scholarly journals A few-layer graphene/chlorin e6 hybrid nanomaterial and its application in photodynamic therapy against Candida albicans

2020 ◽  
Vol 11 ◽  
pp. 1054-1061
Author(s):  
Selene Acosta ◽  
Carlos Moreno-Aguilar ◽  
Dania Hernández-Sánchez ◽  
Beatriz Morales-Cruzado ◽  
Erick Sarmiento-Gomez ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Fungal Infections ◽  
Chlorin E6 ◽  
Ros Generation ◽  
Photodynamic Treatment ◽  
Hybrid Nanomaterial ◽  
Layer Graphene ◽  
Wide Range ◽  
Red Led ◽  
Few Layer Graphene

The global emergence of multidrug resistance of fungal infections and the decline in the discovery of new antibiotics are increasingly prevalent causes of hospital-acquired infections, among other major challenges in the global health care sector. There is an urgent need to develop noninvasive, nontoxic, and new antinosocomial approaches that work more effectively and faster than current antibiotics. In this work, we report on a biocompatible hybrid nanomaterial composed of few-layer graphene and chlorin e6 (FLG-Ce6) for the photodynamic treatment (PDT) of Candida albicans. We show that the FLG-Ce6 hybrid nanomaterial displays enhanced reactive oxygen species (ROS) generation compared with Ce6. The enhancement is up to 5-fold when irradiated for 15 min at 632 nm with a red light-emitting diode (LED). The viability of C. albicans in the presence of FLG-Ce6 was measured 48 h after photoactivation. An antifungal effect was observed only when the culture/FLG-Ce6 hybrid was exposed to the light source. C. albicans is rendered completely unviable after exposure to ROS generated by the excited FLG-Ce6 hybrid nanomaterial. An increased PDT effect was observed with the FLG-Ce6 hybrid nanomaterial by a significant reduction in the viability of C. albicans, by up to 95%. This is a marked improvement compared to Ce6 without FLG, which reduces the viability of C. albicans to only 10%. The antifungal action of the hybrid nanomaterial can be activated by a synergistic mechanism of energy transfer of the absorbed light from Ce6 to FLG. The novel FLG-Ce6 hybrid nanomaterial in combination with the red LED light irradiation can be used in the development of a wide range of antinosocomial devices and coatings.

scholarly journals Structural Investigation of the Synthesized Few-Layer Graphene from Coal under Microwave

Nanomaterials ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 57
Author(s):  
Faridul Islam ◽  
Arash Tahmasebi ◽  
Behdad Moghtaderi ◽  
Jianglong Yu
Keyword(s):  
Potassium Hydroxide ◽  
Bituminous Coal ◽  
Structural Investigation ◽  
The Other ◽  
Activation Process ◽  
Thin Sheets ◽  
Layer Graphene ◽  
Wide Range ◽  
Few Layer Graphene ◽  
Microwave Heat

This study focused on the structural investigation of few-layer graphene (FLG) synthesis from bituminous coal through a catalytic process under microwave heat treatment (MW). The produced FLG has been examined by Raman spectroscopy, XRD, TEM, and AFM. Coal was activated using the potassium hydroxide activation process. The FLG synthesis processing duration was much faster requiring only 20 min under the microwave radiation. To analyse few-layer graphene samples, we considered the three bands, i.e., D, G, and 2D, of Raman spectra. At 1300 °C, the P10% Fe sample resulted in fewer defects than the other catalyst percentages sample. The catalyst percentages affected the structural change of the FLG composite materials. In addition, the Raman mapping showed that the catalyst loaded sample was homogeneously distributed and indicated a few-layer graphene sheet. In addition, the AFM technique measured the FLG thickness around 4.5 nm. Furthermore, the HRTEM images of the P10% Fe sample contained a unique morphology with 2–7 graphitic layers of graphene thin sheets. This research reported the structural revolution with latent feasibility of FLG synthesis from bituminous coal in a wide range.

scholarly journals Multi-Layer Graphene Oxide in Human Keratinocytes: Time-Dependent Cytotoxicity, Proliferation, and Gene Expression

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 414
Author(s):  
Beatriz Salesa ◽  
Ángel Serrano-Aroca
Keyword(s):  
Graphene Oxide ◽  
Human Keratinocytes ◽  
Control Group ◽  
Hacat Cells ◽  
Layer Graphene ◽  
Wide Range ◽  
Epidermal Growth ◽  
Biomedical Field ◽  
Few Layer Graphene ◽  
Median Effective Concentration

Few-layer graphene oxide (GO) has shown no or very weak cytotoxicity and anti-proliferative effects in a wide range of cell lines, such as glioma cells and human skin HaCaT cells at concentrations up to 100 µg/mL. However, as multi-layer GO has hardly been explored in the biomedical field, in this study, this other type of GO was examined in human keratinocyte HaCaT cells treated with different concentrations, ranging from 0.01 to 150 µg/mL, for different periods of time (3, 12, and 24 h). The results revealed a time–concentration dependence with two non-cytotoxic concentrations (0.01 and 0.05 µg/mL) and a median effective concentration value of 4.087 µg/mL at 24 h GO exposure. Contrary to what has previously been reported for few-layer GO, cell proliferation of the HaCaT cells in contact with the multi-layer GO at 0.01 μg/mL showed identical proliferative activity to an epidermal growth factor (1.6-fold greater than the control group) after 96 h. The effects of the multi-layer GO on the expression of 13 genes (SOD1, CAT, MMP1, TGFB1, GPX1, FN1, HAS2, LAMB1, LUM, CDH1, COL4A1, FBN, and VCAN) at non-cytotoxic concentrations of GO in the HaCaT cells were analyzed after 24 h. The lowest non-cytotoxic GO concentration was able to upregulate the CAT, TGFB1, FN1, and CDH1 genes, which confirms multi-layer GO’s great potential in the biomedical field.

One-step synthesis and deposition of few-layer graphene via facile, dry ball-free milling

MRS Advances ◽  
2017 ◽  
Vol 2 (15) ◽  
pp. 847-856 ◽  
Author(s):  
Abdul Hai Alami ◽  
Kamilia Aokal ◽  
Mhd Adel Assad ◽  
Di Zhang ◽  
Hussain Alawadhi ◽  
...  
Keyword(s):  
Low Cost ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Hydrophobic Surface ◽  
Graphite Powder ◽  
High Energy ◽  
Layer Graphene ◽  
Wide Range ◽  
One Step ◽  
Few Layer Graphene

ABSTRACTGraphene is a 2-D carbon material showing considerable prominence in a wide range of optoelectronics, energy storage, thermal and mechanical applications. However, due to its unique features which are typically associated with difficulty in handling (ultra-thin thickness and hydrophobic surface, to name a few), synthesis and subsequent deposition processes are thus critical to the material properties of the prepared graphene films. While existing synthesis approaches such as chemical vapor deposition and epitaxial growth can grow graphene with high degree of order, the costly high temperature and/or high vacuum process prohibit the widespread usage, and the subsequent graphene transfer from the growth substrates for deposition proves to be challenging. Herein, a low-cost one-step synthesis and deposition approach for preparing few-layer graphene (FLG) on flexible copper substrates based on dry ball-free milling of graphite powder is proposed. Different from previous reports, copper substrates are inserted into the milling crucible, thus accomplishing simultaneous synthesis and deposition of FLG and eliminating further deposition step. Furthermore, while all previously reported high energy milling processes involve using balls of various sizes, we adopt a ball-free milling process relying only on centrifugal forces, which significantly reduces the surface damage of the deposition substrates. Sample characterization indicates that the process yields FLG deposited uniformly across all tested specimens. Consequently, this work takes graphene synthesis and deposition a step closer to full automation with simple and low-cost process.

scholarly journals Synthesis of a nitrogen rich (2D–1D) hybrid carbon nanomaterial using a MnO2 nanorod template for high performance Li-ion battery applications

2015 ◽  
Vol 3 (13) ◽  
pp. 6810-6818 ◽  
Author(s):  
B. P. Vinayan ◽  
Nele I. Schwarzburger ◽  
Maximilian Fichtner
Keyword(s):  
High Performance ◽  
Li Ion Battery ◽  
Carbon Nanomaterial ◽  
Hybrid Nanomaterial ◽  
Layer Graphene ◽  
Novel Approach ◽  
Li Ion ◽  
Few Layer Graphene ◽  
Hybrid Carbon ◽  
Battery Anode

A novel approach to synthesize a nitrogen rich few layer graphene–carbon nanotube hybrid nanomaterial for high performance Li ion battery anode electrodes.

scholarly journals Pell-Shear-Exfoliation of few-layer graphene nanoflakes as an electrode in supercapacitors

2018 ◽  
Vol 6 (1) ◽  
pp. 1-10
Author(s):  
Ibrahem Aziz Mohammed
Keyword(s):  
Thin Films ◽  
Low Cost ◽  
Spray Coating ◽  
High Specific Capacitance ◽  
Optical Transmittance ◽  
High Quality ◽  
Layer Graphene ◽  
Graphene Nanoflakes ◽  
Wide Range ◽  
Few Layer Graphene

Introduction: The graphene has received a great attention because of its extraordinary characteristics of high carrier mobility, excellent thermal conductivity, high optical transmittance, and superior mechanical strength. Developing a simple methods with the property of producing large quantities of high-quality graphene have become essential for electronics, optoelectronics, composite materials, and energy-storage applications. Materials and Methods: In this study, the simple one step and efficient method of grinding was used to produce few-layers graphene nanoflakes from graphite. Different microscopic (TEM, SEM, and AFM) and spectroscopics (XRD, XPS, and Raman) charactrization tools were used to test the quality of the resultant graphene nanoflakes. Results: The produced nanoflakes showed no traces of oxidation due to the grinding process. In addition, the applicability of the obtained nanoflakes as potential supercapacitor electrodes was investigated. For that purpose, thin films of the few-layer graphene nanoflakes were developed using spray coating technique. In terms of both transparency and conductivity, the prepared films showed equivalent properties compared to those prepared by more complex methods. The electrochemical properties of the prepared electrodes showed high specific capacitance of 86 F g_1 at 10 A g_1 with excellent stability. The electrodes sustained their original capacity for more than 7000 cycles and started reducing to 72 F g−1 after 10000 cycles. Conclussions: The method provides a simple, efficient, versatile, and eco-friendly approach to low-cost mass production of high-quality graphene few-layers. The electrochemical stability and flexibility of the developed thin films indicated that the films could be used as electrodes in a wide range of electronic applications.

scholarly journals Multi-Layer Graphene Oxide in Human Keratinocytes: Time-Dependent Cytotoxicity, Proliferation, and Gene Expression

2021 ◽  
Author(s):  
Beatriz Salesa ◽  
Ángel Serrano-Aroca
Keyword(s):  
Graphene Oxide ◽  
Human Keratinocytes ◽  
Control Group ◽  
Hacat Cells ◽  
Layer Graphene ◽  
Wide Range ◽  
Epidermal Growth ◽  
Biomedical Field ◽  
Few Layer Graphene ◽  
Median Effective Concentration

Few-layer graphene oxide (GO) has shown none or very weak cytotoxicity and anti-proliferative effects in a wide range of cell lines such as glyoma cells and human skin HaCaT cells, in concentrations up to 100 µg/mL However, multi-layer GO has been hardly explored in the biomedical field. Thus, multi-layer GO was examined here in human keratinocyte HaCaT cells treated with different concentrations ranging from 0.01 to 150 µg/mL during different periods of times (3, 12 and 24 hours). The results of this study showed a time-concentration dependence with two non-cytotoxic concentrations (0.01 and 0.05 µg/mL) and a median effective concentration value of 4.087 µg/mL at 24 hours of GO exposure. Contrary to what has been reported for few-layer GO, cell proliferation of the HaCaT cells in contact with the multi-layer GO at 0.01 μg/mL showed identical proliferative activity compared to an epidermal growth factor (1.6-fold greater than the control group) after 96 hours. The effects of the multi-layer GO on the expression of 13 genes (SOD1, CAT, MMP1, TGFB1, GPX1, FN1, HAS2, LAMB1, LUM, CDH1, COL4A1, FBN and VCAN) at the non-cytotoxic concentrations of GO in the HaCaT cells were analyzed after 24 hours. Thus, the lowest non-cytotoxic GO concentration was able to up-regulate the CAT, TGFB1, FN1 and CDH1 genes, which confirms the great potential of multi-layer GO in the biomedical field.

scholarly journals Flavones, Flavonols, and Glycosylated Derivatives—Impact on Candida albicans Growth and Virulence, Expression of CDR1 and ERG11, Cytotoxicity

2020 ◽  
Vol 14 (1) ◽  
pp. 27
Author(s):  
Marija Ivanov ◽  
Abhilash Kannan ◽  
Dejan S. Stojković ◽  
Jasmina Glamočlija ◽  
Ricardo C. Calhelha ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Fungal Infections ◽  
Ergosterol Biosynthesis ◽  
Fungal Virulence ◽  
Wide Range ◽  
Genes Encoding ◽  
Increasing Demand ◽  
Hyphal Formation ◽  
Further Development

Due to the high incidence of fungal infections worldwide, there is an increasing demand for the development of novel therapeutic approaches. A wide range of natural products has been extensively studied, with considerable focus on flavonoids. The antifungal capacity of selected flavones (luteolin, apigenin), flavonols (quercetin), and their glycosylated derivatives (quercitrin, isoquercitrin, rutin, and apigetrin) along with their impact on genes encoding efflux pumps (CDR1) and ergosterol biosynthesis enzyme (ERG11) has been the subject of this study. Cytotoxicity of flavonoids towards primary liver cells has also been addressed. Luteolin, quercitrin, isoquercitrin, and rutin inhibited growth of Candida albicans with the minimal inhibitory concentration of 37.5 µg/mL. The application of isoquercitrin has reduced C. albicans biofilm establishing capacities for 76%, and hyphal formation by yeast. In vitro treatment with apigenin, apigetrin, and quercitrin has downregulated CDR1. Contrary to rutin and apigenin, isoquercitrin has upregulated ERG11. Except apigetrin and quercitrin (90 µg/mL and 73 µg/mL, respectively inhibited 50% of the net cell growth), the examined flavonoids did not exhibit cytotoxicity. The reduction of both fungal virulence and expression of antifungal resistance-linked genes was the most pronounced for apigenin and apigetrin; these results indicate flavonoids’ indispensable capacity for further development as part of an anticandidal therapy or prevention strategy.

Ultrastructural Changes of Candida albicans Species Induced by the Presence of Sodium Diclofenac

2017 ◽  
Vol 68 (11) ◽  
pp. 2566-2569 ◽  
Author(s):  
Elena Rusu ◽  
Ionela Sarbu ◽  
Magdalena Mitache ◽  
Horatiu Moldovan ◽  
Carmen Ioana Biris ◽  
...  
Keyword(s):  
Candida Albicans ◽  
High Frequency ◽  
Fungal Infections ◽  
Diagnostic Methods ◽  
Ultrastructural Changes ◽  
Frequency Of Occurrence ◽  
Medical Treatments ◽  
Sodium Diclofenac ◽  
Cell Wall Disruption ◽  
Candidiasis Treatment

The high frequency of occurrence of candidiasis as well as high mortality of patients with immunosuppression cause a tendency toward better understanding of Candida albicans species virulence factors and developing sensitive and specific diagnostic methods, and appropriate strategies of candidiasis treatment. In recent decades the incidence of fungal infections has alarming increases because of advanced medical treatments. In this study was analyzed possible ultrastructural changes of the species C. albicans cells following treatment with sodium diclofenac at various concentrations. Following treatment of C. albicans cells with sodium diclofenac 1 mM and 2 mM changes in the plasmalemma can be noticed, changes in the density of cell wall, disruption and necrotic appearance of the cytoplasm.

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