Insights into the exfoliation mechanism of pyrene-assisted liquid phase exfoliation of graphene from lateral size-thickness characterisation

Read, Oliver; Shin, Yuyoung; Hu, Chenxia; Zarattini, Marco; Boyes, Matthew; Just‐Baringo, Xavier; Panigrahi, Adyasha; Larrosa, Igor; Casiraghi, Cinzia

doi:10.1016/j.carbon.2021.09.075

Cited by 14 publications

(31 citation statements)

References 24 publications

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“…Hence, the lateral size measured by AFM is ≈40 nm for MoS 2 and ≈50 nm for WS 2 , while the average thickness is between 4 and 7 nm. Assuming a thickness of 1–1.5 nm for a single layer, and taking into account the adsorbed stabilizer on both sides of the nano‐sheet, [ 19 ] the average number of layers is between 3 and 7. The use of endotoxin‐free test materials is a prerequisite for any study using immune‐competent cells.…”

Section: Resultsmentioning

confidence: 99%

“…The TMDs were prepared using a pyrene‐assisted exfoliation method. [ 19 ] However, while the amount of pyrene adsorbed cannot be easily quantified as there is also a small amount of free pyrene in water, it did not impart any toxicity to the 2D inks. We also documented cellular uptake of the 2D materials as shown by TEM and confirmed by Raman confocal mapping as well as ICP‐MS (for the MoS 2 nano‐sheets).…”

Section: Discussionmentioning

confidence: 99%

“…The nano-sheets were characterized by AFM and Raman spectroscopy as previously reported. [18,19] Sodium molybdate (Na 2 MoO 4 ) (CAS number: 7631-95-0) was purchased from Sigma. The stock solution was prepared at a concentration of 1.280 mg mL −1 (i.e., the equivalent amount of Mo present in 1 mg mL −1 MoS 2 ) in endotoxin-free ultrapure water (EMD Millipore, MA).…”

Section: Methodsmentioning

confidence: 99%

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Two‐Dimensional Transition Metal Dichalcogenides Trigger Trained Immunity in Human Macrophages through Epigenetic and Metabolic Pathways

Peng

Keshavan

Delogu

et al. 2022

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Trained immunity is a recently described phenomenon whereby cells of the innate immune system undergo long‐term epigenetic and/or metabolic reprogramming following a short‐term interaction with microbes or microbial products. Here, it is shown that 2D transition metal dichalcogenides (TMDs) trigger trained immunity in primary human monocyte‐derived macrophages. First, aqueous dispersions of 2D crystal formulations of MoS2 and WS2 are tested, and no cytotoxicity is found despite avid uptake of these materials by macrophages. However, when macrophages are pre‐exposed to TMDs, followed by a resting period, this causes a marked modulation of immune‐specific gene expression upon subsequent challenge with a microbial agent (i.e., bacterial lipopolysaccharides). Specifically, MoS2 triggers trained immunity through an epigenetic pathway insofar as the histone methyltransferase inhibitor methylthioadenosine reverses these effects. Furthermore, MoS2 triggers an elevation of cyclic adenosine monophosphate (cAMP) levels in macrophages and increased glycolysis is also evidenced in cells subjected to MoS2 training, pointing toward a metabolic rewiring of the cells. Importantly, it is observed that MoS2 triggers the upregulation of Mo‐dependent enzymes in macrophages, thus confirming that Mo is bioavailable in these cells. In conclusion, MoS2 is identified as a novel inducer of trained immunity. Thus, TMDs could potentially be harnessed as immunomodulatory agents.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Two‐Dimensional Transition Metal Dichalcogenides Trigger Trained Immunity in Human Macrophages through Epigenetic and Metabolic Pathways

Peng

Keshavan

Delogu

et al. 2022

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“…A Bruker MultiMode 8 atomic force microscope in PFT with ScanAsyst mode, equipped with ScanAsyst-Air cantilevers, was used for all AFM measurements. Aliquots (10 μL) of each fraction were drop cast onto clean, pre-heated (150 °C), Si/SiO 2 wafers (0.5 cm 2 ), washed with DI water and IPA, and then annealed at 250 °C for 2 h. AFM measurements were taken on each sample, following the methodology outlined in detail in ref ( 13 ) and collecting multiple maps capturing over 150 isolated flakes for each fraction. The morphological parameters, lateral size ( L ) and apparent thickness ( T ), were then extracted automatically from the maps using the Gwyddion software, as described in ref ( 13 ).…”

Section: Methodsmentioning

confidence: 99%

“… 16 , 21 However, the exact exfoliation efficiency and dispersion stability strongly depend on the precise structure of the pyrene stabilizer, 14 , 15 , 17 , 18 whereas the size and thickness of obtained flakes are largely unaffected by the type of pyrene derivative. 13 …”

Section: Introductionmentioning

confidence: 99%

Effects of Lateral Size, Thickness, and Stabilizer Concentration on the Cytotoxicity of Defect-Free Graphene Nanosheets: Implications for Biological Applications

Read

Shin

et al. 2022

ACS Appl. Nano Mater.

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In this work, we apply liquid cascade centrifugation to highly concentrated graphene dispersions produced by liquid-phase exfoliation in water with an insoluble bis-pyrene stabilizer to obtain fractions containing nanosheets with different lateral size distributions. The concentration, stability, size, thickness, and the cytotoxicity profile are studied as a function of the initial stabilizer concentration for each fraction. Our results show that there is a critical initial amount of stabilizer (0.4 mg/mL) above which the dispersions show reduced concentration, stability, and biocompatibility, no matter the lateral size of the flakes.

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Wearable Sensors for Breath Monitoring Based on Water‐Based Hexagonal Boron Nitride Inks Made with Supramolecular Functionalization

Chen,

Hu,

et al. 2024

Advanced Materials

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Wearable humidity sensors are attracting strong attention as they allow to continuously monitor in real time important physiological information by enabling activity tracking as well as air quality assessment. Amongst 2‐Dimensional (2D) materials, Graphene Oxide (GO) is very attractive for humidity sensing due to its tuneable surface chemistry, high surface area, processability in water and easy integration onto flexible substrates. However, large hysteresis, low sensitivity and strong cross‐sensitivity issues limit the use of GO in practical applications, where continuous monitoring is preferred. Herein, we demonstrate a wearable and wireless impedance‐based humidity sensor made with pyrene‐functionalized hexagonal boron nitride (h‐BN) nanosheets, which shows enhanced sensitivity towards relative humidity, RH (>1010 Ohms/%RH in the range from 5% to 100%RH), fast response (0.1 ms), no appreciable hysteresis and cross‐sensitivity in the range of 25–60°C. We finally demonstrate that the h‐BN based sensor is able to monitor the whole breathing cycle process of exhaling and inhaling, hence enabling to record in real time the subtlest changes of respiratory signals associated with different daily activities as well as various symptoms of flu, without requiring any direct contact with the individual.This article is protected by copyright. All rights reserved

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Insights into the exfoliation mechanism of pyrene-assisted liquid phase exfoliation of graphene from lateral size-thickness characterisation

Cited by 14 publications

References 24 publications

Two‐Dimensional Transition Metal Dichalcogenides Trigger Trained Immunity in Human Macrophages through Epigenetic and Metabolic Pathways

Two‐Dimensional Transition Metal Dichalcogenides Trigger Trained Immunity in Human Macrophages through Epigenetic and Metabolic Pathways

Effects of Lateral Size, Thickness, and Stabilizer Concentration on the Cytotoxicity of Defect-Free Graphene Nanosheets: Implications for Biological Applications

Wearable Sensors for Breath Monitoring Based on Water‐Based Hexagonal Boron Nitride Inks Made with Supramolecular Functionalization

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