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1.
Nano Lett ; 24(4): 1284-1293, 2024 Jan 31.
Artículo en Inglés | MEDLINE | ID: mdl-38230643

RESUMEN

Despite its effectiveness in eliminating cancer cells, ferroptosis is hindered by the high natural antioxidant glutathione (GSH) levels in the tumor microenvironment. Herein, we developed a spatially asymmetric nanoparticle, Fe3O4@DMS&PDA@MnO2-SRF, for enhanced ferroptosis. It consists of two subunits: Fe3O4 nanoparticles coated with dendritic mesoporous silica (DMS) and PDA@MnO2 (PDA: polydopamine) loaded with sorafenib (SRF). The spatial isolation of the Fe3O4@DMS and PDA@MnO2-SRF subunits enhances the synergistic effect between the GSH-scavengers and ferroptosis-related components. First, the increased exposure of the Fe3O4 subunit enhances the Fenton reaction, leading to increased production of reactive oxygen species. Furthermore, the PDA@MnO2-SRF subunit effectively depletes GSH, thereby inducing ferroptosis by the inactivation of glutathione-dependent peroxidases 4. Moreover, the SRF blocks Xc- transport in tumor cells, augmenting GSH depletion capabilities. The dual GSH depletion of the Fe3O4@DMS&PDA@MnO2-SRF significantly weakens the antioxidative system, boosting the chemodynamic performance and leading to increased ferroptosis of tumor cells.


Asunto(s)
Ferroptosis , Nanopartículas , Neoplasias , Humanos , Compuestos de Manganeso/farmacología , Óxidos , Antioxidantes , Glutatión , Dióxido de Silicio , Línea Celular Tumoral , Neoplasias/tratamiento farmacológico , Microambiente Tumoral
2.
Angew Chem Int Ed Engl ; 62(14): e202216188, 2023 03 27.
Artículo en Inglés | MEDLINE | ID: mdl-36722433

RESUMEN

Due to non-specific strong nano-bio interactions, it is difficult for nanocarriers with permanent rough surface to cross multiple biological barriers to realize efficient drug delivery. Herein, a camouflaged virus-like-nanocarrier with a transformable rough surface is reported, which is composed by an interior virus-like mesoporous SiO2 nanoparticle with a rough surface (vSiO2 ) and an exterior acid-responsive polymer. Under normal physiological pH condition, the spikes on vSiO2 are hidden by the polymer shell, and the non-specific strong nano-bio interactions are effectively inhibited. While in the acidic tumor microenvironment, the nanocarrier sheds the polymer camouflage to re-expose its rough surface. So, the retention ability and endocytosis efficiency of the nanocarrier are great improved. Owing to it's the dynamically variable rough surface, the rationally designed nanocarrier exhibits extended blood-circulation-time and enhanced tumor accumulation.


Asunto(s)
Portadores de Fármacos , Nanopartículas , Dióxido de Silicio , Sistemas de Liberación de Medicamentos , Polímeros , Doxorrubicina/farmacología , Línea Celular Tumoral
3.
J Am Chem Soc ; 144(9): 3892-3901, 2022 03 09.
Artículo en Inglés | MEDLINE | ID: mdl-35191672

RESUMEN

As one of the most important parameters of the nanomotors' motion, precise speed control of enzyme-based nanomotors is highly desirable in many bioapplications. However, owing to the stable physiological environment, it is still very difficult to in situ manipulate the motion of the enzyme-based nanomotors. Herein, inspired by the brakes on vehicles, the near-infrared (NIR) "optical brakes" are introduced in the glucose-driven enzyme-based mesoporous nanomotors to realize remote speed regulation for the first time. The novel nanomotors are rationally designed and fabricated based on the Janus mesoporous nanostructure, which consists of the SiO2@Au core@shell nanospheres and the enzymes-modified periodic mesoporous organosilicas (PMOs). The nanomotor can be driven by the biofuel of glucose under the catalysis of enzymes (glucose oxidase/catalase) on the PMO domain. Meanwhile, the Au nanoshell at the SiO2@Au domain enables the generation of the local thermal gradient under the NIR light irradiation, driving the nanomotor by thermophoresis. Taking advantage of the unique Janus nanostructure, the directions of the driving force induced by enzyme catalysis and the thermophoretic force induced by NIR photothermal effect are opposite. Therefore, with the NIR optical speed regulators, the glucose-driven nanomotors can achieve remote speed manipulation from 3.46 to 6.49 µm/s (9.9-18.5 body-length/s) at the fixed glucose concentration, even after covering with a biological tissue. As a proof of concept, the cellar uptake of the such mesoporous nanomotors can be remotely regulated (57.5-109 µg/mg), which offers great potential for designing smart active drug delivery systems based on the mesoporous frameworks of this novel nanomotor.


Asunto(s)
Nanoestructuras , Dióxido de Silicio , Sistemas de Liberación de Medicamentos , Glucosa , Glucosa Oxidasa , Nanoestructuras/química , Dióxido de Silicio/química
4.
J Biochem Mol Toxicol ; 36(2): e22957, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34796584

RESUMEN

The hypothalamic paraventricular nucleus (PVN) is a specific center in the brain that regulates gastric mucosal injury following gastric ischemia-reperfusion (GI-R) injury. This study aimed to investigate whether autophagy-lysosome dysfunction in the PVN tissues of GI-R rats is involved in the gastric injury, and the underlying molecular mechanisms. The rat model of GI-R was established by clamping the celiac artery for 30 min and reperfusion for different hours (1, 3, and 6 h). The gastric injury was evaluated by hematoxylin and eosin staining of the stomach and the gastric mucosal index. The autophagy-lysosome dysfunction in the PVN was evaluated by the protein levels of LC3 II and Beclin-1 (markers for autophagosome activity) and the activity of acid phosphatase (a representative lysosomal enzyme). Immunohistochemical staining of ionized calcium-binding adaptor molecule 1 in the PVN was performed to evaluate microglial activation. Reactive oxygen species (ROS) content and phosphorylated γ-aminobutyric acid B receptor (p-GABAB R) expression in the PVN were also examined. The results revealed that, in GI-R rats, the shorter the reperfusion duration, the more severe the gastric mucosal damage. The autophagy-lysosome dysfunction exhibited by GI-R rats further enhanced microglial activation, ROS production, p-GABAB R expression, and gastric injury. In addition, activating microglial cells increased ROS production, p-GABAB R expression, and gastric injury in GI-R rats, while inhibiting microglial activation resulted in the opposite results. Taken together, autophagy-lysosome dysfunction induced by GI-R aggravated the gastric injury by inducing microglia activation.


Asunto(s)
Autofagia , Mucosa Gástrica/metabolismo , Lisosomas/metabolismo , Microglía/metabolismo , Núcleo Hipotalámico Paraventricular/metabolismo , Daño por Reperfusión/metabolismo , Gastropatías/metabolismo , Animales , Mucosa Gástrica/patología , Lisosomas/patología , Masculino , Microglía/patología , Núcleo Hipotalámico Paraventricular/patología , Ratas , Ratas Sprague-Dawley , Daño por Reperfusión/patología , Gastropatías/patología
5.
J Am Chem Soc ; 2020 Nov 03.
Artículo en Inglés | MEDLINE | ID: mdl-33141579

RESUMEN

Bending and folding are important stereoscopic geometry parameters of one-dimensional (1D) nanomaterials, yet the precise control of them has remained a great challenge. Herein, a surface-confined winding assembly strategy is demonstrated to regulate the stereoscopic architecture of uniform 1D mesoporous SiO2 (mSiO2) nanorods. Based on this brand-new strategy, the 1D mSiO2 nanorods can wind on the surface of 3D premade nanoparticles (sphere, cube, hexagon disk, spindle, rod, etc.) and inherit their surface topological structures. Therefore, the mSiO2 nanorods with a diameter of ∼50 nm and a variable length can be bent into arc shapes with variable radii and radians, as well as folded into 60, 90, 120, and 180° angular convex corners with controllable folding times. Additionally, in contrast to conventional core@shell structures, this winding structure induces partial exposure and accessibility of the premade nanoparticles. The functional nanoparticles can exhibit large accessible surface and efficient energy exchanges with the surroundings. As a proof of concept, winding-structured CuS&mSiO2 nanocomposites are fabricated, which are made up of a 100 nm CuS nanosphere and the 1D mSiO2 nanorods with a diameter of ∼50 nm winding the nanosphere in the perimeter. The winding structured nanocomposites are demonstrated to have fourfold photoacoustic imaging intensity compared with the conventional core@shell nanostructure with an inaccessible core because of the greatly enhanced photothermal conversion efficiency (increased by ∼30%). Overall, our work paves the way to the design and synthesis of 1D nanomaterials with controllable bending and folding, as well as the formation of high-performance complex nanocomposites.

6.
Analyst ; 142(18): 3341-3345, 2017 Sep 08.
Artículo en Inglés | MEDLINE | ID: mdl-28825062

RESUMEN

A novel and facile ratiometric fluorescence method for evaluating Cu2+ has been developed based on coumarin-labeled single-stranded DNA (C-ssDNA) coupled with the Cu2+-induced oxidation of o-phenylenediamine (OPD). By combining the microdialysis technique, the ratiometric fluorescence method has also been successfully exploited to monitor the cerebral Cu2+ in the rat brain, promising new opportunities for studying the cerebral Cu2+-associated physiological and pathological events.


Asunto(s)
Cerebro/diagnóstico por imagen , Cobre/química , Cumarinas/química , ADN/química , Fenilendiaminas/química , Animales , Fluorescencia , Oxidación-Reducción , Ratas
7.
Anal Chem ; 88(23): 11647-11653, 2016 12 06.
Artículo en Inglés | MEDLINE | ID: mdl-27934126

RESUMEN

A simple and novel method for evaluating antioxidants in complex biological fluids has been developed based on the interaction of dye-labeled single-strand DNA (ssDNA) and polydopamine (PDA). Due to the interaction between ssDNA and PDA, the fluorescence of dye-labeled ssDNA (e.g., FITC-ssDNA, as donor) can be quenched by PDA (as acceptor) to the fluorescence "off" state through Förster resonance energy transfer (FRET). However, in the presence of various antioxidants, such as glutathione (GSH), ascorbic acid (AA), cysteine (Cys), and homocysteine (Hcys), the spontaneous oxidative polymerization reaction from DA to PDA would be blocked, resulting in the freedom of FITC-ssDNA and leading to the fluorescence "on" state. The sensing system shows great sensitivity for the monitoring of antioxidants in a fluorescent "turn on" format. The new strategy also exhibits great selectivity and is free from the interferences of amino acids, metal ions and the biological species commonly existing in brain systems. Moreover, by combining the microdialysis technique, the present method has been successfully applied to monitor the dynamic changes of the striatum antioxidants in rat cerebrospinal microdialysates during the normal/ischemia/reperfusion process. This work establishes an effective platform for in vivo monitoring antioxidants in cerebral ischemia model, and promises new opportunities for the research of brain chemistry, neuroprotection, physiological, and pathological events.


Asunto(s)
Antioxidantes/análisis , Corteza Cerebral/química , ADN/química , Colorantes Fluorescentes/química , Indoles/química , Polímeros/química , Animales , Ácido Ascórbico/análisis , Isquemia Encefálica , Cisteína/análisis , Glutatión/análisis , Homocisteína/análisis , Ratas , Espectrometría de Fluorescencia
8.
Nano Lett ; 13(6): 2902-7, 2013 Jun 12.
Artículo en Inglés | MEDLINE | ID: mdl-23638876

RESUMEN

Semiconducting nanomaterials are being intensively studied as active elements in bioelectronic devices, with the aim of improving spatial resolution. Yet, the consequences of size-reduction on fundamental noise limits, or minimum resolvable signals, and their impact on device design considerations have not been defined. Here, we address these key issues by quantifying the size-dependent performance and limiting factors of graphene (Gra) transducers under physiological conditions. We show that suspended Gra devices represent the optimal configuration for cardiac extracellular electrophysiology in terms of both transducer sensitivity, systematically ~5× higher than substrate-supported devices, and forming tight bioelectronic interfaces. Significantly, noise measurements on free-standing Gra together with theoretical calculations yield a direct relationship between low-frequency 1/f noise and water dipole-induced disorders, which sets fundamental sensitivity limits for Gra devices in physiological media. As a consequence, a square-root-of-area scaling of Gra transducer sensitivity was experimentally revealed to provide a critical design rule for their implementation in bioelectronics.


Asunto(s)
Técnicas Biosensibles , Grafito/química , Semiconductores , Límite de Detección
9.
J Am Heart Assoc ; 13(7): e033893, 2024 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-38533976

RESUMEN

BACKGROUND: Increasing evidence suggests a higher propensity for acute myocardial infarction (MI) in patients with psoriasis. However, the shared mechanisms underlying this comorbidity in these patients remain unclear. This study aimed to explore the shared genetic features of psoriasis and MI and to identify potential biomarkers indicating their coexistence. METHODS AND RESULTS: Data sets obtained from the gene expression omnibus were examined using a weighted gene coexpression network analysis approach. Hub genes were identified using coexpression modules and validated in other data sets and through in vitro cellular experiments. Bioinformatics tools, including the Human microRNA Disease Database, StarBase, and miRNet databases, were used to construct a ceRNA network and predict potential regulatory mechanisms. By applying weighted gene coexpression network analysis, we identified 2 distinct modules that were significant for both MI and psoriasis. Inflammatory and immune pathways were highlighted by gene ontology enrichment analysis of the overlapping genes. Three pivotal genes-Src homology and collagen 1, disruptor of telomeric silencing 1-like, and feline leukemia virus subgroup C cellular receptor family member 2-were identified as potential biomarkers. We constructed a ceRNA network that suggested the upstream regulatory roles of these genes in the coexistence of psoriasis and MI. CONCLUSIONS: As potential therapeutic targets, Src homology and collagen 1, feline leukemia virus subgroup C cellular receptor family member 2, and disruptor of telomeric silencing 1-like provide novel insights into the shared genetic features between psoriasis and MI. This study paves the way for future studies focusing on the prevention of MI in patients with psoriasis.


Asunto(s)
Infarto del Miocardio , Psoriasis , Humanos , Regulación de la Expresión Génica , Redes Reguladoras de Genes , Psoriasis/genética , Infarto del Miocardio/genética , Biomarcadores/metabolismo , Colágeno/metabolismo , Perfilación de la Expresión Génica/métodos
10.
Food Funct ; 14(12): 5653-5662, 2023 Jun 19.
Artículo en Inglés | MEDLINE | ID: mdl-37249386

RESUMEN

Aims: Non-alcoholic fatty liver disease (NAFLD) is a widely prevalent hepatic disorder resulting in a high risk of adverse prognosis, and its presence has been considered a cause or an outcome of metabolic syndrome. But the relative factors and mechanism of NAFLD are still unclear. The aim of this study is to explore the association between iron status indicators and NAFLD as well as liver fibrosis. Methods: This study evaluated whether serum iron status indicators are independently related to the risk of NAFLD. The independent variable was each one of the iron status indicators (iron intake, ferritin, iron, unsaturated iron binding force (UIBC), total iron binding capacity (TIBC), transferrin saturation, transferrin receptor, hemoglobin, and mean cell hemoglobin), and the dependent variables were NAFLD and advanced liver fibrosis. A multivariable logistic regression analysis and subgroup analysis were performed to evaluate the association between iron status indicators and NAFLD as well as liver fibrosis. Results: A total of 3727 patients were included. After adjusting for other covariates in multiple logistic regression models, the serum ferritin, UIBC, TIBC, and hemoglobin had a significant positive association with the NAFLD (odds ratio [OR] = 1.16, 95% confidence interval [CI]: 1.09, 1.23; 1.31, 95% CI: 1.06, 1.62; 1.82, 95% CI: 1.23, 2.67; 2.67, 95% CI: 1.48, 4.82, separately), and the risk of NAFLD diagnosed by VCTE or ALT/AST further increased in the fourth quartile group of serum ferritin (diagnosed by VCTE OR = 1.93, 95% CI: 1.49, 2.50; diagnosed by ALT/AST OR = 5.76, 95% CI: 3.96, 8.38). Moreover, the main positive correlation between serum ferritin and NAFLD was found in females, participants aged >41 years, with no diabetes. Conclusion: Our results indicated that iron status indicators were closely associated with the occurrence of advanced liver fibrosis, which may indicate that iron status indicators could be potential biomarkers of NAFLD and advanced liver fibrosis.


Asunto(s)
Enfermedad del Hígado Graso no Alcohólico , Femenino , Adulto , Humanos , Enfermedad del Hígado Graso no Alcohólico/complicaciones , Hierro , Estudios Transversales , Encuestas Nutricionales , Cirrosis Hepática/epidemiología , Ferritinas , Hemoglobinas
11.
Nano Lett ; 11(2): 767-71, 2011 Feb 09.
Artículo en Inglés | MEDLINE | ID: mdl-21218829

RESUMEN

By combining atomic force microscopy and trans-port measurements, we systematically investigated effects of thermal annealing on surface morphologies and electrical properties of single-layer graphene devices fabricated by electron beam lithography on silicon oxide (SiO(2)) substrates. Thermal treatment above 300 °C in vacuum was required to effectively remove resist residues on graphene surfaces. However, annealing at high temperature was found to concomitantly bring graphene in close contact with SiO(2) substrates and induce increased coupling between them, which leads to heavy hole doping and severe degradation of mobilities in graphene devices. To address this problem, a wet-chemical approach employing chloroform was developed in our study, which was shown to enable both intrinsic surfaces and enhanced electrical properties of graphene devices. Upon the recovery of intrinsic surfaces of graphene, the adsorption and assisted fibrillation of amyloid ß-peptide (Aß1-42) on graphene were electrically measured in real time.


Asunto(s)
Cristalización/métodos , Grafito/química , Nanoestructuras/química , Nanoestructuras/ultraestructura , Nanotecnología/métodos , Dióxido de Silicio/química , Adsorción , Dureza , Calor , Sustancias Macromoleculares/química , Ensayo de Materiales , Conformación Molecular , Tamaño de la Partícula , Soluciones , Propiedades de Superficie
12.
Front Cardiovasc Med ; 9: 974353, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36440001

RESUMEN

Background: Acute myocardial infarction (AMI), one of the most severe and fatal cardiovascular diseases, is a major cause of morbidity and mortality worldwide. Macrophages play a critical role in ventricular remodeling after AMI. The regulatory mechanisms of the AMI progression remain unclear. This study aimed to identify hub regulators of macrophage-related modules and provide translational experiments with potential therapeutic targets. Materials and methods: The GSE59867 dataset was downloaded from the Gene Expression Omnibus (GEO) database for bioinformatics analysis. The expression patterns of 22 types of immune cells were determined using CIBERSORT. GEO2R was used to identify differentially expressed genes (DEGs) through the limma package. Then, DEGs were clustered into different modules, and relationships between modules and macrophage types were analyzed using weighted gene correlation network analysis (WGCNA). Further functional enrichment analysis was performed using significantly associated modules. The module most significantly associated with M2 macrophages (Mϕ2) was chosen for subsequent analysis. Co-expressed DEGs of AMI were identified in the GSE123342 and GSE97320 datasets and module candidate hub genes. Additionally, hub gene identification was performed in GSE62646 dataset and clinical samples. Results: A total of 8,760 DEGs were identified and clustered into ten modules using WGCNA analysis. The blue and turquoise modules were significantly related to Mϕ2, and 482 hub genes were discerned from two hub modules that conformed to module membership values > 0.8 and gene significance values > 0.25. Subsequent analysis using a Venn diagram assessed 631 DEGs in GSE123342, 1457 DEGs in GSE97320, and module candidate hub genes for their relationship with Mϕ2 in the progression of AMI. Finally, four hub genes (CSF2RB, colony stimulating factor 2 receptor subunit beta; SIGLEC9, sialic acid-binding immunoglobulin-like lectin 9; LRRC25, leucine-rich repeat containing 25; and CSF3R, colony-stimulating factor-3 receptor) were validated to be differentially expressed and to have high diagnostic value in both GSE62646 and clinical samples. Conclusion: Using comprehensive bioinformatics analysis, we identified four novel genes that may play crucial roles in the pathophysiological mechanism of AMI. This study provides novel insights into the impact of macrophages on the progression of AMI and directions for Mϕ2-targeted molecular therapies for AMI.

13.
Nano Lett ; 10(5): 1864-8, 2010 May 12.
Artículo en Inglés | MEDLINE | ID: mdl-20373779

RESUMEN

We report enhanced performance of suspended graphene field effect transistors (Gra-FETs) as sensors in aqueous solutions. Etching of the silicon oxide (SiO(2)) substrate underneath graphene was carried out in situ during electrical measurements of devices, which enabled systematic comparison of transport properties for same devices before and after suspension. Significantly, the transconductance of Gra-FETs in the linear operating modes increases 1.5 and 2 times when the power of low-frequency noise concomitantly decreases 12 and 6 times for hole and electron carriers, respectively, after suspension of graphene in solution from the SiO(2) substrate. Suspended graphene devices were further demonstrated as direct and real-time pH sensors, and complementary pH sensing with the same nanodevice working as either a p-type or n-type transistor was experimentally realized by offsetting the electrolyte gate potential in solution. Our results highlight the importance to quantify fundamental parameters that define resolution of graphene-based bioelectronics and demonstrate that suspended nanodevices represent attractive platforms for chemical and biological sensors.


Asunto(s)
Técnicas Biosensibles/instrumentación , Grafito/química , Nanoestructuras/química , Nanotecnología/instrumentación , Transistores Electrónicos , Diseño de Equipo , Análisis de Falla de Equipo , Concentración de Iones de Hidrógeno , Nanoestructuras/ultraestructura , Sensibilidad y Especificidad
14.
Medicine (Baltimore) ; 99(2): e18649, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31914047

RESUMEN

RATIONALE: Cerebral sinovenous thrombosis (CVT) associated with inflammatory bowel disease (IBD) is infrequent, but clinically nonnegligible due to its high disability and fatality rates. PATIENT CONCERNS: A 12-year-old child with newly developed ulcerative colitis (UC) suffered from a sudden left-sided hemiparesis and numbness. DIAGNOSES: Cerebral sinovenous thrombosis due to ulcerative colitis was diagnosed in this girl. INTERVENTIONS: The patient was treated with blood transfusion and anticoagulation therapy. Digital subtraction angiography (DSA) and urokinase thrombolysis were implemented followed. OUTCOMES: The patient achieved a complete recovery of limb functions and did not present any other stroke recurrences at follow-up a year later. LESSONS: CVT in UC is a serious condition and can occur in the children and adolescents. Rapidly diagnosis of this complication of IBD and apply anticoagulant therapy early can contribute to avoiding a potentially fatal outcome.


Asunto(s)
Colitis Ulcerosa/complicaciones , Trombosis Intracraneal/complicaciones , Anticoagulantes/uso terapéutico , Transfusión Sanguínea , Niño , Femenino , Humanos , Trombosis Intracraneal/terapia
15.
J Neuropathol Exp Neurol ; 79(10): 1100-1114, 2020 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-32888019

RESUMEN

To investigate the underlying mechanism of lncRNA BC083743 in regulating the proliferation of Schwann cells (SCs) and axon regeneration after sciatic nerve crush (SNC), we used a rat model. Sciatic function index and the atrophy ratio of gastrocnemius muscle were evaluated. The relationship among BC083743, miR-103-3p, and brain-derived neurotrophic factor (BDNF) and their regulation mechanism in the repair of SNC were investigated using in vivo and in vitro experiments. The expression changes of BC083743 were positively associated with that of BDNF following SNC, but the expression changes of miR-103-3p were inversely associated with that of BDNF. The SC proliferation and BDNF expression could be promoted by overexpression of BC083743, while they were inhibited by a miR-103-3p mimic. In addition, BC083743 interacted with and regulated miR-103-3p, thereby promoting BDNF expression and SC proliferation. BC083743 overexpression also promoted axon regeneration through miR-103-3p. In vivo experiments also indicated that BC083743 overexpression promoted the repair of SNC. In conclusion, LncRNA BC083743 promotes SC proliferation and the axon regeneration through miR-103-3p/BDNF after SNC.


Asunto(s)
Factor Neurotrófico Derivado del Encéfalo/genética , Proliferación Celular/genética , MicroARNs/genética , Regeneración Nerviosa/genética , ARN Largo no Codificante/genética , Células de Schwann , Animales , Axones/metabolismo , Axones/patología , Regulación de la Expresión Génica/fisiología , Masculino , Compresión Nerviosa , Ratas , Ratas Sprague-Dawley , Nervio Ciático/lesiones
17.
Nanoscale ; 6(14): 8387-91, 2014 Jul 21.
Artículo en Inglés | MEDLINE | ID: mdl-24942365

RESUMEN

We studied the self-assembly of trimesic acid on single- and few-layer graphene supported by SiO2 substrates. A scanning tunneling microscope operated under ambient conditions was utilized to image supramolecular networks of trimesic acid at liquid-graphene interfaces. Trimesic acid can self-assemble into large-scale, highly ordered adlayers on graphene surfaces. Phase transition of the trimesic acid adlayer from a close-packed structure to a porous chicken-wire structure was observed by changing from single- to few-layer graphene, which was attributed to the modulation of molecule-graphene interactions by the layer number of graphene. The guest-induced phase transition of trimesic acid by complexation with coronene on single-layer graphene further confirms that supramolecular networks on graphene can be rationally tailored with sub-nanometer resolution by balancing between intermolecular vs. molecule-graphene interactions. We further investigated the effects of trimesic acid adlayers on the electronic transport properties of graphene transistors. The adsorption of trimesic acid induces p-doping and defects in the adlayers cause scattering of charge carriers in single-layer graphene.

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