Graphene Oxide Scaffolds Research Articles

Photothermal effect of graphene oxide accelerate singlet oxygen release from artesunate to endow the scaffold with antibacterial properties

Artesunate, as a semi-synthetic artemisinin derivative, exhibits a broad-spectrum bactericidal effect via the release of singlet oxygen. However, its release is slow due to the difficulty breaking the endoperoxide bridge bond. Ammoniated graphene oxide could be electrostatic adsorbed with artesunate and efficiently transfer thermal energy to artesunate by interfacial heat transfer, thereby facilitating the breaking of the endoperoxide bridge bond. In detail, artesunate was anchored on graphene oxide by a one-pot hydrothermal synthesis method and introduced to the PLLA scaffold fabricated by selective laser sintering. Under near-infrared light irradiation, graphene oxide could convert light to heat through photothermal conversion. Then the heat energy was transferred to artesunate by interfacial heat transfer, accelerating the release of singlet oxygen. Meanwhile, graphene oxide could achieve the purpose of thermal ablation for bacterial infection by increasing the local temperature. Based on the combination of singlet oxygen and thermal ablation therapy, the scaffold possesses a high bactericidal ability triggered by near-infrared light. Under the near-infrared light irradiation, the singlet oxygen production from artesunate increased by 39 %, and the antibacterial ratio against S. aureus and E. coli reached 91.6 % and 93.3 %, respectively. Additionally, the scaffold was favorable cytocompatibility with mBMSCs. All the results highlight the great potential of artesunate-mediated graphene oxide scaffold in eliminating bacterial infections.

Mn and N-doped RGO as a sulfur hosting accelerate electron transfer and redox reactions for Li–S batteries

The notorious polysulfides shuttling and slow redox reaction kinetics largely limit the Li–S battery commercial application as an effective energy storage system. In this report, Mn/N catalysts were co-doped on a high specific surface area reduced graphene oxide (RGO) scaffold by a simple formamide media-assisted method to develop the sulfur holding material for Li–S battery. The N-doped RGO with conductive layer structure not only facilitates the ion and electron transfer, but also provides superb reservoir space for sulfur volume expansion and intermediate polysulfides. Moreover, the introduction of Mn metal catalysts both paly the roles of chemical trappers and electrocatalysts to chemically anchor the polysulfides and accelerate the redox kinetics. It is a promising holding material to improve the reutilization of the polysulfides and suppression of the shuttle effect in lithium-sulfur batteries. As a result, the high initial discharge capacity for the Mn-NG modified Li–S battery is about 1124.7 mAh g−1 at 0.2 C, which can still reach to 914.3 mAh g−1 after 100 cycles, with a retention rate up to 81%. We believe that our method offers a significant approach to prepare multi-functional sulfur hosts for high performance Li–S batteries.

Oriented Graphene Oxide Scaffold Promotes Nerve Regeneration in vitro and in vivo.

Treating peripheral nerve injuries (PNI) with defects remains challenging in clinical practice. The commercial conduits have shown suboptimal nerve regeneration and functional recovery due to their basic tubular design without electroactive and oriented topographical cues. To develop a new scaffold with oriented microstructure and electroactive Graphene oxide (GO) and investigate its' therapeutic effect on nerve regeneration in vitro and in vivo. This study employed a straightforward approach to co-spin PCL and GO, yielding an oriented hybrid nanofibrous scaffold known as the O-GO/PCL scaffold. The physical and chemical properties of nanofibrous scaffold were tested by scanning electron microscopy (SEM), transmission electron microscope (TEM), tensile test and so on. Primary Schwann cells (SCs) and dorsal root ganglia (DRG) were used to investigate the impact of the newly developed scaffolds on the biological behavior of neural cells in vitro. Transcriptome sequencing (mRNA-seq) was employed to probe the underlying mechanisms of the synergistic effect of electroactive GO and longitudinal topographic guidance on nerve regeneration. Furthermore, the developed O-GO/PCL scaffold was utilized to bridge a 10-mm sciatic nerve defect in rat, aiming to investigate its therapeutic potential for peripheral nerve regeneration in vivo. The SEM and TEM revealed that the newly developed O-GO/PCL scaffold showed longitudinally oriented microstructure and GO particles were homogenously and uniformly distributed inside the nanofibers. Primary SCs were utilized to assess the biocompatibility of the GO-based scaffold, revealing that negligible cytotoxicity when GO concentration does not exceed 0.5%. In vitro analysis of nerve regeneration demonstrated that axons in the O-GO/PCL group exhibited an average length of 1054.88 ± 161.32 µm, significant longer than those in the other groups (P < 0.05). Moreover, mRNA sequencing results suggested that the O-GO/PCL scaffold could enhance nerve regeneration by upregulating genes associated with neural regeneration, encompassing ion transport, axon guidance and cell-cell interactions. Most importantly, we employed the O-GO/PCL scaffold to repair a 10-mm sciatic nerve defect in rat, resulting in augmented nerve regeneration, myelination, and functional recovery. The O-GO/PCL scaffold with oriented microstructure and electroactive GO represents a promising heral nerve reconstruction.

3D Graphene/silk fibroin scaffolds enhance dental pulp stem cell osteo/odontogenic differentiation

ObjectivesThe current in vitro study aims to evaluate silk fibroin with and without the addition of graphene as a potential scaffold material for regenerative endodontics. Material and MethodsSilk fibroin (SF), Silk fibroin/graphene oxide (SF/GO) and silk fibroin coated with reduced graphene oxide (SF/rGO) scaffolds were prepared (n = 30). The microarchitectures and mechanical properties of scaffolds were evaluated using field emission scanning electron microscopy (FESEM), pore size and water uptake, attenuated total reflectance fourier transformed infrared spectroscopy (ATR-FTIR), Raman spectroscopy and mechanical compression tests. Next, the study analyzed the influence of these scaffolds on human dental pulp stem cell (hDPSC) viability, apoptosis or necrosis, cell adhesion, odontogenic differentiation marker expression and mineralized matrix deposition. The data were analyzed with ANOVA complemented with the Tukey post-hoc test (p < 0.005). ResultsSEM analysis revealed abundant pores with a size greater than 50 nm on the surface of tested scaffolds, primarily between 50 nm and 600 µm. The average value of water uptake obtained in pure fibroin scaffolds was statistically higher than that of those containing GO or rGO (p < 0.05). ATR-FTIR evidenced that the secondary structures did not present differences between pure fibroin and fibroin coated with graphene oxide, with a similar infrared spectrum in all tested scaffolds. Raman spectroscopy showed a greater number of defects in the links in SF/rGO scaffolds due to the reduction of graphene. In addition, adequate mechanical properties were exhibited by the tested scaffolds. Regarding biological properties, hDPSCs attached to scaffolds were capable of proliferating at a rate similar to the control, without affecting their viability over time. A significant upregulation of ALP, ON and DSPP markers was observed with SF/rGO and SF/GO groups. Finally, SF/GO and SF/rGO promoted a significantly higher mineralization than the control at 21 days. SignificanceData obtained suggested that SF/GO and SF/rGO scaffolds promote hDPSC differentiation at a genetic level, increasing the expression of key osteo/odontogenic markers, and supports the mineralization of the extracellular matrix. However, results from this study are to be interpreted with caution, requiring further in vivo studies to confirm the potential of these scaffolds.

Surface-based modified 3D-printed BG/GO scaffolds promote bone defect repair through bone immunomodulation

Successful bone defect repair requires a favorable immunomodulation. Macrophages are among the frontline cells activated after biomaterial implantation, and biomaterials play a role in the final determination of their fate. The surface properties of biomaterials such as roughness and hydrophilicity can activate macrophages to have an anti-inflammatory phenotype for improving tissue regeneration. Because of its known characteristics, graphene oxide (GO) is widely used in the biomaterials field. GO directly promotes stem cell proliferation and osteogenic differentiation, properties that have been extensively investigated. The aim of this study is to research the effects of the surface-based modified three-dimensional (3D) porous bioactive glass (BG)/GO scaffolds on macrophage activation and bone regeneration. In vivo, compared with the control group receiving BG with a relatively smooth surface, the group receiving the porous implant showed a decreased proinflammatory response in the skin around the implant with increasing GO density, and the 3D porous implant was covered with new bone tissue. In vitro, both Raw264.7 cells and rat bone marrow mesenchymal stem cells (rBMSCs) can adhere and stretch well on rough, hydrophilic BG/GO scaffolds. When Raw264.7 cells were cultured on scaffolds, GO significantly promoted the polarization of M0 macrophages to the M2 type to a certain extent and further promoted the secretion of osteogenic and angiogenic factors, enhancing the osteogenic differentiation of rBMSCs and the angiogenesis of endothelial cells. Further experiments showed that the rough hydrophilic surface of BG/GO might lead to the upregulation of the surface-dependent WNT-3A protein induced by the enhancement of integrin signalling and the accumulation and activation of β-catenin protein in cells. However, excessive content of GO has the opposite regulatory result. These results demonstrate that BG/GO biomaterials with surface-based modification play an important role in bone repair by adjusting the response of macrophages to biomaterials through their surface properties.

3D Graphene Oxide-Polyethylenimine Scaffolds for Cardiac Tissue Engineering.

The development of novel three-dimensional (3D) nanomaterials combining high biocompatibility, precise mechanical characteristics, electrical conductivity, and controlled pore size to enable cell and nutrient permeation is highly sought after for cardiac tissue engineering applications including repair of damaged heart tissues following myocardial infarction and heart failure. Such unique characteristics can collectively be found in hybrid, highly porous tridimensional scaffolds based on chemically functionalized graphene oxide (GO). By exploiting the rich reactivity of the GO's basal epoxydic and edge carboxylate moieties when interacting, respectively, with NH2 and NH3+ groups of linear polyethylenimines (PEIs), 3D architectures with variable thickness and porosity can be manufactured, making use of the layer-by-layer technique through the subsequent dipping in GO and PEI aqueous solutions, thereby attaining enhanced compositional and structural control. The elasticity modulus of the hybrid material is found to depend on scaffold's thickness, with the lowest value of 13 GPa obtained in samples containing the highest number of alternating layers. Thanks to the amino-rich composition of the hybrid and the established biocompatibility of GO, the scaffolds do not exhibit cytotoxicity; they promote cardiac muscle HL-1 cell adhesion and growth without interfering with the cell morphology and increasing cardiac markers such as Connexin-43 and Nkx 2.5. Our novel strategy for scaffold preparation thus overcomes the drawbacks associated with the limited processability of pristine graphene and low GO conductivity, and it enables the production of biocompatible 3D GO scaffolds covalently functionalized with amino-based spacers, which is advantageous for cardiac tissue engineering applications. In particular, they displayed a significant increase in the number of gap junctions compared to HL-1 cultured on CTRL substrates, which render them key components for repairing damaged heart tissues as well as being used for 3D in vitro cardiac modeling investigations.

3D printing of PLA:CaP:GO scaffolds for bone tissue applications.

Graphene oxide (GO) has attracted increasing interest for biomedical applications owing to its outstanding properties such as high specific surface area, ability to bind functional molecules for therapeutic purposes and solubility, together with mechanical resistance and good thermal conductivity. The combination of GO with other biomaterials, such as calcium phosphate (CaP) and biodegradable polymers, presents a promising strategy for bone tissue engineering. Presently, the development of these advanced biomaterials benefits from the use of additive manufacturing techniques, such as 3D printing. In this study, we develop a 3D printed PLA:CaP:GO scaffold for bone tissue engineering. First, GO was characterised alone by XPS to determine its main bond contributions and C : O ratio. Secondly, we determined the GO dose which ensures the absence of toxicity, directly exposed in vitro (human osteoblast-like cells MG-63) and in vivo (zebrafish model). In addition, GO was microinjected in the zebrafish to evaluate its effect on immune cells, quantifying the genetic expression of the main markers. Results indicated that the GO tested (C : O of 2.14, 49.50% oxidised, main bonds: C-OH, C-O-C) in a dose ≤0.25 mg mL-1 promoted MG63 cells viability percentages above 70%, and in a dose ≤0.10 mg mL-1 resulted in the absence of toxicity in zebrafish embryos. The immune response evaluation reinforced this result. Finally, the optimised GO dose (0.10 mg mL-1) was combined with polylactic acid (PLA) and CaP to obtain a 3D printed PLA:CaP:GO scaffold. Physicochemical characterisation (SEM/EDS, XRD, FT-Raman, nano-indentation) was performed and in vivo tests confirmed its biocompatibility, enabling a novel approach for bone tissue-related applications.

Cytotoxicity and Genotoxicity of Graphene Oxide Scaffold: Human Adipose Tissue Derived Mesenchymal Stromal/stem Cells (AT-MSCs) Culture

Cytotoxicity and Genotoxicity of Graphene Oxide Scaffold: Human Adipose Tissue Derived Mesenchymal Stromal/stem Cells (AT-MSCs) Culture

Driving up the Electrocatalytic Performance for Carbon Dioxide Conversion through Interface Tuning in Graphene Oxide-Bismuth Oxide Nanocomposites.

The integration of graphene oxide (GO) into nanostructured Bi2O3 electrocatalysts for CO2 reduction (CO2RR) brings up remarkable improvements in terms of performance toward formic acid (HCOOH) production. The GO scaffold is able to facilitate electron transfers toward the active Bi2O3 phase, amending for the high metal oxide (MO) intrinsic electric resistance, resulting in activation of the CO2 with smaller overpotential. Herein, the structure of the GO-MO nanocomposite is tailored according to two synthetic protocols, giving rise to two different nanostructures, one featuring reduced GO (rGO) supporting Bi@Bi2O3 core-shell nanoparticles (NP) and the other GO supporting fully oxidized Bi2O3 NP. The two structures differentiate in terms of electrocatalytic behavior, suggesting the importance of constructing a suitable interface between the nanocarbon and the MO, as well as between MO and metal.

Development of 3D printable graphene oxide based bio-ink for cell support and tissue engineering.

Tissue engineered constructs can serve as in vitro models for research and replacement of diseased or damaged tissue. As an emerging technology, 3D bioprinting enables tissue engineering through the ability to arrange biomaterials and cells in pre-ordered structures. Hydrogels, such as alginate (Alg), can be formulated as inks for 3D bioprinting. However, Alg has limited cell affinity and lacks the functional groups needed to promote cell growth. In contrast, graphene oxide (GO) can support numerous cell types and has been purported for use in regeneration of bone, neural and cardiac tissues. Here, GO was incorporated with 2% (w/w) Alg and 3% (w/w) gelatin (Gel) to improve 3D printability for extrusion-based 3D bioprinting at room temperature (RT; 25°C) and provide a 3D cellular support platform. GO was more uniformly distributed in the ink with our developed method over a wide concentration range (0.05%-0.5%, w/w) compared to previously reported GO containing bioink. Cell support was confirmed using adipose tissue derived stem cells (ADSCs) either seeded onto 3D printed GO scaffolds or encapsulated within the GO containing ink before direct 3D printing. Added GO was shown to improve cell-affinity of bioinert biomaterials by providing more bioactive moieties on the scaffold surface. 3D cell-laden or cell-seeded constructs showed improved cell viability compared to pristine (without GO) bio-ink-based scaffolds. Our findings support the application of GO for novel bio-ink formulation, with the potential to incorporate other natural and synthetic materials such as chitosan and cellulose for advanced in situ biosensing, drug-loading and release, and with the potential for electrical stimulation of cells to further augment cell function.

Generation of graphene oxide and nano-bioglass based scaffold for bone tissue regeneration

Graphene oxide (GO) offers a distinct opportunity in the field of biomedical engineering owing to its exceptionally high mechanical strength, excellent electrical conductivity, high optical transparency, and favorable biocompatibility. In this article, nanocomposite biocompatible GO-based scaffolds (chitosan/gelatin/nanobioglass/GO) Ch-G-NBG-GO were successfully fabricated through freeze drying technique (−40 °C) and evaluated for various physico-chemical and biological properties. The prepared Ch-G-NBG-GO composites have been investigated for their structural, physiochemical, and surface morphology via x-ray diffraction (XRD), high resolution scanning electron microscope, Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA), energy-dispersive x-ray Spectroscopy and, differential scanning colorimetry (DSC) respectively. The morphological analysis showed the porous interconnected network of scaffold formed. Average pore size for the Ch-G-NBG-GO scaffolds were in between 90 and 120 μm, which was very close to the control scaffolds. XRD data revealed the successful incorporation of NBG and GO and distribution across the scaffolds. Porosity of the fabricated scaffolds were in the range between 75.3% and 77.3% which was very close to the control scaffold with 79% porosity. The studies also reveal that after GO incorporation, the weight loss reduced (0.11 ± 0.02–0.095 ± 0.03), scaffolds were firmly stable at room temperature even after a long duration of 28 d. The crystallinity added to the scaffolds due to addition of GO nanoparticles improved the mechanical strength of these scaffolds. The compressive modulus changed from (5.7 to 8.51) MPa after GO addition. Swelling ratio changed drastically especially in case of Ch-NBG-90%GO (4.9 ± 0.04–4 ± 0.01). DSC and TGA data revealed the thermal stability of GO incorporated scaffolds due to the proper interaction between GO/NBG with chitosan-gelatin blend. The scaffold’s potential for bone tissue engineering was evaluated by testing its cytocompatibility for MG-63 cell line. It revealed suitable cell attachment and proliferation of cells compared to the Ch-G-NBG scaffold. MTT assay showed that Ch-G-NBG-GO scaffold below 90% GO concentration possess best biocompatibility. But in case of Ch-G-NBG-90%GO scaffold, the cell proliferation was reduced when compared to control scaffolds. Alkaline phosphatase activity suggested improved osteogenic differentiation of MG-63 cells over GO based scaffolds and this was due to the osteogenic potential of NBG and GO present in the scaffolds. Based on these results, the nano-biocomposite scaffold appears to have the potential for utilization in bone tissue restoration, replacement and regeneration.

Effects of a graphene oxide-alginate sheet scaffold on rotator cuff tendon healing in a rat model

Natural polymer scaffolds used to promote rotator cuff healing have limitations in terms of their mechanical and biochemical properties. This animal study aimed to investigate the effects of combined graphene oxide (GO) and alginate scaffold and the toxicity of GO on rotator cuff healing in a rat model. First, the mechanical properties of a GO/alginate scaffold and a pure alginate scaffold were compared. The in vitro cytotoxicity of and proliferation of human tenocytes with the GO/alginate scaffold were evaluated by CCK-8 assay. For the in vivo experiment, 20 male rats were randomly divided into two groups (n = 10 each), and supraspinatus repair was performed: group 1 underwent supraspinatus repair alone, and group 2 underwent supraspinatus repair with the GO/alginate scaffold. Biomechanical and histological analyses were performed to evaluate the quality of tendon-to-bone healing 8weeks after rotator cuff repair. The GO/alginate scaffold exhibited an increased maximum load (p = .001) and tensile strength (p = .001). In the cytotoxicity test, the cell survival rate with the GO/alginate scaffold was 102.08%. The proliferation rate of human tenocytes was no significant difference between the GO/alginate and alginate groups for 1, 3, 5, and 7days. Biomechanically, group 2 exhibited a significantly greater ultimate failure load (p < .001), ultimate stress (p < .001), and stiffness (p < .001) than group 1. The histological analysis revealed that the tendon-to-bone interface in group 2 showed more collagen fibers bridging, tendon-to-bone integration, longitudinally oriented collagen fibers, and fibrocartilage formation than in group 1. A small amount of GO added to alginate improved the mechanical properties of the scaffold without evidence of cytotoxicity. At 8 weeks after rotator cuff repair, the GO/alginate scaffold improved tendon-to-bone healing without causing any signs of toxicity in a rat model.

Crystallization Behavior and Morphology of Biodegradable Poly(ε-caprolactone)/Reduced Graphene Oxide Scaffolds.

Morphology, thermal properties and the non-isothermal melt crystallization kinetics of biodegradable poly(ε-caprolactone) (PCL)/reduced graphene oxide (rGO) scaffolds are studied with differential scanning calorimetry (DSC) at various cooling rates (5, 10, 15 and 20 °C/min). Thermally induced phase separation was used to manufacture the scaffolds (TIPS). The micrographs show a more homogeneous and defined morphology with larger pores and thicker pore walls. The melting temperature (Tm), melting enthalpy (ΔHm), crystallization enthalpy (ΔHc) and degree of crystallinity (Xc) increased with the addition of rGO, suggesting larger and more perfect crystalline structures. The degree of crystallinity increased with the presence of rGO. The crystallization peak shifted to higher temperatures as the rGO concentration increased independently of the cooling rates. The peak shifted to lower temperatures as the cooling rate increased with the same rGO composition. The values of t1/2 (time needed to reach 50% crystallization) were lower for scaffolds with rGO. The values of the crystallization rate coefficient were higher when the porous support contained rGO, which indicates that their crystallization systems are faster. The activation energy obtained with the Kissinger method decreased with the presence of rGO. The results indicate that reduced graphene oxide acts as a nucleating agent in the non-isothermal melt crystallization process. The addition of small quantities of rGO changes their thermal properties with which they can be modified for application in the field of tissue engineering.

Hydrothermal synthesis and characterization of nanocrystalline zinc vanadate (Zn2V2O7) on graphene oxide scaffolds

Transition Metal Vanadates proved to have diversified applications in photochemical, electrochemical, energy generation and storage, and fluorescence materials. Bandgap fabrication and modifying structure morphology to suit the need have been challenging. Nanocrystalline Zinc vanadate (Zn2V2O7) crystals on Graphene Oxide scaffolds were synthesized by hydrothermal method. The structure and functional bonding properties of the prepared nanomaterial was analyzed by powder X-Ray diffraction and Fourier transform infrared spectroscopy (FTIR). The bandgap is determined by UV–visible diffuse reflectance spectroscopy (DRS), and the surface charge and particle size are analyzed by dynamic light scattering analysis. Scanning Electron Microscopy equipped with a Field Emission gun is employed to check the material's morphology. The nanoparticles obtained were of size 37.1 nm, and the zeta potential of nanoparticles was found to be − 29.6 mV, which indicates the dispersion and stability of the material prepared. The specific capacitance value of the synthesized nanoparticles was 148.1 Fg−1. The active composite material was exploited as an electrode for the supercapacitor application, and it revealed that synthesized Zn2V2O7 nanoparticles lead to a possible application for future energy storage technologies.

Selective Catalytic Electro-Oxidation of Water with Cobalt Oxide in Ion Impermeable Reduced Graphene Oxide Porous Electrodes.

The direct electrolysis of seawater is greatly inhibited by the oxidation of Cl- to free chlorine, an undesirable, corrosive byproduct. To suppress the parasitic interference of Cl- and any other ion, we developed a freestanding, electrically conducting, 3D macroporous reduced graphene oxide (rGO) scaffold with cobalt oxide particles selectively deposited on the internal walls of its closed pores (with an average diameter of ∼180 μm). The pore walls act as membranes composed of stacked rGO flakes; the nanochannels between rGO layers (size <1 nm) are permeable to water and gases while preventing the diffusion of dissolved ions such as Cl-. Due to this, the catalytic particles are selectively accessible to water molecules but not to ions, allowing electrolysis to occur without chlorine evolution. The electrodes developed exhibit a stable generation of O2 from simulated seawater at pH 14, reaching a specific current density of up to 25 A g-1 during continuous electrolysis with 89-98% Faradaic efficiency, while chlorine generation is below 6 ppm h-1, the sensitivity limit of the detection method employed. The strategy here proposed can be generalized to build electrodes that are inherently selective thanks to their architecture, with catalytically active particles loaded into closed pores with selective ion transport properties.

Zinc oxide surface-functionalized PCL/graphene oxide scaffold: enhanced mechanical and antibacterial properties

Porous poly caprolactone (PCL)/graphene oxide (GO) scaffold was fabricated using both particulate and foaming agents to yield better control over pore size. Then, the surface of the PCL/GO scaffold was modified by the aminolysis method for further treatment. Needle-like zinc oxide (ZnO) was synthesized and its antibacterial activity was verified by the disk diffusion method. Next, ZnO immobilized onto the aminolyzed PCL/GO scaffold. The mechanical test demonstrated a pronounced increment of young's modulus for the PCL scaffold. It is expected that such an engineered scaffold has a high potential to be used in tissue engineering with minimal irritation due to infections during implantation.

Enabling water-based processing of graphene/alumina composites using an infiltration approach with amphiphilic triblock copolymers

Enabling the direct infiltration of freeze-cast graphene structures with water-based ceramic suspensions, otherwise prevented by graphene’s intrinsic hydrophobic behaviour, can lead to the production of hierarchical graphene/ceramic composites in a cost-effective and replicable manner. In this study, the addition of a triblock copolymer (PF127) in the formulation of water-based alumina slurries was used to allow the integration with reduced graphene oxide (rGO) scaffolds combining freeze-casting, wet chemistry processing and Spark Plasma Sintering. Wettability and infiltration tests were performed to optimise the composition of the ceramic suspension, leading to the preservation of alignment in embedded rGO scaffolds and maintaining channel widths of 5–15▒μm upon sintering at 1500∘ C.

Magnetic graphene oxide−based covalent organic frameworks as novel adsorbent for extraction and separation of triazine herbicides from fruit and vegetable samples

A novel magnetic graphene oxide−based covalent organic frameworks, was prepared initially by grafting two monomers, tris(4−aminophenyl)amine and 2, 4, 6−triformylphloroglucinol onto Fe3O4 nanoparticles attached to graphene oxide scaffolds. It exhibited a regular core−shell spherical structure, super paramagnetism, and desirable adsorbability for five triazine herbicides, and was thus served as adsorbent of magnetic solid−phase extraction. An analytical strategy coupled magnetic solid phase extraction with UHPLC−MS/MS was then developed for the determination of triazine herbicide residues in fruit and vegetable samples. The validation results revealed good linearity in the concentration range of 0.01–200 μg L−1(r≥0.9925). LODs of the method were in the range of 0.01–0.05 μg kg−1, LOQs in the range of 0.05–0.2 μg kg−1 and recoveries ranged from 72.3 to 112.8%. The results showed that the prepared adsorbent provided desirable adsorption capacity of triazine herbicides, demonstrating great potential in the detection of trace triazine herbicides in complex food matrices.

Impact of rGO-coated PEEK and lattice on bone implant

The composite coating can effectively inhibit bacterial proliferation and promote the expression of bone-building genes in-vitro. Therefore, a novel production was used to produce poly-ether-ether-ketone, and reduced graphene oxide (PEEK-rGO) scaffolds with ratios of 1–3%, combining a different lattice for a bone implant. An inexpensive method was developed to prepare the new coatings on the PEEK scaffold with reduced graphene oxide (rGO). Mechanical testing, data analysis and cell culture tests for in-vitro biocompatibility scaffold characterisation for the PEEK composite were conducted. Novel computation microanalysis of four-dimensional (4D) printing of microstructure of PEEK-rGO concerning the grain size and three dimensional (3D) morphology was influenced by furrow segmentation of grains cell growth on the composite, which was reduced from an average of 216–155 grains and increased to 253 grains on the last day. The proposed spherical nanoparticles cell grew with time after dispersed PEEK nanoparticles in calcium hydroxyapatite (cHAp) grains. Also, the mechanical tests were carried out to validate the strength of the new composites and compare them to that of a natural bone. The established 3D-printed PEEK composite scaffolds significantly exhibited the potential of bone implants for biomimetic heterogeneous bone repair.

In-situ generated Li3N/Li-Al alloy in reduced graphene oxide framework optimizing ultra-thin lithium metal electrode for solid-state batteries

Optimization of lithium metal anode is a pivotal part in facilitating the evolution of next-generation high energy density solid-state lithium metal batteries (LMBs). However, the practical application of lithium anode in solid-state LMBs is limited by uncontrollable dendrite growth and the poor interfacial contact with solid electrolyte. Herein, a 40 µm thin lithium composite anode based on the AlN-embedded reduced graphene oxide (rGO) scaffold synthesized via one-step molten lithium infusion is proposed. The resulting lithiophilic Li-Al alloy and high ion-conductive Li3N in situ constructed the lithium ion diffusing highways inside electrode, enabling a well-oriented Li deposition and effectively inhibiting the dendrite growth. Combined with in-situ polymerization and Li3N-modified solid electrolyte interphase (SEI), the composite anodes can prolong the lifespan of symmetric cell to 2100 h at 0.2 mA cm−2/0.2 mAh cm−2 in carbonate-based solid polymer electrolytes. Moreover, LAG||LiFePO4 full cells also excelled in cycling capability and rate performance. This modified electrode offers a promising synergistic solution for designing high-performance solid-state LMBs.