The reducing the expression of genes involved in angiogenesis in real-time PCR was demonstrated. Nanoparticles displayed high antioxidant properties by inhibiting DPPH and ABTS radicals and reducing iron ions in the FRAP method. The reduction of pro-inflammatory genes in AGS cells which were treated with nanoparticles indicates the anti-inflammatory properties of nanoparticles.

CONCLUSION

This study showed the efficacy of nanoparticles in inhibiting gastric cancer cells by relying on inhibiting angiogenesis.

Effect of Methyl Groups on Formation of Ordered or Layered Graphitic Materials from Aromatic Molecules

Developing functionally complex carbon materials from small aromatic molecules requires an understanding of how the chemistry and structure of its constituent molecules evolve and crosslink, to achieve a tailorable set of functional properties. Here, molecular dynamics (MD) simulations are used to isolate the effect of methyl groups on condensation reactions during the oxidative process and evaluate the impact on elastic modulus by considering three monodisperse pyrene-based systems with increasing methyl group fraction. A parameter to quantify the reaction progression is designed by computing the number of new covalent bonds formed. Utilizing the previously developed MD framework, it is found that increasing methylation leads to an almost doubling of bond formation, a larger fraction of the new bonds oriented in the direction of tensile stress, and a higher basal plane alignment of the precursor molecules along the direction of tensile stress, resulting in enhanced tensile modulus. Additionally, via experiments, it is demonstrated that precursors with a higher fraction of methyl groups result in a higher alignment of molecules. Moreover, increased methylation results in the lower spread of single molecule alignment which may lead to smaller variations in tensile modulus and more consistent properties in carbon materials derived from methyl-rich precursors.