scholarly journals Targeted fluorescence imaging enhanced by 2D materials: a comparison between 2D MoS2 and graphene oxide

2016 ◽  
Vol 52 (60) ◽  
pp. 9418-9421 ◽  
Author(s):  
Donghao Xie ◽  
Ding-Kun Ji ◽  
Yue Zhang ◽  
Jun Cao ◽  
Hu Zheng ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Fluorescence Imaging ◽  
2D Materials ◽  
Tissue Imaging ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Receptor Targeting

2D MoS2 enhances the receptor-targeting cell and tissue imaging ability of a fluorophore-labeled ligand in a concentration-dependent manner.

scholarly journals Robust Magnetized Graphene Oxide Platform for In Situ Peptide Synthesis and FRET-Based Protease Detection

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5275
Author(s):  
Seongsoo Kim ◽  
Sang-Myung Lee ◽  
Je Pil Yoon ◽  
Namhun Lee ◽  
Jinhyo Chung ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Peptide Synthesis ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Resonance Energy ◽  
Precursor Solution ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Biomarker Analysis

Graphene oxide (GO)/peptide complexes as a promising disease biomarker analysis platform have been used to detect proteolytic activity by observing the turn-on signal of the quenched fluorescence upon the release of peptide fragments. However, the purification steps are often cumbersome during surface modification of nano-/micro-sized GO. In addition, it is still challenging to incorporate the specific peptides into GO with proper orientation using conventional immobilization methods based on pre-synthesized peptides. Here, we demonstrate a robust magnetic GO (MGO) fluorescence resonance energy transfer (FRET) platform based on in situ sequence-specific peptide synthesis of MGO. The magnetization of GO was achieved by co-precipitation of an iron precursor solution. Magnetic purification/isolation enabled efficient incorporation of amino-polyethylene glycol spacers and subsequent solid-phase peptide synthesis of MGO to ensure the oriented immobilization of the peptide, which was evaluated by mass spectrometry after photocleavage. The FRET peptide MGO responded to proteases such as trypsin, thrombin, and β-secretase in a concentration-dependent manner. Particularly, β-secretase, as an important Alzheimer’s disease marker, was assayed down to 0.125 ng/mL. Overall, the MGO platform is applicable to the detection of other proteases by using various peptide substrates, with a potential to be used in an automated synthesis system operating in a high throughput configuration.

scholarly journals Receptor-targeting fluorescence imaging and theranostics using a graphene oxide based supramolecular glycocomposite

2015 ◽  
Vol 3 (47) ◽  
pp. 9182-9185 ◽  
Author(s):  
Ding-Kun Ji ◽  
Yue Zhang ◽  
Yi Zang ◽  
Wang Liu ◽  
Xiongwen Zhang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Fluorescence Imaging ◽  
Receptor Targeting

We describe the construction of a supramolecular, graphene oxide (GO)-based glycocomposite for receptor-targeting theranostics.

scholarly journals Interaction of Graphene Oxide Modified with Linear and Branched PEG with Monocytes Isolated from Human Blood

Nanomaterials ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 126
Author(s):  
Pavel Khramtsov ◽  
Maria Bochkova ◽  
Valeria Timganova ◽  
Anton Nechaev ◽  
Sofya Uzhviyuk ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Immune Cells ◽  
Human Peripheral Blood ◽  
Oxide Surface ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Composition And Structure ◽  
Luminescent Signal ◽  
Ros Formation ◽  
The Impact

Multiple graphene-based therapeutics have recently been developed, however potential risks related to the interaction between nanomaterials and immune cells are still poorly understood. Therefore, studying the impact of graphene oxide on various populations of immune cells is of importance. In this work, we aimed to investigate the effects of PEGylated graphene oxide on monocytes isolated from human peripheral blood. Graphene oxide nanoparticles with lateral sizes of 100–200 nm and 1–5 μm were modified with linear and branched PEG (GO-PEG). Size, elemental composition, and structure of the resulting nanoparticles were characterized. We confirmed that PEG was successfully attached to the graphene oxide surface. The influence of GO-PEG on the production of reactive oxygen species (ROS), cytokines, phagocytosis, and viability of monocytes was studied. Uptake of GO-PEG by monocytes depends on PEG structure (linear or branched). Branched PEG decreased the number of GO-PEG nanoparticles per monocyte. The viability of monocytes was not altered by co-cultivation with GO-PEG. GO-PEG decreased the phagocytosis of Escherichia coli in a concentration-dependent manner. ROS formation by monocytes was determined by measuring luminol-, lucigenin-, and dichlorodihydrofluorescein-dependent luminescence. GO-PEG decreased luminescent signal probably due to inactivation of ROS, such as hydroxyl and superoxide radicals. Some types of GO-PEG stimulated secretion of IL-10 by monocytes, but this effect did not correlate with their size or PEG structure.

scholarly journals Cytotoxic Effect of Graphene Oxide Nanoribbons on Escherichia coli

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1339
Author(s):  
Shirong Qiang ◽  
Zhengbin Li ◽  
Li Zhang ◽  
Dongxia Luo ◽  
Rongyue Geng ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Graphene Oxide ◽  
Cytotoxic Effect ◽  
Lactic Dehydrogenase ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
E Coli ◽  
Graphene Oxide Nanoribbons ◽  
Graphene Derivatives

The biological and environmental toxicity of graphene and graphene derivatives have attracted great research interest due to their increasing applications. However, the cytotoxic mechanism is poorly understood. Here, we investigated the cytotoxic effect of graphene oxide nanoribbons (GORs) on Escherichia coli (E. coli) in an in vitro method. The fabricated GORs formed long ribbons, 200 nm wide. Based on the results of the MTT assay and plate-culture experiments, GORs significantly inhibited the growth and reproduction of E. coli in a concentration-dependent manner. We found that GORs stimulated E. coli to secrete reactive oxygen species, which then oxidized and damaged the bacterial cell membrane. Moreover, interaction between GORs and E. coli cytomembrane resulted in polysaccharide adsorption by GORs and the release of lactic dehydrogenase. Furthermore, GORs effectively depleted the metal ions as nutrients in the culture medium by adsorption. Notably, mechanical cutting by GORs was not obvious, which is quite different from the case of graphene oxide sheets to E. coli.

scholarly journals Synthesis and Characterization of Sulfur and Sulfur-Selenium Nanoparticles Loaded on Reduced Graphene Oxide and Their Antibacterial Activity against Gram-Positive Pathogens

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 191
Author(s):  
Rashmi Niranjan ◽  
Saad Zafar ◽  
Bimlesh Lochab ◽  
Richa Priyadarshini
Keyword(s):  
Antibacterial Activity ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Antimicrobial Agents ◽  
Antibacterial Properties ◽  
Spherical Shape ◽  
Dependent Manner ◽  
Gram Positive ◽  
Concentration Dependent Manner ◽  
Reduced Graphene

Resistance to antimicrobial agents in Gram-positive bacteria has become a major concern in the last decade. Recently, nanoparticles (NP) have emerged as a potential solution to antibiotic resistance. We synthesized three reduced graphene oxide (rGO) nanoparticles, namely rGO, rGO-S, and rGO-S/Se, and characterized them using X-ray diffraction (PXRD), Raman analysis, and thermogravimetric analysis. Transmission electron microscopy confirmed spherical shape nanometer size S and S/Se NPs on the rGO surface. Antibacterial properties of all three nanomaterials were probed against Gram-positive pathogens Staphylococcus aureus and Enterococcus faecalis, using turbidometeric and CFU assays. Among the synthesized nanomaterials, rGO-S/Se exhibited relatively strong antibacterial activity against both Gram-positive microorganism tested in a concentration dependent manner (growth inhibition >90% at 200 μg/mL). Atomic force microscopy of rGO-S/Se treated cells displayed morphological aberrations. Our studies also revealed that rGO composite NPs are able to deposit on the bacterial cell surface, resulting in membrane perturbation and oxidative stress. Taken together, our results suggest a possible three-pronged approach of bacterial cytotoxicity by these graphene-based materials.

Mitochondria-targeted tri-triphenylphosphonium substituted meso-tetra(4-carboxyphenyl)porphyrin(TCPP) by conjugation with folic acid and graphene oxide for improved photodynamic therapy

2019 ◽  
Vol 23 (09) ◽  
pp. 1028-1040
Author(s):  
Chen Yang ◽  
Hongyue Zhang ◽  
Zhiqiang Wang ◽  
Xiaodan Wu ◽  
Yingxue Jin
Keyword(s):  
Graphene Oxide ◽  
Photodynamic Therapy ◽  
Folic Acid ◽  
Apoptotic Cell ◽  
Morphological Changes ◽  
Type I ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Photodynamic Activity ◽  
Yield Formula

Mitochondria are extensively researched as target sites to maximize photodynamic therapy (PDT) effects because they play crucial roles in metabolism. Here, a mitochondria targeting PDT agent, tri-triphenylphosphonium substituted meso-tetra(4-carboxyphenyl)porphyrin (TCPP-TPP) is prepared for the first time. Considering that many porphyrin derivatives are quick to aggregate, thereby reducing the PDT effect, our photosensitizer (PS) was loaded on a folic acid (FA) decorated graphene oxide (GO) nanosystem, called GF@TCPP-TPP, by electrostatic and [Formula: see text]–[Formula: see text] stacking or hydrophobic cooperative interactions, to improve the transportation of photosensitizers and enhance the therapeutic effect. Herein, we have performed a detailed study of photodynamic activity of GF@TCPP-TPP nanocomposites and evaluated their potential as a photosensitizer in PDT. An MTT assay showed that GF@TCPP-TPP inhibited HeLa cells in a concentration-dependent manner under light (650 ± 10 nm, 5 mW [Formula: see text] and 10 min), and presented remarkably improved PDT efficiency (IC[Formula: see text] g [Formula: see text] mL[Formula: see text] of equivalent TCPP-TPP) over free TCPP (IC[Formula: see text] after irradiation. Furthermore, our research indicated that Type I mechanisms (the generation of hydroxyl radicals) play a predominant role in the GF@TCPP-TPP induced PDT process. This coincides with the low singlet oxygen (1O[Formula: see text] quantum yield ([Formula: see text] [Formula: see text] 33.6%) in a DMF solution. Moreover, cell morphological changes after GF@TCPP-TPP PDT further demonstrated that GF@TCPP-TPP could induce damage and apoptotic cell death efficiently. In particular, precise delivery of photosensitizers to mitochondria was proven by organelle localization.

scholarly journals Effects of silver-graphene oxide on seed germination and early growth of crop species

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8387
Author(s):  
Min-Ji Kim ◽  
Woong Kim ◽  
Haegeun Chung
Keyword(s):  
Graphene Oxide ◽  
Seed Germination ◽  
Antimicrobial Agents ◽  
Germination Rate ◽  
Early Growth ◽  
Trophic Levels ◽  
Dependent Manner ◽  
Crop Species ◽  
Concentration Dependent Manner ◽  
The Impact

Due to its excellent material properties, silver-graphene oxide (Ag-GO) is being studied for diverse applications, such as antimicrobial agents, catalysts and absorbents. Such use of Ag-GO may lead to its release into terrestrial ecosystems, but little is known about the impact of Ag-GO on plants. In the present study, we determined the effects of Ag-GO on seed germination and early growth of crop species by analyzing the germination rate, growth of roots and shoots, hydrogen peroxide (H2O2) accumulation, and the uptake of Ag in alfalfa, radish and cucumber treated with 0.2–1.6 mg mL−1 of Ag-GO. Ag-GO treatment increased the shoot growth of radish at 0.2–1.6 mg mL−1 but decreased that of cucumber at 0.8 mg mL−1. In addition, Ag-GO enhanced the root elongation of radish at 0.2 mg mL−1 but inhibited that of alfalfa at 0.2, 0.8 and 1.6 mg mL−1. Ag-GO treatment induced H2O2 production in alfalfa, radish and cucumber in a concentration-dependent manner. Larger amounts of Ag accumulated in the seedlings as the concentration of Ag-GO increased, and such accumulation suggests that Ag may be transferred to higher trophic levels when plants are exposed to Ag-GO in ecosystems. Our study can, thus, serve as an important basis for setting guidelines for the release of nanomaterials into the environment.

The Anti-Atherogenic Properties of Sesamin are Mediated via Improved Macrophage Cholesterol Efflux Through PPARγ1-LXRα and MAPK Signaling

2014 ◽  
Vol 84 (1-2) ◽  
pp. 79-91 ◽  
Author(s):  
Amin F. Majdalawieh ◽  
Hyo-Sung Ro
Keyword(s):  
Cholesterol Efflux ◽  
Transcriptional Activity ◽  
Molecular Mechanisms ◽  
Foam Cell ◽  
Mapk Signaling ◽  
Luciferase Reporter ◽  
Foam Cell Formation ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Macrophage Cholesterol Efflux

Background: Foam cell formation resulting from disrupted macrophage cholesterol efflux, which is triggered by PPARγ1 and LXRα, is a hallmark of atherosclerosis. Sesamin and sesame oil exert anti-atherogenic effects in vivo. However, the exact molecular mechanisms underlying such effects are not fully understood. Aim: This study examines the potential effects of sesamin (0, 25, 50, 75, 100 μM) on PPARγ1 and LXRα expression and transcriptional activity as well as macrophage cholesterol efflux. Methods: PPARγ1 and LXRα expression and transcriptional activity are assessed by luciferase reporter assays. Macrophage cholesterol efflux is evaluated by ApoAI-specific cholesterol efflux assays. Results: The 50 μM, 75 μM, and 100 μM concentrations of sesamin up-regulated the expression of PPARγ1 (p< 0.001, p < 0.001, p < 0.001, respectively) and LXRα (p = 0.002, p < 0.001, p < 0.001, respectively) in a concentration-dependent manner. Moreover, 75 μM and 100 μM concentrations of sesamin led to 5.2-fold (p < 0.001) and 6.0-fold (p<0.001) increases in PPAR transcriptional activity and 3.9-fold (p< 0.001) and 4.2-fold (p < 0.001) increases in LXR transcriptional activity, respectively, in a concentration- and time-dependent manner via MAPK signaling. Consistently, 50 μM, 75 μM, and 100 μM concentrations of sesamin improved macrophage cholesterol efflux by 2.7-fold (p < 0.001), 4.2-fold (p < 0.001), and 4.2-fold (p < 0.001), respectively, via MAPK signaling. Conclusion: Our findings shed light on the molecular mechanism(s) underlying sesamin’s anti-atherogenic effects, which seem to be due, at least in part, to its ability to up-regulate PPARγ1 and LXRα expression and transcriptional activity, improving macrophage cholesterol efflux. We anticipate that sesamin may be used as a therapeutic agent for treating atherosclerosis.

Neutrophil Elastase Potentiates Cathepsin G-lnduced Platelet Activation

1992 ◽  
Vol 68 (05) ◽  
pp. 570-576 ◽  
Author(s):  
Mary A Selak
Keyword(s):  
Neutrophil Elastase ◽  
Cell Activation ◽  
Thromboxane A2 ◽  
Creatine Phosphate ◽  
Dense Granule ◽  
Cathepsin G ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Low Concentrations ◽  
High Concentrations

SummaryWe have previously demonstrated that human neutrophil cathepsin G is a strong platelet agonist that binds to a specific receptor. This work describes the effect of neutrophil elastase on cathepsin G-induced platelet responses. While platelets were not activated by high concentrations of neutrophil elastase by itself, elastase enhanced aggregation, secretion and calcium mobilization induced by low concentrations of cathepsin G. Platelet aggregation and secretion were potentiated in a concentration-dependent manner by neutrophil elastase with maximal responses observable at 200 nM. Enhancement was observed when elastase was preincubated with platelets for time intervals of 10–60 s prior to addition of a low concentration of cathepsin G and required catalytically-active elastase since phenylmethanesulphonyl fluoride-inhibited enzyme failed to potentiate cell activation. Neutrophil elastase potentiation of platelet responses induced by low concentrations of cathepsin G was markedly inhibited by creatine phosphate/creatine phosphokinase and/or indomethacin, indicating that the synergism between elastase and cathepsin G required the participation of ADP and thromboxane A2. On the other hand, platelet responses were not attenuated by the PAF antagonist BN 52021, signifying that PAF-acether did not play a role in elastase potentiation. At higher concentrations porcine pancreatic elastase exhibits similar effects to neutrophil elastase, demonstrating that the effect of elastase was not unique to the neutrophil protease. While neutrophil elastase failed to alter the ability of cathepsin G to hydrolyze a synthetic chromogenic substrate, preincubation of platelets with elastase increased the apparent affinity of cathepsin G binding to platelets. In contrast to their effect on cathepsin G-induced platelet responses, neither neutrophil nor pancreatic elasatse potentiated aggregation or dense granule release initiated by ADP, PAF-acether, arachidonic acid or U46619, a thromboxane A2 mimetic. Moreover, unlike its effect on cathepsin G, neutrophil elastase inhibited thrombin-induced responses. The current observations demonstrate that elastase can potentiate platelet responses mediated by low concentrations of cathepsin G, suggesting that both enzymes may function synergistically to activate platelets under conditions where neutrophil degranulation occurs.

Trimucytin: A Collagen-Like Aggregating Inducer Isolated from Trimeresurus mucrosquamatus Snake Venom

1993 ◽  
Vol 69 (03) ◽  
pp. 286-292 ◽  
Author(s):  
Che-Ming Teng ◽  
Feng-Nien Ko ◽  
Inn-Ho Tsai ◽  
Man-Ling Hung ◽  
Tur-Fu Huang
Keyword(s):  
Platelet Aggregation ◽  
Snake Venom ◽  
Inositol Phosphate ◽  
Shape Change ◽  
Platelet Activating Factor ◽  
Atp Release ◽  
Platelet Membrane ◽  
Thromboxane B2 ◽  
Dependent Manner ◽  
Concentration Dependent Manner

SummaryTrimucytin is a potent platelet aggregation inducer isolated from Trimeresurus mucrosquamatus snake venom. Similar to collagen, trimucytin has a run of (Gly-Pro-X) repeats at the N-terminal amino acids sequence. It induced platelet aggregation, ATP release and thromboxane formation in rabbit platelets in a concentration-dependent manner. The aggregation was not due to released ADP since it was not suppressed by creatine phosphate/creatine phosphokinase. It was not either due to thromboxane A2 formation because indomethacin and BW755C did not have any effect on the aggregation even thromboxane B2 formation was completely abolished by indomethacin. Platelet-activating factor (PAF) was not involved in the aggregation since a PAF antagonist, kadsurenone, did not affect. However, RGD-containing peptide triflavin inhibited the aggregation, but not the release of ATP, of platelets induced by trimucytin. Indomethacin, mepacrine, prostaglandin E1 and tetracaine inhibited the thromboxane B2 formation of platelets caused by collagen and trimucytin. Forskolin and sodium nitroprusside inhibited both platelet aggregation and ATP release, but not the shape change induced by trimucytin. In quin-2 loaded platelets, the rise of intracellular calcium concentration caused by trimucytin was decreased by 12-O-tetradecanoyl phorbol-13 acetate, imipramine, TMB-8 and indomethacin. In the absence of extracellular calcium, both collagen and trimucytin caused no thromboxane B2 formation, but still induced ATP release which was completely blocked by R 59022. Inositol phosphate formation in platelets was markedly enhanced by trimucytin and collagen. MAB1988, an antibody against platelet membrane glycoprotein Ia, inhibited trimucytinand collagen-induced platelet aggregation and ATP release. However, trimucytin did not replace the binding of 125I-labeled MAB1988 to platelets. Platelets pre-exposed to trimucytin were resistant to the second challenge with trimucytin itself or collagen. It is concluded that trimucytin may activate collagen receptors on platelet membrane, and cause aggregation and release mainly through phospholipase C-phosphoinositide pathway.

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