Evaluation of contact angle and mechanical properties of resin monomers filled with graphene oxide nanofibers

Abstract This in vitro study synthesized hybrid nanofibers embedded in graphene oxide (GO) and incorporated them into experimental resin composite monomers to evaluate their physical-mechanical properties. Inorganic-organic hybrid nanofibers were produced with precursor solutions of 1% wt. GO-filled Poly (d,l-lactide, PLA) fibers and scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) characterized the morphology and chemical composition of the spun fibers. Resin composite monomers were developed and a total of 5% nanofibers were incorporated into the experimental materials. Three groups were developed: G1 (control resin monomers), G2 (resin monomers/PLA nanofibers), and G3 (resin monomers/inorganic-organic hybrid nanofibers). Contact angle (n=3), flexural strength (n=22), elastic modulus (n=22), and Knoop hardness (n=6) were evaluated. The mean of the three indentations was obtained for each sample. The normality of data was assessed by QQ Plot with simulated envelopes and analyzed by Welch's method (p<0.05). Overall, SEM images showed the regular shape of nanofibers but were non-aligned. Compositional analysis from EDS (n=6) revealed the presence of carbon and oxygen (present in GO composition) and Si from the functionalization process. The results of contact angle (°) and hardness (Kg/mm2) for each group were as follow, respectively: G1 (59.65±2.90; 37.48±1.86a), G2 (67.99±3.93; 50.56±1.03b) and G3 (62.52±7.40; 67.83±1.01c). The group G3 showed the highest Knoop hardness values (67.83 kg/mm2), and the flexural strength of all groups was adversely affected. The experimental resin composite composed of hybrid nanofibers with GO presented increased hardness values and hydrophilic behavior.

Resumo Este estudo in vitro sintetizou nanofibras híbridas embebidas em óxido de grafeno (GO), incorporando-as à uma resina composta experimental de monômeros para avaliar suas propriedades físico-mecânicas. Nanofibras híbridas inorgânica-orgânicas foram produzidas com soluções precursoras de fibras poli (d, l-lactídeo, PLA) preenchidas com GO a 1% em peso e microscopia eletrônica de varredura (MEV) e espectroscopia de raio-X de energia dispersiva (EDS) caracterizaram a morfologia e composição química das fibras. Monômeros de resina composta foram desenvolvidos e um total de 5% de nanofibras foi incorporado aos materiais experimentais. Três grupos foram desenvolvidos: G1 (monômeros de resina controle), G2 (monômeros de resina/ nanofibras de PLA) e G3 (monômeros de resina/nanofibras híbridas inorgânico-orgânicas). Ângulo de contato (n=3), resistência à flexão (n=22), módulo de elasticidade (n=22) e dureza Knoop (n=6) foram avaliados. A média das três endentações foi obtida para cada amostra. A normalidade dos dados foi avaliada pelo QQ Plot com envelopes simulados e analisada pelo método de Welch (p<0,05). No geral, as imagens de MEV mostraram forma regular de nanofibras, mas não alinhadas. A análise composicional de EDS (n=6) revelou a presença de carbono e oxigênio (presentes na composição do GO) e Si resultante do processo de funcionalização. Os resultados do ângulo de contato (°) e dureza (Kg/mm2) para cada grupo foram os seguintes, respectivamente: G1 (59,65±2,90; 37,48±1,86a), G2 (67,99±3,93; 50,56±1,03b) e G3 (62,52±7,40; 67,83±1,01c). G3 apresentou os maiores valores de dureza Knoop (67,83 kg/mm2), e a resistência à flexão de todos os grupos foi prejudicada. A resina composta experimental composta por nanofibras híbridas com GO apresentou maiores valores de dureza e comportamento hidrofílico.

Effect of graphene-oxide-modified osteon-like concentric microgrooved surface on the osteoclastic differentiation of macrophages / 华西口腔医学杂志

OBJECTIVES@#This study aimed to investigate the effect of new biomimetic micro/nano surfaces on the osteoclastic differentiation of RAW264.7 macrophages by simulating natural osteons for the design of concentric circular structures and modifying graphene oxide (GO).@*METHODS@#The groups were divided into smooth titanium surface group (SS), concentric microgrooved titanium surface group (CMS), and microgroove modified with GO group (GO-CMS). The physicochemical properties of the material surfaces were studied using scanning electron microscopy (SEM), contact-angle measurement, atomic force microscopy, X-ray photoelectron spectroscopy analysis, and Raman spectroscopy. The effect of the modified material surface on the cell biological behavior of RAW264.7 was investigated by cell-activity assay, SEM, and laser confocal microscopy. The effect on the osteoclastic differentiation of macrophages was investiga-ted by tartrate-resistant acid phosphatase (TRAP) immunofluorescence staining and quantitative real-time polymerase chain reaction (qRT-PCR) experiments.@*RESULTS@#Macrophages were arranged in concentric circles along the microgrooves, and after modification with GO, the oxygen-containing groups on the surface of the material increased and hydrophilicity increased. Osteoclasts in the GO-CMS group were small in size and number and had the lowest TRAP expression. Although it promoted the proliferation of macrophages in the GO-CMS group, the expression of osteoclastic differentiation-related genes was lower than that in the SS group, and the difference was statistically significant (P<0.05).@*CONCLUSIONS@#Concentric circular microgrooves restricted the fusion of osteoclasts and the formation of sealing zones. Osteomimetic concentric microgrooves modified with GO inhibited the osteoclastic differentiation of RAW 264.7 macrophages.

Exposure to specific far-infrared ray based on gra-phene film promotes exercise capacity and glucose metabolism via AMPK / 中国药理学与毒理学杂志

OBJECTIVE AMPK activator,act as exer-cise mimetics,effective in preventing or ameliorating met-abolic diseases,including obesity and diabetes.Systemic activating of AMPK represents an important therapeutic strategy to treat metabolic diseases.However,whether far-infrared(FIR)hyperthermia therapy could be used as exercise mimetic to realize wide-ranging metabolic regu-lation,and its underling mechanisms remain unclear.METHODS The mice were subjected to hyperthermia in the FIR chamber(30±1)℃for 14 d.Exercise endurance was determined using a treadmill.Blood flow were mea-sured by the laser speckle contrast imaging.Combina-tion of microbiomic and metabolomic analysis,diversity of microbiota and metabolic profiling in muscle were detected.The microbiota disorder model via treatment with different cocktails of antibiotics(ABX).RESULTS The material characterization shows that the graphene synthesized by chemical vapour deposition(CVD)is dif-ferent from carbon fi ber,with single-layer structure and high electrothermal transform efficiency.The emission spectra generated by graphene-FIR device would maxi-mize matching those adsorbed by tissues(≈8.0 μm).Gra-phene-FIR improves core and epidermal temperature,and increases blood flow in femoral muscle and abdo-men.The diversity of gut microbiota was increased by graphene-FIR exposure.Graphene-FIR reduced the bac-teroidetes/firmicutes(B/F)ratio and increased the abun-dance of short-chain fatty acids(SCFA)-producing bac-teria,including Allobaculum,Blautia and Anaerostipes.Additionally,graphene-FIR stimulated the expression of SCFAs-sensing receptor(GPR 43),p-AMPK Thr172 and GLUT4,and increased the AMP/ATP ratio,thus enhanc-ing muscle glucose uptake.Metabolomic analyses revealed the significant changes in 25 metabolites,with twenty increased(eg.creatinine and phosphate)and five decreased(eg.lactic acid),and the marked impact of five metabolic pathways,including galactose metabo-lism,glycolysis,gluconeogenesis,fatty acid biosynthesis,butanoate metabolism,pyruvate metabolism.Further-more,a microbiota disorder model also demonstrates that the graphene-FIR effectively restore the exercise endurance with enhanced p-AMPK and GLUT4.CON-CLUSION Our results provide convincing evidence that graphene-based FIR therapy promoted exercise capacity and glucose metabolism via AMPK in gut-muscle axis.These novel insights into graphene-FIR therapy suggest a potential as an exercise mimetic for the treatment of metabolic disease in clinical.

Identification of Traditional Chinese Medicine Seahorses Using Graphene Oxide-based Fluorescent Sensing Technology / 中国实验方剂学杂志

ObjectiveTo establish a method for seahorse identification based on graphene oxide fluorescence sensing technology， and to provide a new research idea for identification of traditional Chinese medicine. MethodThe fluorophore FAM was labeled at the 5' end of the specificity upstream primer Ja-F of Hippocampus japonicus as the nucleic acid probe FAM-ssDNA （single strand DNA）. The recognition site of RNA polymerase Ⅱ was added to its specific downstream primer Ja-R as Ja-R1. The seahorse samples were amplified with Ja-F/Ja-R1 primers， and the ssDNA of H. japonicus was obtained by reverse transcription of the amplification products using vitro transcription method. The 20 μL nucleic acid probe FAM-ssDNA （500 nmol·L-1） was incubated at 90 ℃ for 5 min， and was gradually cooled to room temperature. Different volume of graphene oxide solution （100 mg·L-1） and Tris hydroxymethyl amino methane HCl （Tris-HCl） buffer （50 mmol·L-1） were added into each probe solution to make a final reaction volume of 1 mL. The fluorescence intensity of each sample was measured after mixing and placing different times at room temperature away from the light. So that the most appropriate graphene oxide concentration and reaction time were screened for constructing the best nucleic acid probe-graphene oxide biosensor. Adding probe complementary sequence FAM-ssDNA-match solution into the nucleic acid probe-graphene oxide solution， the fluorescence intensity of the reaction mixture was measured after being placed different times at room temperature. Therefore， the optimal reaction time of fluorescence recovery was screened and the feasibility of the sensor was tested. The sensitivity was detected via adding ddH2O as the blank control and different concentration H. japonicus ssDNA into each nucleic acid probe-graphene oxide solution， respectively. Finally， the commercial hippocampal were identified using the optimal experimental condition， and the feasibility of this method for the identification of Chinese medicinal materials was verified. ResultThe fluorescence of 1 mL reaction mixture including 10 nmol·L-1 nucleic acid probe FAM-ssDNA and 12 mg·L-1 go solution for 20 min at room temperature away from the light could be completely quenched. Feasibility test of the biosensor showed that when probe complementary sequence FAM-ssDNA-match solution （final concentration 90 nmol·L-1） was added to the biosensor solution and reacted 1 h reaction at room temperature， the fluorescence signal was significantly enhanced. Sensitivity test showed that the minimum concentration of ssDNA detected by this method was about 10 mg·L-1. This method was used to detect commercial seahorses， and only H. japonicus samples had obvious fluorescence signal. ConclusionThe graphene oxide-based fluorescent sensing technology could be used for zoological origin survey of commercial hippocampus.

Photocatalytic destruction of Escherichia coli in water over rGO/TiO2 nanocomposites

In the present study, Graphene-TiO2 catalysts are prepared by solvothermal method with varied graphene concentrations (1%, 2.5% and 5%). The prepared nanocomposites were characterized by FTIR, Raman and TEM. The photocatalytic activity towards the destruction of Escherichia coli in water under UV and UV-visible irradiations were studied. Graphene-TiO2 nano composite destructs the bacteria significantly at higher rates than unmodified TiO2 and graphene. The results indicates that, at the beginning, the inactivation of E. coli cells is more due to the generation of reactive oxygen species (ROS) like, OH, H2O2, and O2– . Among all samples, the nano composite containing 2.5 wt.% of graphene exhibits a complete E. coli destruction in a minimum irradiation time of 15 and 20 min under UV–Visible and UV light irradiation respectively. The high photocatalytic activity is achieved with the optimum loading concentration of 2.5 wt. % graphene on titania

Analysis of anticancer compound,indole-3-carbinol,in broccoli using a new ultrasound-assisted dispersive-filter extraction method based on poly(deep eutectic solvent)-graphene oxide nanocomposite / 药物分析学报

Indole-3-carbinol(I3C),an important anticancer compound found in broccoli,has attracted considerable attention.The rapid extraction and accurate analysis of I3C in the pharmaceutical industry in broccoli is challenging as I3C is unstable at low pH and high temperature.In this study,a rapid,accurate,and low-cost ultrasound-assisted dispersive-filter extraction(UADFE)technique based on poly(deep eutectic solvent)-graphene oxide(PDES-GO)adsorbent was developed for the isolation and analysis of I3C in broccoli for the first time.PDES-GO with multiple adsorption interactions and a fast mass transfer rate was synthesized to accelerate adsorption and desorption.UADFE was developed by combining dispersive solid-phase extraction(DSPE)and filter solid-phase extraction(FSPE)to realize rapid extraction and separation.Based on the above two strategies,the proposed PDES-GO-UADFE method coupled with high-performance liquid chromatography(HPLC)allowed the rapid(15-16 min),accurate(84.3％-96.4％),and low-cost(adsorbent:3.00 mg)analysis of I3C in broccoli and was superior to solid-phase extraction,DSPE,and FSPE methods.The proposed method showed remarkable linearity(r=0.9998;range:0.0840-48.0 μg/g),low limit of quantification(0.0840 μg/g),and high precision(relative standard deviation≤5.6％).Therefore,the PDES-GO-UADFE-HPLC method shows significant potential in the field of pharmaceutical analysis for the separation and analysis of anti-cancer compounds in complex plant samples.

Accurate construction of cell membrane biomimetic graphene nanodecoys via purposeful surface engineering to improve screening efficiency of active components of traditional Chinese medicine

Biomimetic nanoengineering presents great potential in biomedical research by integrating cell membrane (CM) with functional nanoparticles. However, preparation of CM biomimetic nanomaterials for custom applications that can avoid the aggregation of nanocarriers while maintaining the biological activity of CM remains a challenge. Herein, a high-performance CM biomimetic graphene nanodecoy was fabricated via purposeful surface engineering, where polyethylene glycol (PEG) was used to modifying magnetic graphene oxide (MGO) to improve its stability in physiological solution, so as to improve the screening efficiency to active components of traditional Chinese medicine (TCM). With this strategy, the constructed PEGylated MGO (PMGO) could keep stable at least 10 days, thus improving the CM coating efficiency. Meanwhile, by taking advantage of the inherent ability of HeLa cell membrane (HM) to interact with specific ligands, HM-camouflaged PMGO showed satisfied adsorption capacity (116.2 mg/g) and selectivity. Finally, three potential active components, byakangelicol, imperatorin, and isoimperatorin, were screened from Angelica dahurica, whose potential antiproliferative activity were further validated by pharmacological studies. These results demonstrated that the purposeful surface engineering is a promising strategy for the design of efficient CM biomimetic nanomaterials, which will promote the development of active components screening in TCM.

Biological and physico-mechanical properties of poly (methyl methacrylate) enriched with graphene oxide as a potential biomaterial / Propiedades físicas-mecánicas-biológicas del poli (metilmetacrilato) enriquecido con óxido de grafeno como potencial biomaterial

Objective: To determine the cytotoxicity and effects of graphene oxide (GO) on cellular proliferation of gingival-fibroblasts, pulp-dental cells and human osteoblasts in culture, and to determine the physical, mechanical and biological properties of poly (methyl methacrylate) (PMMA) enriched with GO. Material and Methods: The GO was characterized with SEM. Cytotoxicity and cell proliferation were determined by the MTT bioassay. The physical mechanical tests (flexural strength and elastic modulus) were carried out with a universal testing machine. Sorption and solubility were determined by weighing before and after drying and immersion in water. Porosity was evaluated by visual inspection. Data were analyzed with Student's t-test and Tukey's posthoc ANOVA. Results: The GO has a heterogeneous morphology and a particle size of 66.67±64.76 µm. GO has a slight to no-cytotoxicity (>50-75% viability) at 1-30 days, and at 24 hours incubation of PMMA with GO significantly stimulates osteoblasts (45±8%, p<0.01). The physical and mechanical properties of PMMA with GO increase considerably without altering sorption, solubility and porosity. Conclusion: GO alone or with PMMA has an acceptable biocompatibility, could contribute to cell proliferation, cell regeneration and improve the physical mechanical properties of PMMA.

Objective: To determine the cytotoxicity and effects of graphene oxide (GO) on cellular proliferation of gingival-fibroblasts, pulpdental cells and human osteoblasts in culture, and to determine the physical, mechanical and biological properties of poly (methyl methacrylate) (PMMA) enriched with GO. Material and Methods: T he G O w as c haracterized with SEM. Cytotoxicity and cell proliferation were determined by the MTT bioassay. The physical-mechanical tests (flexural strength and elastic modulus) were carried out with a universal testing machine. Sorption and solubility were determined by weighing before and after drying and immersion in water. Porosity was evaluated by visual inspection. Data were analyzed with Student's t-test and Tukey's post-hoc ANOVA. Results: The GO has a heterogeneous morphology and a particle size of 66.67±64.76 ?m. GO has a slight to no-cytotoxicity (>50-75% viability) at 1-30 days, and at 24 hours incubation of PMMA with GO significantly stimulates osteoblasts (45±8%, p<0.01). The physical and mechanical properties of PMMA with GO increase considerably without altering sorption, solubility and porosity. Conclusion: GO alone or with PMMA has an acceptable biocompatibility, could contribute to cell proliferation, cell regeneration and improve the physical-mechanical properties of PMMA.

Perspectivas y aplicaciones reales del grafeno después de 16 años de su descubrimiento / Perspectives and real applications of graphene at 16 years after its breakthrough / Perspectivas e aplicações reais do grafeno após 16 anos de sua descoberta

Resumen A 16 años del gran descubrimiento del grafeno los focos de atención vuelven a estar en este material con el reporte de su comportamiento superconductor dependiendo del apilado de sus capas. Sin embargo, su nombre durante estos últimos años no solo se ha relacionado a la superconductividad, sino que ha sido relacionado con una diversidad muy amplia de aplicaciones, en disciplinas muy diversas, entre las que cabe mencionar: materiales opto-electrónicos, electrodos para catálisis, dispositivos para tratamiento de desechos, biosensores, entre otros. Esto ha hecho que un gran número de grupos de investigación se hayan interesado no solo en estudiar sus propiedades, sino también en investigar nuevos métodos sintéticos que puedan ser escalables a niveles industriales, sin perder sus propiedades electrónicas y mecánicas. A pesar de los numerosos estudios y los recursos invertidos en grafeno no todas las aplicaciones han llegado a ser una realidad, en esta revisión se muestran algunas de las más exitosas.

Abstract 16 years after the great discovery of graphene, the focus and attention are again on this material after the report of its superconducting behavior depending on the stacking of its layers. The graphene has not only been related to superconductivity but has also been related to a wide diversity of applications, in very diverse disciplines. Among them, we can mention: Opto-electronic materials, electrodes for catalysis, devices for waste-water treatment, biosensors, batteries, and solar cells. This has caused a large number of research groups to be interested not only in the study of its properties, but also in the research of new synthetic methods that can be scaled to industrial levels, without losing its electronic and mechanical properties. Despite numerous studies and resources invested in graphene, not all applications have become a reality, some of the most successful are shown in this review.

Resumo 16 anos após a grande descoberta do grafeno, o foco e as atenções voltam a ser neste material com o relato de seu comportamento supercondutor em função do empilhamento de suas camadas. No entanto, seu nome nos últimos anos não tem sido apenas relacionado à supercondutividade, mas tem sido relacionado a uma diversidade muito ampla de aplicações, em disciplinas muito diversas. Entre eles podemos citar: materiais optoeletrônicos, eletrodos para catálise, dispositivos para tratamento de águas residuais, biossensores, baterias e células solares. Isso fez com que um grande número de grupos de pesquisa se interessassem não apenas em estudar suas propriedades, mas muitas pesquisas também foram feitas na geração de métodos sintéticos que pudessem ser dimensionados para níveis industriais, sem perder suas propriedades eletrônicas e mecânicas. Apesar dos inúmeros estudos e recursos investidos em grafeno, nem todas as aplicações se tornaram realidade, algumas das mais bem-sucedidas são apresentadas nesta revisão.

Study on the adsorption of inflammatory cytokines and blood compatibility of graphene oxide electrostatic self-assembled polyester material / 中国输血杂志

【Objective】 To investigate the removal efficacy of inflammatory cytokines and blood compatibility of modified PBTNF. 【Methods】 Acrylic acid (AA) was firstly UV-grafted onto the surface of PBTNF to negatively charge the surface of the material. Subsequently, the three positively charged polyelectrolytes, DA, PEI, and CS were respectively electrostatic self-assembled with GO on the surface of PBTNF, forming two layers of film with GO as the outer layer: PBTNF-(DA/GO)2, PBTNF-(PEI/GO)2, PBTNF-(CS/GO)2. 【Results】 Scanning electron microscopy results showed that compared with the PBTNF grafted with AA, the adhesion of particles was observed on the surface of the three modified materials, and the photo shows that the color of the material surface was deepened after electrostatic self-assembly. The results of wettability showed that the surface hydrophilicity was significantly improved, indicating that the electrostatic self-assembled membrane was successfully immobilized on the surface of PBTNF. The removal efficiency (%) of IL-1β for PBTNF-(DA/GO)2, PBTNF-(PEI/GO)2 and PBTNF-(CS/GO)2 were 69.00±7.36 vs -2.35±2.69 vs -1.59±3.26 (P<0.05). The removal efficiency of IL-6 (%) were 40.15±1.86 vs -13.46±5.72 vs -1.21±3.41 (P<0.05). The removal efficiency of IL-8 (%) were 96.90±0.97 vs 17.84±11.74 vs 43.68±17.38 (P<0.05). The removal efficiency of TNF-α (%) was 44.46±2.50 vs 14.90±7.12 vs 20.64±1.22 (P<0.05). Plasma protein adsorption results (total protein, immunoglobulin G, albumin) and red blood cell deformability index showed that there was no statistical difference among the three modified PBTNFs and the control group (P>0.05). Although the red blood cell osmotic fragility (g/L) of the three modified PBTNFs is higher than that of the former: control group vs PBTNF-(DA/GO)2 vs PBTNF-(PEI/GO)2 vs PBTNF-(CS/GO)2: 4.39±0.05 vs 4.62±0.02 vs 4.48±0.03 vs 4.90±0.03 (P<0.05), the hemolysis rate (%) of them were all less than 5%, and PBTNF-(DA/GO)2 performed the lowest hemolysis rate which was (0.03±0.01)% (compared with PBTNF-(PEI/GO)2, P<0.05). The coagulation function test results showed that compared with the control group, the fibrinogen (g/L) of the three modified PBTNFs had no statistical difference (P>0.05); the activated partial thrombo plastin time (S) slightly extended, but all within the normal range of clinical standard; and the prothrombin time (S) of PBTNF-(CS/GO)2 was prolonged(P<0.05). 【Conclusion】 Among the three positively charged polyelectrolytes, including DA, PEI, and CS, PBTNF-(DA/GO)2 performed the best removal rate of inflammatory cytokines, and the blood compatibility evaluation results showed that PBTNF-(DA/GO)2 had no significant effect on red blood cells and coagulation function. Consequently, in the study of inflammatory cytokines adsorption, DA is expected to be the optimal polyelectrolyte assembling with GO for further research.

A sensitive electrochemical detection of metronidazole in synthetic serum and urine samples using low-cost screen-printed electrodes modified with reduced graphene oxide and C60 / 药物分析学报

Monitoring the concentration of antibiotics in body fluids is essential to optimizing the therapy and minimizing the risk of bacteria resistance,which can be made with electrochemical sensors tailored with appropriate materials.In this paper,we report on sensors made with screen-printed electrodes(SPE)coated with fullerene(C60),reduced graphene oxide(rGO)and Nafion(NF)(C60-rGO-NF/SPE)to determine the antibiotic metronidazole(MTZ).Under optimized conditions,the C60-rGO-NF/SPE sensor exhibited a linear response in square wave voltammetry for MTZ concentrations from 2.5×10-7 to 34×10-6 mol/L,with a detection limit of 2.1×10-7 mol/L.This sensor was also capable of detecting MTZ in serum and urine,with recovery between 94％and 100％,which are similar to those of the standard chromatographic method(HPLC-UV).Because the C60-rGO-NF/SPE sensor is amenable to mass pro-duction and allows for MTZ determination with simple principles of detection,it fulfills the requirements of therapeutic drug monitoring programs.

Synthesis and electrochemical properties of environmental free L-glutathione grafted graphene oxide/ZnO nanocomposite for highly selective piroxicam sensing / 药物分析学报

A simple and reliable strategy was proposed to engineer the glutathione grafted graphene oxide/ZnO nanocomposite(glutathione-GO/ZnO)as electrode material for the high-performance piroxicam sensor.The prepared glutathione-GO/ZnO nanocomposite was well characterized by X-ray diffraction(XRD),Fourier transform infrared spectrum(FTIR),X-ray photoelectron spectroscopy(XPS),field emission scanning electron microscopy(FE-SEM),cyclic voltammetry(CV),electrochemical impedance spectros-copy(EIS)and differential pulse voltammetry(DPV).The novel nanocomposite modified electrode showed the highest electrocatalytic activity towards piroxicam(oxidation potential is 0.52 V).Under controlled experimental parameters,the proposed sensor exhibited good linear responses to piroxicam concentrations ranging from 0.1 to 500 μM.The detection limit and sensitivity were calculated as 1.8 nM and 0.2 μA/μM·cm2,respectively.Moreover,it offered excellent selectivity,reproducibility,and long-term stability and can effectively ignore the interfering candidates commonly existing in the pharmaceutical tablets and human fluids even at a higher concentration.Finally,the reported sensor was successfully employed to the direct determination of piroxicam in practical samples.

Effects of Oridonin-loaded Chitosan Graphene Oxide on the Proliferation and Apoptosis of A 549 Cells / 中国药房

OBJECTIVE：To study the effects of chitosan graphene oxide car rier（CS-GO）loaded with oridonin （CS-GO- oridonin）on the proliferation and apoptosis of human lung cancer A 549 cells. METHODS ：Taking A 549 cells as objects ，the survival rate of cells were detected by CCK- 8 method after treated with different concentrations of CS-GO （3，6，12，24，48 μg/mL）and CS-GO-oridonin loaded with same mass of oridonin （3，6，12，24，48 μg/mL，by the weight of oridonin ，the same below）. IC 50 of CS-GO-oridonin was calculated. The cell morphology were observed by microscope after treated with CS-GO and CS-GO-oridonin（both 32 μg/mL）for 2，4，10，24 h. The uptake of CS-GO ，oridonin，CS-GO-orionin（all 32 μg/mL）by cells was observed with fluorescence labeling method. The apoptosis of cells and the content of ROS were observed by flow cytometry after treated with different concentrations of CS-GO （16，32，64 μg/mL）and CS-GO-oridonin （16，32，64 μg/mL）. The expression of anti-apoptosis related proteins （Mcl-1，Bax and Bak ）were detected by Western blot. RESULTS ：After treated with different concentrations of CS-GO ，the survival rate of cells was still above 90％ ；after treated with different concentrations of CS-GO-oridonin，the survival rate of cells showed a downward trend ，and was significantly lower than that of CS-GO group （P＜ 0.01）；IC50 of CS-GO-oridonin was 32.61 μg/mL. After CS-GO treatment，the cell morphology did not change significantly ；after CS-GO-oridonin treatment ，the cells shrunk and fell off in clusters ，and the suspended matter increased ；the fluorescence of oridonin and CS-GO-orionin taken up by cells was enhanced than CS-GO. Compared with blank group ，there was no significant change in the apoptosis rate ，the content of ROS and the expression of apoptosis-related protein in 16，32，64 μg/mL CS-GO groups（P＞0.05）；apoptosis rate ，the content of ROS ，the protein expression of Bax and Bak in 16，32，64 μg/mL CS- GO-oridonin groups were increased significantly ，while the protein expression of Mcl- 1 were decreased significantly. Above indexes were significantly high er or lower than the same concentration CS-GO group （P＜0.05）. CONCL USIONS：CS-GO dose not affect the proliferation and apoptosis of A 549 cells；CS-GO-oridonin has obvious inhibition and apoptosis promoting effect on cells ，which may be related to increasing ROS production and regulating the expression of apoptosis related proteins.

Effects of graphene on the proliferation, migration and morphology of dental pulp stem cells / 口腔疾病防治

Objective@# To investigate the effects of graphene on the proliferation, migration and cell morphology of dental pulp stem cells (DPSCs).@*Methods@#Graphene powder was prepared by the oxidation-reduction method, and a 0.5 mg/mL graphene dispersion was prepared. Raman spectroscopy and atomic force microscopy were used to characterize the structure and surface morphology of graphene. DPSCs were isolated and cultured in vitro. MTT assay was used to detect the effects of different concentrations of graphene dispersions (0, 1, 5, 10, 20, 50, 100 μg/mL) on the proliferation and wound healing assay was used to detected the migration abilities of DPSCs. The effects of graphene on the morphology of DPSCs were observed by immunofluorescence staining. @*Results @# In the present study, compared with the control group (0 μg/mL), the proliferation of DPSCs in the 100 μg/mL group was inhibited at 72 h (P < 0.05), and the proliferation of DPSCs in the other groups was not significantly affected (P > 0.05). Graphene dispersions at 10 and 20 μg/mL promoted the migration of DPSCs (P < 0.05). After being cultured in 20 μg/mL graphene dispersions for 3 days, the DPSCs showed a large and orderly cytoskeletal structure, and the spread area of cells was not significantly different from that of the control group (0 μg/mL) (P > 0.05), while some cells had the morphological characteristics of nerve cells.@* Conclusion @# Graphene has good biocompatibility and is expected to be a suitable material for tissue engineering within fitting concentration.

Removal of Shield Needles from Graphene Oxide Thrombus and Preparation / 中国医疗器械杂志

Atherosclerosis is a chronic inflammatory disease commonly seen in clinical practice. It can lead to thickening of vascular intima, occlusion of lumen stenosis and thrombosis, leading to angina pectoris, hypertension, myocardial infarction and other diseases, posing a serious threat to human life and health. This study provides a method for removing shield needles from graphene oxide thrombus and its preparation. The graphene oxide shield needle mainly includes flexible rotating shaft, radial flexible rod, rotating needle, adsorption main pipe and dosing main pipe, laser measuring device, high definition camera and other structures, which has the following advantages:firstly, it achieves multi-angle rotation grinding thrombosis, precise rotation grinding, avoids vascular damage and infection; secondly, thrombolytic drugs can be applied in the process of rotary grinding and small thrombus can be adsorbed to effectively avoid secondary embolization of blood vessels; thirdly, it a coating of graphene oxide on a rotating needle, which protects against bacteria and infection. This study has practical reference value for the development of thrombotherapy and the application of graphene in the medical field.

Overoxidized poly(3,4-ethylenedioxythiophene)-gold nanoparticles-graphene-modified electrode for the simultaneous detection of dopamine and uric acid in the presence of ascorbic acid / 药物分析学报

An innovative,ternary nanocomposite composed of overoxidized poly(3,4-ethylenedioxythiophene)(OPEDOT),gold nanoparticles (AuNPs),and electrochemically reduced graphene oxide (ERGO) was prepared on a glassy carbon electrode (GCE) (OPEDOT-AuNPs-ERGO/GCE) through homogeneous chemical reactions and heterogeneous electrochemical methods.The morphology,composition,and structure of this nanocomposite were characterized by transmission electron microscopy,scanning electron microscopy,X-ray diffraction,and X-ray photoelectron spectroscopy.The electrochemical properties of the OPEDOT-AuNPs-ERGO/GCE were investigated by cyclic voltammetry using potassium ferricyanide and hexaammineruthenium(Ⅲ) chloride redox probe systems.This modified electrode shows excellent electro-catalytic activity for dopamine (DA) and uric acid (UA) under physiological pH conditions,but inhibits the oxidation of ascorbic acid (AA).Linear voltammetric responses were obtained when DA concentrations of approximately 4.0-100 μM and UA concentrations of approximately 20-100 μM were used.The detection limits (S/N=3) for DA and UA were 1.0 and 5.0 μ.M,respectively,under physiological conditions and in the presence of 1.0 mM of AA.This developed method was applied to the simultaneous detection of DA and UA in human urine,where satisfactory recoveries from 96.7％ to 105.0％were observed.This work demonstrates that the developed OPEDOT-AuNPs-ERGO ternary nano-composite,with its excellent ion-selectivity and electro-catalytic activity,is a promising candidate for the simultaneous detection of DA and UA in the presence of AA in physiological and pathological studies.

Biosynthesis of Graphene and Investigation of Antibacterial Activity of Graphene-parthenium hysterophorous Nanocomposite

Abstract There is a great interest to use carbon-based material like graphene and graphene oxide in biomedical applications due to its flexibility to be functionalized with bio-active molecules. Herein, graphene and graphene-based nanocomposites were biosynthesized by liquid-phase exfoliation of graphite using aqueous extract of Parthenium hysterophorous (P-H) as a surfactant. A set of five thin film samples of graphene was prepared from graphene suspension by vacuum filtration method. Samples were characterized by UV-vis spectroscopy, Raman spectroscopy, SEM, and XRD, which revealed successful synthesis of graphene. Graphene/P-H(G/P-H) nanocomposites comprising varied ratios of graphene and P-H were prepared and their antibacterial activity was investigated by agar well diffusion method. The experimental results indicated that G/P-H nanocomposite have higher antibacterial activity than graphene alone, and bioactivity of G/P-H nanocomposite was found to be controlled by the fraction of graphene in the composite.

El grafeno en la rehabilitación bucal y su comportamiento biológico: caso clínico / Graphene in oral rehabilitation and its biological behavior: a clinical case

El grafeno y sus derivados son muy utilizados en ciencia y tecnología por los beneficios que otorgan sus propiedades fisicoquímicas. En el área de la salud en particular, se destacan sus propiedades biológicas debido a su elevada biocompatibilidad, interacción celular y su actividad antibacteriana. La incorporación de grafeno en ciertos materiales permite obtener un material combinado con propiedades mejoradas. Un ejemplo de ello es la incorporación industrial de óxido de grafeno en metacrilato de metilo para generar un polímero (PMMA) mejorado, no solo desde el punto de vista mecánico, sino también una notoria ventaja en la respuesta biológica de los tejidos blandos. Este artículo describe el caso clínico de un paciente de 70 años, que concurrió a la consulta buscando alternativas de tratamiento para mejorar la retención y estabilidad de las prótesis para optimizar la función masticatoria, una alternativa que impacte positivamente sobre su calidad de vida. El plan de tratamiento contempló el reemplazo de las prótesis removibles por prótesis híbridas en ambos maxilares, confeccionadas con PMMA modificado industrialmente con óxido de grafeno, previa colocación de cinco implantes en cada arco (AU)

Graphene and its derivatives are widely used in science and technology due to the benefits provided by their physicochemical properties. In the health area, specifically, its biological properties stand out, due to its high biocompatibility, cellular interaction, and its antibacterial activity. The incorporation of graphene in certain materials allows obtaining a combined material with improved properties. An example of this is the industrial incorporation of graphene oxide in methyl methacrylate, to generate an improved polymer (PMMA), not only from a mechanical point of view, but also a notable advantage in the biological response of soft tissues. This article describes the clinical case of a 70-year-old patient, who attended the consultation looking for treatment alternatives to improve the retention and stability of the prostheses to optimize the masticatory function, or an alternative that had a positive impact on their quality of lifetime. The treatment plan contemplated the replacement of removable prostheses with hybrid prostheses in both jaws, made with PMMA industrially modified with graphene oxide, after placing five implants in each arch (AU)

Graphene Conjugated Usnic Acid Nano-Formulation For The Treatment Of Topical Fungal Infection

Objective: The study aims to investigate the antifungal response of the dug usnic acid with the carrier graphene. Methods: Nano-precipitation method by sonication was adopted to formulate the conjugate. SEM test was performed to check the shape and average size of the conjugate. FTIR test was performed for the chemical interaction between the drug and the carrier. Ointment was prepared by the fusion method and the viscosity test was performed by Brookfield viscometer. Spreadability test was performed by slide method. Animal activity was performed to confirm the antifungal effect of the formulated nano-conjugate. Statistical analysis was done by Anova. Results: SEM study shows that the conjugate is in the nano range and possess a spherical shape. FTIR study shows no interaction between the drug and the carrier. The result of in vitro drug release study shows that the conjugate posses a higher drug release rate as compared to the drug alone. Topical drug administration is more suitable for the treatment of the fungal infection, so the nano-conjugate was incorporated into the ointment by geometric mixing. The viscosity and the spreadability test were performed on the different formulations of the ointment and the suitable one was selected for the topical administration. Anti-fungal study had been performed on the Wistar albino rats for 6 d. Skin culture of rats was performed for the formation of the fungal colonies. Statistical analysis by Anova gives p<0.001. It was found that the normal form of usnic acid, graphene and the nano form both possess anti-fungal activity as 3/6 and 2/6 experimental animals are cured by normal formulation and nano-formulation. Conclusion: The present anti-fungal study revealed that the nano-form of the conjugate possess higher anti-fungal activity than the normal formulation of usnic acid with graphene.

Effect of Addition of Graphene and Carbon Nanotubes on Flexural Strength of Polymethylmethacrylate- A Comparative In-Vitro Study.

Heat polymerized denture base resins are a popular choice in prosthodontics for fabrication of partial or complete dentures, cranioplasts, hybrid implant prosthesis, and maxillofacial prosthetics. The wide utility of these materials can be attributed to their favourable mechanical properties. Despite the popularity gained by them, clinicians often encounter suboptimal flexural strength resulting in frequent fracture of the fabricated prosthesis. The purpose of this study was to compare the flexural strength (FS) of Polymethylmethacrylate (PMMA) modified using micro-additions of Multi-Walled Carbon Nanotubes (MWCNT) and Graphene Oxide (GO) as fillers respectively with PMMA having no micro-additions.METHODSThis is an in-vitro comparative study. Sixty samples of PMMA were divided in three groups of 20 each containing: Group 1: no micro additions (control group), Group 2: 0.5 wt% MWCNT in monomer of PMMA resin, Group 3: 0.5 wt% GO in monomer of PMMA resin. MWCNT and Graphene oxide were dispersed in Methylmethacrylate (monomer) respectively by ultrasonic agitation. Monomer and polymer were mixed in the ratio of 1:3. The samples were heat polymerised. Finished samples were subjected to 3-point bending test for checking their flexural strength. The results were statistically compared using one-way ANOVA followed by post hoc Bonferroni corrected paired T test for inter-group comparisons.RESULTSThe highest mean Flexural Strength of 36.5 MPa was recorded in Group 2 (MWCNT) followed by 31.55 MPa in Group 1 (control) and the least 29.72 MPa in Group 3 (Graphene Oxide) respectively. Intergroup comparisons revealed significant difference between Group 1 (control) & Group 2 (MWCNT) with “p=0.011” and between Group 2 (MWCNT) & Group 3 (Graphene Oxide) with “p<0.001”. However, no significant difference was found between Group 1 (control) and Group 3 (Graphene Oxide) with “p= 0.803”.CONCLUSIONSThe addition of 0.5 wt% MWCNT to PMMA is an easy, effective and economical step towards increasing the flexural strength and thus, decreasing the incidence of prosthesis fracture, when compared to 0.5 wt% graphene oxide or no micro additions.