Idiopathic pulmonary fibrosis (IPF) pathogenesis involves multiple pathways, and combined antifibrotic therapy is needed for future IPF therapy. Inhaled interferon-γ (IFN-γ) was recently shown to be safe and without systemic effects in patients with IPF.To examine the in vitro effects of individual and combined treatment with IFN-γ and pirfenidone (PFD) on normal and IPF fibroblast activation and extracellular matrix remodeling after TGF-β1 and PDGF-BB stimulation.IPF and normal human lung fibroblasts (NHLF) were treated with IFN-γ, PFD or a combination of both drugs in the presence of either TGF-β1 or PDGF-BB. The effects of TGF-β1 and PDGF-BB treatment on cell viability, proliferation, differentiation and migration were examined. The expression of collagen 1, matrix metalloproteinases (MMPs) and tissue inhibitors of MMP (TIMPs) was analyzed using qPCR, Western blotting and gelatin zymography. Total collagen content in conditioned media was also measured using a Sircol assay.Compared to that of PFD, the effect of IFN-γ in downregulating normal and IPF lung fibroblast differentiation to myofibroblasts in response to TGF-β1 was more potent. Importantly, the combination of IFN-γ and PFD had a possibly synergistic/additive effect in inhibiting the TGF-β1- and PDGF-BB-induced proliferation, migration and differentiation of normal and IPF lung fibroblasts. Furthermore, both drugs reversed TGF-β1-induced effects on MMP-1, − 2, − 3, − 7, and − 9, while only PFD promoted TIMP-1 and-2 expression and release.Our findings demonstrate that the antifibrotic effects of IFN-γ and PFD on normal and IPF lung fibroblasts are different and complementary. Combination therapy with inhaled IFN-γ and PFD in IPF is promising and should be further explored in IPF clinical trials. Idiopathic pulmonary fibrosis (IPF) is the most common form of idiopathic interstitial pneumonia, and patients with IPF exhibit poor survival and have limited therapeutic options , 2. DysrGiven the complex pathogenesis of IPF leading to lung fibrosis, which involves multiple coactivated pathways, combination therapy may be a rational treatment approach in IPF patients. Treatment of IPF with pirfenidone or nintedanib does not stop ongoing fibrosis and is limited to patients with only mild to moderate disease . PirfeniInterferon-γ (IFN-γ) is a pleiotropic cytokine with antiviral, antibacterial, antitumor, and pro-inflammatory properties that also has antifibrotic activities . BecauseThe present study aims to examine the in vitro effect of individual and combined treatment with IFN-γ and PFD on the activation of NHLF and IPF fibroblasts and ECM remodeling after TGF-β1 and PDGF-BB stimulation., IFN-γ in combination with PFD has a possibly synergistic/additive effect by inhibiting the activation and differentiation of NHLF and IPF lung fibroblasts possibly by altering the balance of MMPs and TIMPs.Here, we show that IFN-γ treatment attenuates normal and IPF fibroblast differentiation to the myofibroblast phenotype in vitro more effectively than PFD, illuminating a potential therapeutic strategy. FurthermoreA normal human lung fibroblast (NHLF) cell line (cat # CC2512) was purchased from Lonza . We used 3 different batches of NHLF cells collected from 3 different donors as follows: Batch # 0000343490 was collected from a 24-year-old female; batch # 0000369145 was collected from a 43-year-old male and batch # 0000608197 was collected from a 67-year-old male. NHLFs were cultured in fibroblast growth medium (FGM-2) (Lonza), and cells at passage 3 to 7 were used for all experiments. Three human IPF lung fibroblast cell lines (CCL-134 and CCL-191) were purchased from American Type Culture Collection (ATCC) , and IPF lung fibroblasts (cat # CC-7231) purchased from Lonza at passage 2 to 5 were used for all experiments. IPF lung fibroblasts from ATCC were cultured in F12K medium, while those from Lonza were cultured in FGM-2 (Lonza). Early passages of IPF fibroblasts were used in this study as IPF-derived fibroblasts are known to display morphological features of replicative senescence even at early passage, unlike age-matched control fibroblasts at the same passage , 31. Hum2, followed by starvation for 2 h in serum-free medium (SFM). The lung fibroblasts were subsequently treated with or without TGF-β1 (2.5 ng/ml) or PDGF-BB (20 ng/ml) with either IFN-γ (10–40 ng/ml), PFD (100–500 μg/ml) or both IFN-γ /PFD in serum-free media supplemented with 0.1% BSA to provide a protein source to support cell growth. We did not use serum in culture media because it has a mitogenic effect on fibroblasts. Previous reports showed that lung fibroblasts survived in serum-free medium and sustain an increase in cell number after 2 days of starvation in SFM secondary to the autocrine secretion of various mediators, including PDGF, that could influence proliferation and the synthetic activity of fibroblasts -thymidine incorporation as per the Promega and our previous laboratory experience [NHLFs and IPF fibroblasts  seeded on 24-well plates were grown overnight in serum-containing medium. On the following day, cells were switched to SFM supplemented with 0.1% BSA and treated with PDGF-BB (20 ng/ml) and different concentrations of IFN-γ and PFD for 1 or 3 days. At the end of the experiments, the cells were detached from the plate using BD cell detachment solution . The cell number was counted by a Cellometer™ Auto 2000 cell counter . Cell viability was determined manually by counting cells after trypan blue staining using a Neubauer hematocytometer and an automated Cellometer.NHLFs and IPF fibroblasts (5 × 105 cells in 100 μl of DMEM containing 0.1% BSA and either IFN-γ (10–40 ng/ml), PFD (100–500 μg/ml) or both IFN-γ /PFD. PDGF-BB (20 ng/ml) was added to the lower chambers. The Transwells were incubated for 24 h. at 37 °C in a CO2 incubator. The number of cells that migrated to the lower surface of the membrane was counted under 200× magnification. Ten random high-power fields were counted per sample. Each group was run in triplicate.NHLFs and IPF fibroblasts were assessed for their ability to migrate in the presence PDGF-BB (20 ng/ml) using a modified Boyden chamber assay. The migration assays were performed with 24-well tissue culture Transwell plates  composed of polycarbonate membranes with 8 μm pores. Lung fibroblasts were seeded on the upper chambers of the Transwells at 1 × 10Confluent serum-deprived fibroblasts were stimulated with TGF-β1 (2.5 ng/ml) and incubated in the presence of either IFN-γ, PFD or both for the indicated time periods. Soluble collagen secretion (collagens type I to V) in the conditioned media was determined using a Sircol™ Assay kit  according to the manufacturer’s instructions.The protein concentrations of the cell lysates were determined by BCA assay. Equal amounts of proteins (20 μg) from cell lysates were resolved by 8–16% SDS-PAGE and transferred onto a nitrocellulose membrane . After blocking with 5% milk, the membranes were incubated with primary antibodies overnight at 4 °C followed by incubation with horseradish peroxidase-conjugated secondary antibodies and detection by use of an enhanced chemiluminescence detection system . Primary antibodies included mouse monoclonal anti-α-SMA ; rabbit polyclonal anti-MMP-1, MMP-3 and MMP-7 ; and β-tubulin . Bands were digitalized, and their densities were quantified using image analysis software. The results are expressed as a ratio of band density to total β-tubulin density.Gelatin zymography of conditioned media was performed as described previously . Briefly: COL1A1, ACTA2, MMP1, MMP3, MMP7, MMP8, MMP9, TIMP1, TIMP2 and YWHAZ (TaqMan™ Gene Expression Assay (FAM), Thermo-Fisher Scientific, Waltham, MA USA). qPCR was performed on an ABI Prism 7000 sequence detection system, and mRNA levels for each gene were analyzed with ABI Prism 7000 software . Relative quantification of each target gene was performed using the comparative CT (2-∆∆CT) method with YWHAZ  used as a housekeeping gene for the normalization of mRNA expression levels as reported in previous studies [-ΔΔCT (mean fold change) using Graph Pad prism software.RNAs were extracted from IPF and normal lung fibroblasts 24 h and 72 h after TGF-β1 treatment with either IFN-γ, PFD or both using RNeasy mini kits  according to the manufacturer’s instructions. The RNAs were reverse transcribed into cDNAs, which were subjected to qPCR analyses using primer pairs specific to each of the following genes studies , 37. Datp < 0.05.All results are reported as the mean ± SEM. Data from image analysis are shown as representative immunoblots and as the means ± SEMs after densitometric image analysis. A paired t-test was used for statistical analysis between 2 groups, and ordinary one-way ANOVA followed by Tukey’s multiple comparisons test using GraphPad Prism 8 software were used for comparisons between groups to assess differences among conditions. Significance was indicated when *For in vitro experiments, we selected a range of IFN-γ (10–40 ng/mL) and PFD (100–500 μg/mL) concentrations similar to those used in published studies –42. NHLFp = 0.0002, Fig. p = 0.014 Fig. Next, NHLF and IPF fibroblast cell proliferation was examined using a Cell Titer 96® Non-Radioactive Proliferation Assay  or automated cell counting. As shown in Fig. p < 0.01, Fig. p > 0.05, Fig. When 20 mg/ml PDGF-BB was used as a mitogen, as shown in Fig. p < 0.001, Fig. Both IFN-γ (10–40 ng/ml) and PFD (300–500 μg/ml) inhibited the migration of NHLFs and IPF fibroblasts in a dose-dependent manner in the presence of PDGF-BB (20 ng/ml)  and their inhibitors (TIMPs) have been implicated in the pathogenesis of IPF. TGF-β1 is known to tivation , 59–61. ion Fig. b. MMP-2 on Figs. a. MMP-3 gs. MMP3 , MMP2 anand MMP9 , 68. Othroblasts .-induced inhibition of MMP7 and MMP1 expression. MMP-1 is significantly overexpressed in IPF lungs [against IPF fibroblasts [Both IFN-γ and PFD reversed the TGF-β1PF lungs  and was roblasts . Moreoveroblasts , 69. In roblasts .Interestingly, only PFD treatment increased TIMP1 and TIMP2 expression and release in normal and IPF fibroblasts (Figs. 1 and -2 are highly induced during fibrosis in a number of animal models of lung fibrosis [TIMP1−/−mice have pulmonary fibrotic responses to bleomycin similar to those of wild-type mice [TIMP1−/− mice, suggesting that TIMP-1 plays a key role in restricting inflammation following lung injury [TIMP1−/− mice had significantly increased injury, inflammation, and fibrosis following carbon tetrachloride-induced liver injury compared to wild-type mice [ts Figs.  and 7. Tfibrosis –73. In ffibrosis –77. Althype mice , inflammg injury . TIMP-1 ype mice .provide evidence that IFN-γ and PFD have different and potentially complementary antifibrotic effects on NHLFs and IPF lung fibroblasts. IFN-γ exerts its antifibrotic effect by inhibiting fibroblast differentiation to myofibroblasts and ultimately inhibits collagen and α-SMA expression possibly via counteracting the effects of TGF-β1. In contrast, PFD exerts its antifibrotic effect on lung fibroblasts possibly by reversing the effect of TGF-β1 on MMPs/TIMPs. IFN-γ and PFD in combination have a possibly synergistic effect on lung fibroblast activation and differentiation to myofibroblasts. Unfortunately, this in vitro study is still far from able to simulate complex situations such as the interactions between cell types and their compensatory mechanisms. The present findings support further investigation of the mechanisms underlying the antifibrotic effect of combined IFN-γ and PFD therapy in an in vivo model of lung fibrosis.Taken together, the data presented here fibroblasts. Combination therapy with IFN-γ and PFD may be a new and promising approach to the treatment of IPF and should be further explored in clinical trials.The present study demonstrates that combined IFN-γ and PFD treatment has possibly synergistic antifibrotic effects on NHLFs and IPF


Plasmons, collective oscillations of electron systems, can efficiently couple light and electric current, and thus can be used to create sub-wavelength photodetectors, radiation mixers, and on-chip spectrometers. Despite considerable effort, it has proven challenging to implement plasmonic devices operating at terahertz frequencies. The material capable to meet this challenge is graphene as it supports long-lived electrically tunable plasmons. Here we demonstrate plasmon-assisted resonant detection of terahertz radiation by antenna-coupled graphene transistors that act as both plasmonic Fabry-Perot cavities and rectifying elements. By varying the plasmon velocity using gate voltage, we tune our detectors between multiple resonant modes and exploit this functionality to measure plasmon wavelength and lifetime in bilayer graphene as well as to probe collective modes in its moiré minibands. Our devices offer a convenient tool for further plasmonic research that is often exceedingly difficult under non-ambient conditions (e.g. cryogenic temperatures) and promise a viable route for various photonic applications. Plasmons confined in field effect transistors were long envisioned for resonant detection of light at THz frequencies, however realization of such photodetectors has proven challenging. Here, the authors fabricate antenna-coupled graphene transistors which exhibit resonant photoresponse to incident radiation and use them to study plasmons in graphene and its moiré superlattices. Among the variety of available detection principles2, one elegant proposal has always stood out and remained intriguing for more than two decades. The idea is to compress incident radiation into highly-confined two-dimensional plasmons propagating in the field effect transistor (FET) channel and to rectify the induced ac potential using the same device3. The FET channel, in this case, acts as a tunable plasmonic cavity with a set of resonant frequencies defined by its length and the density of charge carriers. The implementation of such resonant devices has promised on-chip selective sensing, spectroscopy, mixing, and modulation of THz fields below the classical diffraction limit3. However, despite decades-long experimental efforts, the excitation of long-lived plasma oscillations in conventional FETs has proven challenging9 and little evidence of resonant THz detection has been found so far14.Selective detection and spectroscopy of THz fields is a challenging task in modern optoelectronics offering a wide range of applications: from security and medical inspection to radio astronomy and wireless communications22 and attracted a great deal of attention as a platform for plasmonic radiation detectors23. With lowering the operation frequency down to the THz domain, the resonant excitation of plasmons becomes exceedingly difficult and can only be achieved if the momentum relaxation rate is below the plasmon frequency, which, in turn, requires ultra-high electron mobility. For this reason, in all graphene-based far-field THz detectors reported so far, the plasma waves—if any—were overdamped, and the devices exhibited only a broadband (non-resonant) photoresponse25. As a result, numerous applications relying on resonant plasmon excitation (see e.g. refs. 29) remain experimentally yet unrealized.Graphene has recently demonstrated great promise for mid- and far-infrared plasmonics22. Antenna-mediated coupling of such FETs to free-space radiation results in the emergence of dc photovoltage that peaks when the channel hosts an odd number of plasmon quarter-wavelengths. Exploiting the gate-tunability of plasmon velocity, we switch our detectors between more than 10 resonant modes, and use this functionality to measure plasmon wavelength and lifetime. Thanks to the far-field radiation coupling, our compact devices offer a convenient tool for studies of plasmons in two-dimensional electron systems under non-ambient conditions (e.g. cryogenic environment and high magnetic fields) where other techniques may be arduous. As an example, we apply our approach to probe plasmons in graphene/hBN superlattices and unveil collective modes of charge carriers in moiré minibands.In this work, we demonstrate this long-sought resonant regime using FETs based on high-quality van der Waals heterostructures. In particular, we employ graphene encapsulated between hexagonal boron nitride (hBN) crystals which have been shown to provide the cleanest environment for long-lived graphene plasmons8 requirements, we fabricated proof-of-concept detectors using high-mobility bilayer graphene (BLG) FETs. To this end, we first applied a standard dry transfer technique to encapsulate BLG between two relatively thin (d ≈ 80 nm) slabs of hBN30. The heterostructure had side contacts . In good agreement with the previous studies, the Ra(Vg) dependence follows the evolution of the FET-factor Ra increases in magnitude upon approaching the charge neutrality point (NP) where it flips sign because of the change in charge carrier type.We intentionally start the photoresponse measurements at the low end of the sub-THz domain, where the plasma oscillations are overdamped (see below). This allows us to compare the performance of our detectors with previous reportsRa grows with decreasing T  at this T  dependence that, in turn, causes a drastic enhancement of Ra  are observed for the same gate voltage span as in Fig. We have also studied the performance of our detectors at intermediate frequencies and found that the resonant operation of our devices onsets in the middle of the sub-THz domain  is the dimensionless coupling constant and εz is the out-of-plane dielectric permittivity34. We further note that Eq.  for experimentally accessible values of Vg, a feature that allows us to vary s over a wider range and thus switch the detector between multiple modes, as we now proceed to show.We argue that the observed peaks in the photoresponse emerge as a result of plasmon resonance in the FET channel. To this end, we model our FET as a plasmonic Fabry-Perot cavity endowed with a rectifying element. This results in responsivity given byentclass1pt{minimarsrd ≈ −1 (refs. 32). The resonances should therefore occur whenever the real part of the wave number is quantized according tok on L = 6 μm. At large 33. Note that the known non-parabolicity of the BLG spectrum35 resulting in an increase of m at large density n would bend the dependence in Fig. It follows from Eq. , that th−1 refs. 2. The reL = (2k + 1)λp/4, where λp = 2π/q′ is the plasmon wavelength  ranges between 1/50 and 1/150, highlighting the ultra-strong confinement of THz fields enabled by graphene plasmons, matching the record value known in the literature20.The resonant gate-tunable response of our detectors offers a convenient tool to characterize plasmon modes in graphene channels. From Eq.  it follogth Fig. . Using tλp, the resonant responsivity carries information about another valuable characteristic of plasmons, namely, their lifetime, τp. The latter is related to the peak width at half-height δ via  follows that of the FET-factor (black curve) modulated by the plasmon resonances. Note the total number of resonances is smaller due to the shorter FET channel  is high enough to induce interband absorption close to the sNP, which hampers the observation of plasmons in superlattice minibands39. In contrast, our approach relies on the low-energy excitations (2 THz ≈ 8 meV), is applicable at cryogenic temperatures, and, therefore, paves a convenient way for further studies of miniband plasmonics.A striking feature of the superlattice photoresponse is the resonances appearing when the Fermi level is brought close to the sNP  between electron and hole doping indicates rectification at the p–n junction formed in vicinity of the contacts. This rectification usually appears due to the thermoelectric effect arising as a result of non-uniform sample heating and the difference between the Seebeck coefficients in the graphene channel and contact regions40  rectification3 and result in R0 proportional to the sensitivity of the conductivity to the gate voltage variation4, given by the F-factor introduced above  and Z ≈ 74 Ω, a value close to that expected from the equivalent circuit design32. We further note, that although the original DS proposal was based on the hydrodynamic electron transport42, an identical photoresponse is expected outside the hydrodynamic window as it follows from the analysis of graphene’s nonlinear conductivity43.Another commonly accepted mechanism is the rectification arising as a result of the simultaneous action of longitudinal high-frequency field and modulation of channel conductivity, also known as resistive self-mixingτp extracted from the peak width at half-height are found to be below the momentum relaxation time. This suggests that other mechanisms of resonance broadening are also involved. In particular, leakage of plasma waves into metal contacts44 and electromagnetic dissipation in antenna may also contribute to the apparent resonance width. We have found that respective contributions to 45. Other dissipation channels such as electron viscosity47 and interband absorption18 should be most pronounced at higher-order harmonics and in the vicinity of the NP, as opposed to the data in Fig. Last but not least, we note that while the overall trend of the responsivity is well-described by the model introduced above, the values of 48.In conclusion, we have shown that high-mobility graphene FETs exploiting far-field coupling to incoming radiation can operate as resonant THz photodetectors. In addition to their potential applications in high-responsivity detection and on-chip spectroscopy of the THz radiation, our devices also represent a convenient tool to study plasmons under conditions where other approaches may be technically challenging. Due to their compact size and far-field coupling, our photodetectors can easily be employed to carry out plasmonic experiments in extreme cryogenic environments and in strong magnetic fields, as well in studies of more complex van der Waals heterostructures. As an example, we have demonstrated the use of our approach to reveal low-energy plasmons hosted by moiré minibands in BLG/hBN superlattices. The method has a strong potential for studies of collective modes in magnetic minibands which have recently gained a great level of attention30. The thickness of the top hBN was measured by atomic force microscopy. The stack was then deposited either directly on top of a low-conductivity boron-doped silicon wafer capped with a thin oxide layer (500 nm) or on a predefined back gate electrode. The resulting van der Waals heterostructure was patterned using electron beam lithography to define contact regions. Reactive ion etching was then used to selectively remove the areas unprotected by a lithographic mask, resulting in trenches for depositing electrical leads. Metal contacts to graphene were made by evaporating 3 nm of Cr and 60 nm of Au. Afterwards, a second e-beam lithography was used to design the top gate. The graphene channel was finally defined by a third round of e-beam lithography, followed by reactive ion etching etching using Poly(methyl methacrylate) and gold top gate as the etching mask. Finally, we used optical photolithography to pattern large antenna  sleeves connected to the source and the top-gate terminals, followed by evaporation of 3 nm of Cr and 400 nm of Au. Antennas were designed to operate at an experimentally accessible frequency range.All our devices were made of BLG. BLG was first encapsulated between relatively thick hBN crystals using the standard dry-peel techniquePhotoresponse measurements were performed in a variable temperature optical cryostat equipped with a polyethylene window that allowed us to couple the photodetector to incident THz radiation. The latter was focused to the device antenna by a silicon hemispherical lens attached to the silicon side of the chip Fig. . The traf = 0.13 THz and f = 0.46 THz. For higher frequencies, a quantum cascade continues wave laser based on a GaAs/Al0.1Ga0.9As heterostructure emitting f = 2.026 THz radiation was used.In order to study the photoresponse of our detectors at different frequencies, we used three radiation sources. Sub-THz radiation was provided by two backward wave oscillators (BWO) generating Udark was measured as a function of Vg in the dark. Then, the dependence of the source-to-drain voltage USD on Vg was recorded under illumination with THz radiation. The difference ΔU = USD − Udark formed the photovoltage. At the next stage, we measured the full power Pfull delivered to the cryostat window using Golay cell. The responsivity was then calculated as Ra = ΔU/P, where P ≈ Pfull/3.5 is the power delivered to the device antenna after accounting for losses in the silicon lens and the cryostat optical window (≈5.5 dB). All the measurements reported above were performed in the linear-in-P regime. The performance of our detectors outside the linear regime is discussed in Supplementary Note The responsivity of our devices was calculated assuming that the full power delivered to the device antenna funnelled into the FET channel. The as-determined value provides the lower bound for our detectors’ responsivity and is usually referred to as extrinsic. The calculation procedure consisted of a few steps. First the source-to-drain voltage Supplementary InformationPeer Review File


The paper presents the design and fabrication of a low-cost and easy-to-fabricate laser-induced graphene sensor together with its implementation for multi-sensing applications. Laser-irradiation of commercial polymer film was applied for photo-thermal generation of graphene. The graphene patterned in an interdigitated shape was transferred onto Kapton sticky tape to form the electrodes of a capacitive sensor. The functionality of the sensor was validated by employing them in electrochemical and strain-sensing scenarios. Impedance spectroscopy was applied to investigate the response of the sensor. For the electrochemical sensing, different concentrations of sodium sulfate were prepared, and the fabricated sensor was used to detect the concentration differences. For the strain sensing, the sensor was deployed for monitoring of human joint movements and tactile sensing. The promising sensing results validating the applicability of the fabricated sensor for multiple sensing purposes are presented. The deployment of flexible sensors for ubiquitous sensing has been receiving ever-growing research interest in recent times. Different kinds of flexible sensors have been developed using a wide range of processing materials and fabrication techniques ,9,10,11.Researchers have developed various graphene-based sensors exploiting the properties of pure and composite-based graphene ,20,21,22The second issue currently faced by the microelectronics industry is the lack of multifunctional sensors for monitoring purposes. Even though some researchers have recently worked on the development of graphene-based multifunctional sensors ,20,21,22In this paper, to address the aforementioned issues, we present a low-cost and easy-to-fabricate graphene-based sensor, together with its potential for multiple applications. We opted for a laser-induction process on commercial polyimide film to generate graphene, which was then transferred onto sticky Kapton polyimide tape through manual pressure by hand. The graphene layer is subsequently used as electrodes of the sensor prototype, whereas the Kapton tape is used as the substrate. We used the class of polyimide as the sensor substrate considering its advantages of high flexibility, biocompatibility, excellent chemical resistance and high tolerance strength . The novTo demonstrate its multi-functionality, we implemented the sensor in electrochemical and strain-sensing scenarios. For the electrochemical sensing, as a proof of concept, the sensor was used to test sulfate solutions at different concentrations. The motivation behind this idea is to emphasize the sensing of sulfate concentrations in the soil at a specific instant. As per literature , the sulThe remaining parts of the paper have been divided into five sections. In z-axis of the laser system. Power refers to the magnitude of the energy on which the laser nozzle operates. Speed (m/min) refers to the rate of movement of the laser nozzle over the sample in x-y directions. z-axis (mm) defines the focal point of the laser on the sample. The optimized values of these parameters were: 7 W of power, 70 m/min of speed, and 1 mm of z-axis.The fabrication process of the laser-induced graphene sensor is shown in graphene . The irrNext, the patterned graphene was meticulously transferred to commercial Kapton sticky tape (thickness of 0.1 mm), used as the substrate of the sensor. The process was done by placing the tape above the formed graphene and applying manual pressure over it, starting from the bonding pads and moving towards the electrode fingers. The graphene formed on the surface of polyimide film is very easy to shear off. The transfer of graphene to the sticky surface of Kapton tape therefore significantly improves the mechanical robustness of a laser-induced graphene-based sensor. Under a Scanning Electron Microscope (SEM), we also observed that the manual pressure applied during the transfer process leads to morphological changes of the graphene network, which include a more regular porosity, seemingly reduced thickness, and better interconnection between multilayer graphene flakes. The photo-thermal formation of graphene was not done directly on the Kapton tape, despite being made of polyimide, due to its stickiness that would cause an immediate agglomeration of the induced graphene, thus tampering the design of the electrodes. Moreover, Kapton tape provides a better physical robustness to the sensor than a thin polyimide film.The SEM images of the top view of the transferred graphene on Kapton tape are shown in One of the operating principles of the interdigitated capacitive sensor used in this work is based on the electrodynamics of two parallel plate capacitor as shown in L), width (W), and gap between interdigitated fingers (d)) and its electrical properties. Due to its flexible nature, any strain induced on the sensor leads to the change in its overall dimensions (Z) of the sensor changes, through which, therefore, strain can be sensed and quantified. In this work, we reported the sensor response in terms of magnitude of the complex total impedance . The responses of the sensor were analyzed through impedance spectroscopy. The experiment setup consisted of an LCR meter HIOKI IM3536 connected to a computer via a USB cable for data acquisition and storage. A Hioki 9140 4-terminal test probe with crocodile clip termination was used to connect the LCR meter with the sensor. All the experiments were operated in laboratory conditions at fixed temperature of 25 The preparation of the five samples was done through a serial dilution process. Anhydrous sodium sulfate  and deionized (DI) water were used as the solute and solvent, respectively. An initial solution of 10,000 ppm was formed by mixing 1 g sodium sulfate with 100 mL DI water to create the first sample. After the experiment with the first sample, 10 mL of this sample was pipetted to 90 mL of DI water to form the sample with the second concentration of 1000 ppm. This process was repeated until the fifth sample with a sulfate concentration of 1 ppm.terfaces ,and hencIt was also reported in  that parTo further highlight the consistency of the sensor responses implied in Prior to applying the sensor for sensing of human body-induced strains, we measured the sensor impedance as a function of frequency. In this case, we situated the sensor in four different conditions, i.e., flat and bent over three different curvatures. The aim was to briefly investigate the response of the sensor towards the change in its physical dimensions. The response is depicted in We further quantified the flexibility and the impedance characteristic of the sensor as a function of strain through a tensile-strength measurement by means of EXCEED E42 MTS Universal Test Device. The sensor was clamped firmly and the strain was applied to the sensor by moving the crosshead with a velocity of 0.2 mm/s in a perpendicular direction to the interdigitated fingers (see inset of The impedance response of the sensor corresponding to the level of the strain applied was also measured and shown in The setup for the human body-induced strains sensing are given in The responses of the sensor towards the first sensing scenario are shown The response of the sensor for the tactile sensing is shown in  polymer ,7. When  polymer . The effUnderstanding the importance of the sensor durability in strain-sensing applications, we have also conducted a long-term mechanical test. The repetitive bending-releasing cycle with approximately 10 mm bending radius was applied manually by hand to the sensor as illustrated in In this paper, we have presented the implementation of laser-induced graphene for realizing a flexible sensor for multiple sensing applications. The photo-thermal induction of polyimide film to generate the graphene and its subsequent use as electrodes on a flexible substrate allow for a low-cost, easy, yet effective realization of graphene-based sensor. The applications of developed sensor for various sensing purposes have also been demonstrated successfully. Firstly, we employed the sensor for electrochemically sensing the difference of sulfate concentrations in water samples. Secondly, the same sensor was employed for monitoring of the repetitive movements of elbow and finger joints as well as finger touches of a human subject. The sensitive responses of the sensor towards the given stimuli suggest the great feasibility of the proposed approach to realize a multifunctional flexible sensor. The performance of the sensor, however, can be improved further, for instance, by introducing selectivity on the electrodes towards specific ions through molecular imprinting polymer, as we demonstrated in ,50. This


Background: New biomarkers are urgently needed to facilitate diagnosis in Interstitial Lung Diseases (ILD), thus reducing the need for invasive procedures, and to enable tailoring and monitoring of medical treatment. Methods: In this study we investigated if patients with idiopathic pulmonary fibrosis , non-IPF ILDs (n = 57) and other lung diseases (chronic obstructive pulmonary disease (COPD) n = 24, lung cancer (LC) n = 16) as well as healthy subjects (n = 20) show relevant differences in exhaled NO , or in eicosanoid ) levels as measured in exhaled breath condensates (EBC) and bronchoalveolar lavage fluids (BALF). Results: There was no significant difference in FeNO values between IPF, non-IPF ILDs and healthy subjects, although some individual patients showed highly elevated FeNO. On the basis of the FeNO signal, it was neither possible to differentiate between the kind of disease nor to detect exacerbations. In addition, there was no correlation between FeNO values and lung function. The investigation of the eicosanoids in EBCs was challenging (PGE2) or unreliable (8-isoprostane), but worked out well in BALF. A significant increase of free 8-isoprostane was observed in BALF, but not in EBCs, of patients with IPF, hypersensitivity pneumonitis (HP) and sarcoidosis, possibly indicating severity of oxidative stress. Conclusions: FeNO-measurements are not of diagnostic benefit in different ILDs including IPF. The same holds true for PGE2 and 8-isoprostane in EBC by ELISA. Interstitial Lung Diseases (ILD) in general, and idiopathic pulmonary fibrosis (IPF) in particular, are complex disorders with different pathogenetic pathways, heterogenous disease behavior, with great variability in disease severity and rate of progression, as well as different responses to treatment . IPF is Safe diagnosis of ILD’s can be notoriously difficult, since the number of differential diagnoses is usually large and the clinical and radiographic (high-resolution computed tomography—HRCT) phenotype patterns can be incomplete or overlapping ,7. For tInternational consensus guidelines recommend that the diagnosis of IPF should be made at a multi-disciplinary level, in order to increase the specificity of the diagnostic process, especially in those cases with overlapping or incomplete patterns . Hence, Biomarker research has been undertaken using peripheral blood, bronchoalveolar lavage fluid (BALF), and exhaled breath condensate (EBC) . NumerouHowever, there is currently no established biomarker in routine use for diagnosis and assessment of prognosis in ILD, and this holds particularly true for non-invasive markers. With regard to non-invasive markers, one pathway of interest for non-invasive detection is the free radical nitric oxide (NO), which is regulated by three isoforms of nitric oxide synthase (NOS), neuronal NOS, inducible NOS and endothelial NOS (eNOS). Several reports showed that NO plays an important role in the development of pulmonary fibrosis ,18. NO iFeNO has been shown to be useful for the diagnosis of eosinophilic airway inflammation especially in asthma, and for determining steroid responsiveness in chronic respiratory inflammation, with a focus on avoiding unnecessary steroid therapies ,21,22. WOther volatile substances of potential interest are prostaglandin E2 (PGE2) and 8-isoprostane. PGE2 is a known antifibrotic mediator that plays an important role in pathogenesis of wound resolution and also been shown to be an important negative regulator of fibroblast activation and collagen expression released by an intact alveolar epithelium ,25. InhaIn the present study we therefore evaluated the diagnostic potential of FeNO, PGE2 and 8-isoprostane in EBCs in different ILDs and other lung diseases. Unfortunately, none of these markers turned out to have any diagnostic or prognostic potential.In this study, a total of 138 patients , 16 lung cancer (LC) and 20 healthy controls (HC)) from the Giessen site of the European IPF registry (eurIPFreg), have been analyzed on the basis of clinical data as well as obtained biomaterials.The eurIPFreg is an Internet-based, multicentre registry linked to the European IPF Biobank (eurIPFbank). The data protection concept was accepted by local and national networks such as the TMF  and official authorities . Both, eurIPFreg and eurIPFbank were permitted by institutional review boards in Germany and Europe . The research was conducted strictly according to the principles of the Declaration of Helsinki. The eurIPFreg and eurIPFbank are listed in ClinicalTrials.gov (NCT02951416).Patients above 18 years with IPF, other ILD’s, or other non-ILD lung diseases (as disease controls), who signed the informed consent, were selected for this study. The diagnosis of IPF was based on the American Thoracic Society (ATS) criteria .The clinical data were collected at the time of enrolment  and in intervals of 3 to 12 months thereafter (follow up) via patient and physician baseline and follow up questionnaires, which in total comprised of 1700 variables [Biological materials such as blood, bronchoalveolar lavage fluid (BALF), tissue samples as well as exhaled breath condensates and EBCs were centrally managed through generation of patient-, time-, and specimen-specific Lab IDs; they were stored in the centralized European IPF Biobank (eurIPFbank) located in Giessen, Germany. Patients were asked to withdraw from food and nicotine intake a few hours prior to the measurements, as well as to rinse the mouth before analyses. A nose clip was consistently used. The FeNO measurements were carried out with the device NIOX Mino . EBCs were collected according to the recommendations of the ATS/European Respiratory Society (ERS) Working Group with the turbo-DECCS device  . The turThe quantitative detection of PGE2 and 8-Isoprostan in biomaterials was performed using a commercially available immunosorbent assay . It is based on an enzymatic immune assay (EIA) principle. In case of BALF, samples were directly transferred to the wells of the plate. In case of EBCs, we analyzed EBC fluid directly, as well as after concentrating its content. For this purpose, 600 μL of each sample were lyophilized in the vacuum centrifuge and dissolved thereafter in distilled water at a volume of 120 µL.Quality of data in the eurIPFreg was maintained through internal plausibility checks, in which different items were put into a logical context, causing the generation of queries in case inconsistent entries were noted . These queries were addressed by the respective site investigator, asking for clarification of the issue.t-test, Mann–Whitney U test, or a linear regression analysis. Correlation coefficient was determined by Spearman. The Chi²-test was used for nominally distributed characteristics. The results with a p < 0.05 were reported as statistically significant. The results were evaluated with the program GraphPad Prism 5 .All statistical procedures were performed using SPSS 24 . For baseline data, the summary descriptive statistic was generated with categorical data displayed as absolute numbers and relative frequencies. Continuous data are shown as mean (SD) for normally distributed data or as median (interquartile range) for nonparametric data. Comparisons between groups were performed using a In total, FeNO measurements could be performed in the 94 patients of different groups. The demographics data together with clinical and pulmonary function (PFT) parameters are outlined in p = 0.03) as well as an inverse, highly significant correlation between FeNO and residual volume/total lung capacity RV/TLC  were observed. The data are shown in All groups showed a similar range of FeNO values . In ordeTo further analyze the relationship between exercise capacity and FeNO in IPF, the values were correlated with the walking distance of the six-minute walk test (6MWD) and the VO2max values of the spiroergometry. There was no relevant correlation of the FeNO values with the 6MWD, either when restricted to IPF patients alone , possiblTo clarify the extent to which smoking behavior and drug intake influence the FeNO values, the FeNO values for all patients were analyzed in dependency of the following subgroups: Smoker status , as well as intake of medication , steroids and proton pump inhibitors (PPI)).To this end, actively smoking patients showed significantly lower FeNO levels than former smokers and never smoked patients . The medThe intraindividual variability of FeNO was determined by repeated analyses (from 1 to 11 days between the measurements) in the IPF and COPD cohorts . OverallTo evaluate the impact of exacerbation on FeNO, we analyzed FeNo values of the whole cohort  as well The free 8-isoprostane in the exhaled breath condensate (EBC) was measured with a commercial ELISA (Cayman). In general, when analyzing EBC directly, the values were in the lower range of the standard curve and in a number of cases even below that. We therefore analyzed EBC after concentrating its content. In In BALF, the free 8-isoprostane, but not total 8-isoprostane, values were found to be significantly higher in IPF, HP and sarcoidosis as compared to healthy controls A,B.In the EBC, PGE2 was difficult to detect and each single patient sample yielded values below the smallest standard. Samples were therefore concentrated by lyophilization and again analyzed for PGE2 determination, all of which were measurable for PGE2 . In general, it was neither possible to differentiate between the kind of disease, to detect exacerbation or to correlate FeNO or eicosanoid values with lung function parameters DLco or 6MWD. In addition, analysis of arachidonic acid derivates in EBC was challenging (PEG2) or impossible (8-isoprostane), whereas it worked out well in BALF. Some group-specific, significant differences were observed with regard to free 8-isoprostane in BALF, the meaning of which appears questionable in light of the unchanged total 8-isoprostane values and the missing correlation to progression of disease.Previous studies have shown that measurement of FeNO appears to be a quantitative, non-invasive, simple and safe method of measuring airway inflammation and to assess activity of airway disease, especially in asthma . In our In our study, a good reproducibility of FeNO results has been proven, which is in line with other studies, where FeNO measurements demonstrated high reproducibility and low daily variability in healthy and asthmatic children and adults . We did When interpreting FeNO measurements, individual factors should always be considered. In adults, a positive correlation was observed between the FeNO levels and age of the patients . We alsoThe effect of steroids on the FeNO values had been discussed differently in the literature and seems to depend on the underlying disease and its pathomechanism . LehtimäWith regard to changes in FeNO in IPF, Saleh et al. showed that NO values might be upregulated in IPF patients, with a significant increase in early to intermediate stage of the disease, suggestive of a valuable role of constitutively produced NO in pulmonary homeostasis and of a protective effect on lung architecture . In his Paredi et al. showed elevated FeNO values in IPF patients (MW with SD: 11.2 ± 1 ppb) compared to healthy non-smokers (6.9 ± 0.5 ppb) (flow rate: 5 L/min = 83.3 mL/s) . The FeNn: 30) at different flow rates. At 50 mL/s IPF patients showed similarly high levels  as those reported by Guilleminault, but were lower as compared to Schildge et al.  [In another study, Cameli et al. compared FeNO values in idiopathic interstitial pneumonitis (IIP) patients  and healthy controls (MW ± SD) ,40. AgaiMW ± SD) .With regard to the eisocanoid measurements, it had been previously suggested that PGE2 is down-regulated in IPF patients, thus favoring the development of pulmonary fibrosis ,42. In IFree and total 8-isoprostane are markers for oxidative stress-induced lipid peroxidation. Elevated levels of free 8-isoprostane have been used as markers of oxidative stress in asthma, COPD, pulmonary sarcoidosis, ILD and IPF ,44. MontOne of our study limitations was the sample size in the ILD subgroup analysis. In addition, we reported the results of the consecutive patients without withdrawal of any medication, thus it might not reflect the natural course of the lung diseases. Especially in the pirfenidone group, one could assume the possible influence this medication has on the FeNO levels. Further studies, taking into account a larger number of patients and longer follow up periods, are recommended to deeper evaluate the role of biomarkers in diagnostic and prognosis of interstitial lung diseases.In summary, no significant and meaningful difference in the FeNO, PGE2, or 8-isoprostane values in EBC or BALF could be observed between different forms of ILD’s, especially IPF, and other lung diseases such as COPD or LC and healthy controls. In addition, we failed to observe a relevant correlation of these values with lung function, gas exchange or exercise parameters or with exacerbation or treatment status.Therefore, our results do not support previous studies in IPF patients and other ILDs, according to which NO is an important marker for the assessment of disease severity. To our understanding, FeNO or PGE2 or 8-isoprostane measurements in BALF do not offer as diagnostic or prognostic markers, nor do they indicate exacerbation.


GluTTC, which promoted preadipocyte proliferation by increasing expressions of cell cycle regulatory factors, had the highest fold change in the 296 differentially expressed tRFs. Moreover, tRFGluTTC also suppressed preadipocyte differentiation by reducing triglyceride content and lipid accumulation, and by decreasing expressions of genes that related to fatty acid synthesis. According to results of luciferase activity analysis, tRFGluTTC directly targeted Kruppel-like factor (KLF) 9, KLF11, and KLF12, thus significantly suppressing mRNA expressions of these target genes. Moreover, tRFGluTTC suppressed adipogenesis, accompanying by suppressing expressions of adipogenic transcription factors . In conclusion, these results imply that tRFGluTTC may act as a novel epigenetic molecule regulating adipogenesis and could provide a new strategy for the intervention treatment of obesity.tRNA-derived fragments (tRFs), a novel type of non-coding RNA derived from tRNAs, play an important part in governing gene expressions at a post-transcriptional level. To date, the regulatory mechanism of tRFs governing fat deposition and adipogenesis is completely unknown. In this study, high fat diet was employed to induce an obese rat model, and tRFs transcriptome sequencing was conducted to identify differentially expressed tRFs that response to obesity. We found out that tRF Currently, epidemic obesity is seriously affecting humans’ health worldwide. Obesity is also associated with high occurrence risks of multiple diseases, such as cardiovascular disease, type II diabetes, hypertension, respiratory disease, and a variety of cancers . ObesityIn recent decades, non-coding RNAs are known as pivotal epigenetic molecules regulating almost all biological processes, including adipogenesis. Furthermore, many miRNAs, lncRNA, and circRNAs have been proved to govern adipogenesis tightly ,6,7. RecTo verify this hypothesis, deep tRFs sequencing was conducted to identify vital tRFs involved in fat deposition in vivo, and 3T3-L1 preadipocyte was employed to verify functions of tRFs on adipogenesis in vitro. These studies imply that tRFs may act as novel epigenetic molecules for intervention treatment of obesity and metabolic syndrome.n = 8) and HFD . After 100 days of feeding, a glucose tolerance test (GTT) was conducted on rats following our previous study [In this study, animal care and all procedures were performed according to instructions of Institutional Animal Care and Use Committee of Sichuan Agricultural University, Sichuan, China, under permit No. DKY-B20131403 . Sixteen 6-week-old male Strague Dawley (SD) rats were randomly divided into two groups: LFD  for tRFs sequencing. Briefly, fractions of 15–40 nt were excised and purified from total RNA, and obtained small RNA fractions were used to construct tRFs sequencing library through ligating adapters and RT-PCR reaction. Raw datum files in FASTQ format were generated through Illumina Hi-Seq 2500 platform. The process of tRFs-seq datum analysis was carried out following a previous study . All tRFGluTTC mimics (5′- TCCCACATGGTCTAGCGGTTAGGATTCCTGGTTTT-3′) and specific chemically modified inhibitors  were designed and synthesized by RiboBio , and then transfected into 3T3-L1 cells by mixing with Lipofectamine 2000 reagent . Briefly, 2 μL mimic (20 μM) or 4 μL inhibitor (20 μM) with lipid carrier  were subjected to transfection in 500 μL Opti-MEM medium for each well in standard 24-well plates. CCK-8 and EdU assays were conducted following operation instructions to survey the proliferation rate of 3T3-L1 after transfecting with tRFGluTTC mimics or inhibitors. Differentiated 3T3-L1 cells, which were transfected with tRFGluTTC mimics or inhibitors, were stained with Oil Red O (60% saturability), and triglyceride assay was operated using a detection kit . For the luciferase reporter analysis, modified psiCHECK™-2 vectors were constructed by inserting wild-type and mutant KLF family 3’-UTR into psiCHECK™-2, respectively. Then HeLa cells were cultured to detect luciferase activities after co-transfecting with modified psiCHECK™-2 vectors and tRFGluTTC mimics, respectively. Dual-Glo Luciferase Assay System  was employed to test luciferase activities. tRFs and mRNAs quantification were performed according to our previous study [t-test, the level of statistical significance was set at p < 0.05. 3T3-L1 cells were proliferated and differentiated, and then transfected with mimics and inhibitors following steps in our previous study . tRFGluTus study . All datp < 0.05), which were consistent with previous studies reported about the prototypical phenotypes of an obese model [p < 0.05) (p < 0.05). Therefore, considering these findings, we believe that the obese model used in this study was successful.To investigate functions of tRFs on fat deposition and adipogenesis, SD rats were employed to construct the obesity model. As shown in se model . Additio < 0.05) E,F. FurtTo explore the differences of tRFs profile in adipose in response to the stress of obesity, perirenal fat sampled from the HFD and LFD groups was performed with tRFs transcriptome sequencing 15–40 nt). As shown in –40 nt. AGluTTC in this study. These results were consistent with previous studies reporting that tRNA-derived tRFs were not random products of tRNA fragments, but possessed tissue-specific characteristics [GluTTC has 7-mer complementary sequences with KLF family, such as KLF9, KLF11, KLF12, and KLF13. Previous studies have reported that transcription factors from KLF family were important regulators of adipogenesis [GluTTC, a double fluorescent reporter analysis was carried out. As shown in GluTTC mimics and WT-KLF12/WT-KLF9/WT-KLF11 could significantly decrease the relative luciferase activity (p < 0.05). However, decreasing of luciferase activity was not observed in HeLa cells co-transfected with tRFGluTTC mimics and mutant-KLF13 luciferase plasmids. To sum up, these data indicate that tRFGluTTC targeting KLF family might be one of the potential epigenetic regulatory pathways in governing adipogenesis. Recently, a number of evidences proved that tRFs had similar functions as miRNAs by guiding Ago2 to regulate target gene expressions . Howevereristics . The resogenesis ,19,20. Fogenesis . To furtGluTTC may play other important roles in regulating adipogenesis based on the fact that tRFGluTTC directly targets KLF family genes. In this study, 3T3-L1 preadipocytes, a widely used adipocyte differentiation model, were used to further explore the pathways of tRFGluTTC involved in adipogenesis. Based on the results of CCK-8 assay, we found out that the proliferation rate of 3T3-L1 preadipocytes increased when tRFGluTTC overexpressed, but it decreased when the expression of tRFGluTTC decreased , and Cyclin E were essential factors for maintaining G1/S phase transition in mammalian cells [GluTTC mimic group, while knockdown of tRFGluTTC could significantly decrease CDK4 and Cyclin E expression. Thus, all data together indicate that tRFGluTTC could promote 3T3-L1 preadipocyte proliferation. Previous studies have reported that tRFs derived from tRNA-Glu-TTC were closely related with moyamoya disease and triple negative breast cancer ,23. Howeecreased A. These an cells ,25. As iGluTTC in adipogenesis, the differentiation extent of 3T3-L1 cells that transfected with tRFGluTTC mimics or inhibitors were measured. After eight days of differentiation, according to Oil Red O staining results, overexpression or knockdown of tRFGluTTC significantly suppressed or promoted 3T3-L1 differentiation, respectively (GluTT mimics or inhibitors into 3T3-L1 could significantly suppress or promote mRNA expressions of KLF9, KLF11, and KLF12, respectively (GluTTC directly targeting KLF9, KLF11, and KLF12. aP2, C/EBPα, and PPARγ were essential transcription factors for regulating adipogenesis [GluTTC could significantly decrease and increase expressions of genes related to fatty acid oxidation and fatty acid synthesis, respectively. On the contrary, knockdown of tRFGluTTC had opposite results (GluTTC could suppress 3T3-L1 preadipocyte differentiation.Lipid accumulation in adipose tissues is on the basis of adipocyte proliferation and differentiation. To further identify the function of tRFectively E. These ectively F. Moreovectively G, which ogenesis , and all results I. The exGluTTC had the highest fold change of tRFs, which could directly target KLF family, such as KLF9, KLF11, and KLF12. Overexpression of tRFGluTTC significantly promoted 3T3-L1 preadipocyte proliferation, but significantly suppressed 3T3-L1 differentiation. Thus, these findings imply that tRFs may act as novel epigenetic molecules for governing adipogenesis.In summary, our study firstly investigated variations of tRFs profile in response to the stress of obesity. A total of 296 differentially expressed tRFs were found between normal and obese adipose tissues. Interestingly, tRF


Graphene is a remarkable two-dimensional (2D) material that is of great interest to both academia and industry. It has outstanding electrical and thermal conductivity and good mechanical behavior with promising applications in electronic devices, supercapacitors, batteries, composite materials, flexible transparent displays, solar cells, and sensors. Several methods have been used to produce either pristine graphene or doped graphene. These include chemical vapor deposition (CVD), mechanical exfoliation, decomposition of SiC, liquid-phase exfoliation, pulsed laser deposition (PLD). Among these methods, PLD, which is routinely used for growing complex oxide thin films has proved to be an alternative to the more widely reported CVD method for producing graphene thin films, because of its advantages. Here we review the synthesis of graphene using PLD. We describe recent progress in preparing pristine graphene and doped graphene by PLD, including deposition processes and characterization. The goal of this complete survey is to describe the advantages of using the technique for graphene growth. The review will also help researchers to better understand graphene synthesis using the PLD technique. Graphene is considered to be an emergent 2D material for modern science because of its unique versatile properties including high conductivity, transparency, strength, and thermal conductivity with many potential applications in research and industry as transparent electrodes, field emitters, biosensors, batteries, composites, and so on , the rhombohedral stacking (ABCABC)  are deposited directly onto the substrate. The principle behind the PLD mechanism can be briefly described as follows. The focused laser beam, striking the surface of a solid target during a short time, induces an energetic plasma plume containing ions and atoms, impinging the substrate in front of the target. Depending on various process parameters, including the substrate temperature, a single-crystal, polycrystalline or amorphous film can be obtained . Since then, many others groups have used PLD to synthesize graphene. Tables In the context of graphene growth, PLD provides an alternative way to control the thickness and composition of the graphene precursor, by laser wavelength and power, to that of CVD, where control is achieved by temperature and gas pressure .To mention just a few, Kumar and Khare  demonstr2D/IG ~ 0.5, and an estimated crystallite size of ~38 nm. The transmittance of these samples was found to be around 95%.Another work highlighted the technique to grow few-layer graphene on non-metallic substrates using KrF excimer laser ablation of ordered pyrolytic graphite (HOPG) during different ablation times at 750°C without a metal catalyst  and the grain size was about 40 nm. This demonstrated the formation of few-layer graphene with high transmittance without a metal catalytic layer using the PLD technique at low temperature with small grain size.in situ using ultraviolet pulsed laser deposition in the presence of nitrogen on Si/SiO2 substrates without the need for a metal catalytic layer. Different nitrogen doped graphene was grown with different nitrogen concentrations and the highest value was 3.3 at% of N. The authors clearly demonstrate the production of N-doped graphene thin film using a PLD technique, since two components “pyridinic,” and ”pyrrolic” N of N1s peak can be observed. In the same study, the authors also reported that the nitrogen-doped graphene chemically enhanced the Raman signal compared to pristine graphene and that the nitrogen content could be modulated by adjusting the nitrogen gas pressure.In a recent study, Ren et al.  grew nitIn short, it is clear that the PLD way of growing graphene without a metal catalytic layer is satisfactory for direct one-step synthesis of graphene and doped graphene on different substrates. However, up to now, this technique has only enabled the production of few-layer or multi-layer graphene but not monolayer. Still, it is the only physical vapor deposition method that makes it possible to avoid the transfer process after graphene growth and is a way forward in the graphene and doped graphene synthesis field.Using a catalytic metal layer is one of the most widely used methods of producing graphene either by CVD and by PLD. To obtain graphene on a metal catalytic layer, free standing graphene is obtained by etching with acid and then transferring it onto another substrate of choice, which may be the most effective method. When grown on a metal layer, the resulting graphene has more uniform layers compared to mechanical exfoliation producing graphene in a wide range of thicknesses  active substrate for molecular diagnostics.In their study, Tite et al.  reportedRecently, another work  by pulsed laser ablation of a highly ordered pyrolytic graphite target, using a pulsed nanosecond Q-switched Nd:YAG laser at 355 nm (3.5 eV) and a Ni catalytic layer. According to the authors, a few layers of graphene were deposited at a substrate temperature of 800°C, whereas multi-layer graphene was formed at a lower substrate temperature of 750°C. Therefore, the number of graphene layers was reduced while defects increased, when the growth temperature was increased. Thus, the number of graphene layer can be controlled (4–5 layers) by adjusting the growth temperature. Figure Recently, Kumar et al.  producedIn an another recent study using the a-C/Ni/substrate stacking configuration, Dong et al.  demonstrAs illustrated in Figures D/IG and I2D/IG values are summarized in the table, and the I2D/IG value of 0.69 for the film on the double-layer catalyst corresponding to 3–4 layers. The resulting samples were transferred onto SiO2/Si substrates and the measured electrical resistivity was as low as 0.34 mΩ.cm.From the Raman results in Figure a-C/Ni/substrate. In contrast, few studies have been performed using PLD for the first stacking configuration Ni/a-C/substrate. However, using this order makes it possible to elucidate the diffusion mechanism of carbon in nickel during the formation of graphene. For instance, Weatherup et al. , ~ 283.8 eV (CDis), ~ 284.4 eV (CGr), and ~ 284.8 eV (CB). The CA and CDis components appears first during heating, and were assigned to carbon bound to Ni surface sites, and interstitial carbon dissolved in the Ni catalyst, respectively. CGr and CB peaks appeared simultaneously some time later, corresponding to the formation of graphitic carbon at the catalyst surface and the disordered sp3 carbon, respectively. For the Ni 2p3/2 core level spectra, two main components NiM  and NiDis  were detected. The metallic Ni is more surface sensitive and the interstitial solid solution of C in Ni is bulk sensitive.To sum up, graphene has been grown by many groups using the PLD technique with a nickel catalytic layer and two stacking orders: Ni/a-C/substrate and p et al.  used thiConversely, many studies have been performed on the second stacking order for graphene growth. One of the main difference between the two stacking orders is that with the second configuration (a-C/Ni/ substrate), technically, the Ni catalyst can be heated while depositing the solid carbon source. This procedure can increase the nickel grain size and consequently enlarge the grain size of the resulting graphene. However, the difference in the formation, and the type and quality of the graphene between these two stacking orders requires further research.According to the studies summarized in Table It is worth mentioning that the production of graphene using both stacking orders and Ni catalyst has been achieved with other methods such as thermal annealing , cobalt (Co), tin (Sn), iron (Fe), and Cu-Ni alloys as catalysts has also been reported.Koh et al.  publishe2 laser ablation of pyrolytic graphite target placed in a vacuum chamber at a pressure of 10−6 Torr, Kaushik et al.  signals of molecules, such as pesticides or pollutants for environmental safety.2OH)2) redox probe on the graphene film was shown to be reversible (ΔEp = 59 mV and Ip/Ia = 1) at scan rates below 20 mV/s for few-layer graphene. At higher scan rates, electron transfer kinetics becomes quasi-reversible (ΔEp >59 mV and Ip/Ia = 1).Fortgang et al.  reportedThe ethynyl aryl groups were shown to be successfully and robustly attached to the graphene surface, paving the way for the specific attachment of molecules bearing an azide function using the click reaction. The method was applied to ferrocene-azide to model the grafting of redox molecules on the graphene layer Figure .The electrochemical response of the functionalized electrode was studied. The authors confirmed that this addressing method was efficiently controlled by electrochemistry, showing high loading of ferrocene and a stable electrochemical response of the electrode over a period of 22 days. The quantity of the grafted molecules was higher than on other frequently used substrates such as glassy carbon or BDD due to a multi-layer grafting structure. High loading of recognition elements on the electrode should thus be possible. This method allows electrochemically controlled functionalization for addressing probes on a multielectrode device. This work opens highly promising perspectives for the development of self-organized 3D graphene electrodes with different sensing functionalities and can be applied to fragile sensing objects such as biomolecules or living systems.In the transparent electrode field, Xu et al.  demonstrGraphene has remarkable properties that promise a wide range of possible applications including electronic devices, supercapacitors, batteries, composites, flexible transparent displays, solar cells, and sensors. In order to achieve the full potential of graphene material, samples of graphene of high quality, uniform morphology and large area are required. The PLD technique is appealing for the growth of graphene materials as an alternative to the conventional CVD technique. This review provides an overview of the synthesis of graphene and doped graphene deposited using the PLD technique and some potential applications. Based on the results reported here, PLD graphene of different types and of different quality, from high to low, from single to multilayer can be produced, depending on the specific growth conditions, including substrate temperature, the energy density of the irradiated laser on the target, the background pressure, annealing rate, and time invested. In addition, compared to the graphene obtained by other commonly used methods, such as mechanical exfoliation, chemical and liquid exfoliation, CVD, PLD graphene growth has the advantage of good adhesion to the substrates, rapid speed of growth and relatively low production temperature. However, PLD single layer graphene has not been obtained so far. PLD graphene is sometimes a mixture of single, bilayer, trilayer, few-layer, and multi-layer graphene. The growth conditions consequently need to be optimized in order to combine high quality with large area graphene and single layer graphene.Compared with the extensive studies on CVD graphene materials, the use of PLD graphene is quite recent and requires a more detailed understanding of the mechanisms involved and of the optimal deposition conditions. Some of the challenges that remain are listed below:The synthesis of PLD graphene requires a relatively long period to optimize the deposition conditions because the fundamental mechanism of growth is not yet fully understood.Up to now, PLD graphene using metal catalyst is mostly prepared with Ni catalyst. Few studies report PLD graphene growth using other metal catalysts. Graphene growth on the other catalyst e.g., Cu, Co, Fe, Ag, Ni-Cu using PLD is thus worth exploring. In addition, using a metal catalytic layer in graphene growth represents an additional key parameter: the ratio of the thickness of the metal layer to that of the carbon layer. This ratio depends on the metal used and needs to be optimized in order to produce high quality graphene.Doped graphene can be produced using PLD. Nevertheless, up to now, only two studies have reported on nitrogen-doped graphene (n doping) and none on boron-doped graphene (p doping) using PLD. This could be a promising direction to study the effects of doping on PLD graphene in the future.From the point of view of the type of laser, many studies have reported PLD graphene growth using excimer nanosecond laser, while only a few studies report on femtosecond laser. It would thus be interesting to compare PLD graphene obtained using nanosecond laser and femtosecond laser, since laser directly influences the nature of the carbon-based film used as precursor of the graphene film.Lastly, the synthesis of graphene is fundamental for all studies in terms of property and applications. Simple methods are still needed to easily control crystallinity, grain size, grain boundaries, layers and output, and high-fidelity transfer. In the past, PLD has proven to be a powerful tool to deposit a single layer of thin film. Today, it is believed that PLD will play an important role in making graphene and doped graphene materials for various applications in the future. At the same time, understanding the growth mechanism needed to produce high quality, uniform, large area graphene using PLD is indispensable. Since it is clear that no single parameter is responsible for large-area, high quality graphene, all the growth conditions need to be optimized to achieve the same or better quality graphene than that grown using CVD or mechanical exfoliation techniques.YB wrote the main part of the proof. FB, TT, CM, and A-SL have performed many experiments described in the proof. CD and FG supervised the experimental work and have completed the proof.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Clinicians frequently have questions about patient care. However, for more than half of the generated questions, answers are never pursued, and if they are, often not answered satisfactorily. We aimed to characterise the clinical questions asked and answers provided by general practitioners (GP) through posts to a popular professional social media network.In this cross-sectional study, we analysed clinical questions and answers posted between January 20th and February 10th 2018 on a popular GP-restricted  Facebook group. Each clinical question was categorised according to ‘background’ or ‘foreground’ question; type ; and the clinical topic (e.g. cardiovascular). Each answer provided in response to included questions was categorised into: (i) short answer (e.g. agree/disagree); (ii) provided an explanation to justify the answer; and (iii) referred to a published relevant evidence resource.n = 87; 43%) and diagnosis . Five major topics  accounted for 118 (58%) questions. Each question received on average 10 (SD = 9) answers: 42% were short; 51% provided an explanation; and only 6% referred to relevant research evidence. Only 3 answers referred to systematic reviews.Of 1060 new posts during the study period, 204 (19%) included a clinical question. GPs most commonly asked about treatment (In this sample of Australian and New Zealand GPs, who were members of a GP social media group, GPs asked clinical questions that can be organised into a limited number of question types and topics. This might help guide the development of GP learning programs. There has been a rapid expansion of information in health care over the last few decades . The chaA systematic review of clinical questions raised by clinicians showed that clinicians ask about 1 question every 2 patients . HoweverIn this cross-sectional study, we analysed all clinical questions posted on a popular GP-restricted Facebook group ‘GPs Down Under’ between January 20th and February 10th 2018. ‘GPs Down Under’ is a GP community-led closed professional Facebook group restricted to GPs practising in Australia and New Zealand. It has over 5800 members and generates over 50 posts per day.The criteria for GPDU group membership include being a GP or a GP registrar and working in general practice with registration to practice in Australia and/or New Zealand. A three-step verification procedure is used. Two of the co-authors (KM and KP) were co-developers and are administrators of the GPDU Facebook group.Two of the co-authors (KM and KP) scraped all the data  of the posts that were posted during the study period. One of the authors who is also a member of GPDU (PG) de-identified the data and developed a de-identified anonymised dataset for screening and analysis.We screened all posts that were posted to the group during the study period to identify those that included a clinical question  included a clinical question. Of these 204 included questions, 174 (85%) were foreground and 30 (15%) background questions. The characteristics of clinical questions posted to GPDU group are presented in Table n = 118; 58%) concerned five major clinical topics. The five most frequently addressed topics were skin , mental health , cardiovascular , women’s health , and musculoskeletal . Table The clinical question topics were fairly distributed across all the clinical topics reflecting the range of patients seen by GPs. However, over half of all included clinical questions  comments per included question . GPDU members commented and provided answers for all 204 included questions. On average, 10 (SD 9) of the 20 (SD 19) comments were answers to the posted question; the remaining comments did not answer the clinical question originated in the post. On average, 42% (SD 27%) of these answers were short answers; 51% (SD 27%) were answers which provided an explanation or justification to the answer; and 6% (SD 11%) referred to published relevant evidence resource. Only three answers referred to evidence derived from systematic reviews  at the point of care and found that the majority of clinical questions concerned treatment (34%) and diagnosis (24%) - with 30% of the question types accounting for 80% of the questions asked . SimilarDespite the wide spectrum of clinical presentations seen by GPs in practice, we found that most of the clinical questions asked about a handful of clinical topics. This is consistent with frequencies in previous studies of the most frequently asked clinical questions’ topics , 16, andIn this sample of GPs evidence-based resources (e.g. systematic reviews) were infrequently used to support answers to the posted clinical questions. This aligns with the findings of a systematic review of 19 studies that described information seeking behaviour of clinicians and found that evidence-based resources were rarely used by clinicians as a primary source of information to guide their decisions , 19.A limitation of this study is that we focused on questions that GPs pursued, articulated, and posted a clinical question to find an answer (i.e. known unknowns), but we likely missed their unpursued recognised questions as well as their unrecognised questions (i.e. unknown unknowns). Direct observation studies and post-consultation interviews may better capture the information needs of clinicians at point of care (i.e. less susceptible to memory bias), although these methods might generate superfluous questions from clinicians because they are being observed or interviewed , 16. NorOur findings that the majority of questions asked were about a limited number of questions types and topics suggest that questions raised on social media networks may be helpful in guiding the development of GP future continuous learning programs (e.g. tailored according to identified information needs) and research activities (e.g. by identifying research-practice evidence gaps) . AlthougIn this sample of Australian and New Zealand GPs, who were members of a GP social media group, the majority of clinical questions asked were about a limited number of questions types and topics which may help inform the development of GP future continuous learning programs and research activities. The validity of the evidence underpinning the answers provided for clinical questions asked in social media needs to be considered.


Transfer method of chemically vapor deposition graphene is an appealing issue to realize its application as flexible and transparent electrodes. A universal stamping method to transfer as grown graphene from copper onto different flexible and transparent polymers (FTPs) reported here ensures simple, robust, rapid, clean and low-cost. This method relies on coating ethylene vinyl acetate (EVA) onto the as grown graphene, binding EVA coated graphene/Cu with FTPs and delamination by hydrogen bubbling process, which is analogous to the method used by stamping process where ink carries the imprint of the object onto any materials. The fate of the stamping method depends on how strongly the adhesion of EVA coated graphene/Cu with target FTPs. Interestingly, we have found that the thin film of EVA/graphene/Cu can only bind strongly with the FTPs of less than 25 µm in thickness and lower glass transition temperature value to the EVA while wide range of other FTPs are considered upon surface engineering to enhance the binding strength between FTPs and EVA. What’s more, the electrical performance was investigated with a demonstration of triboelectric nanogenerators which confirmed the reliability of graphene transfer onto the FTPs and prospect for the development of flexible and transparent electronics. Large domain size graphene grown on Cu may explore the possibilities of realistic application upon transfer onto the dielectric substrates9. Graphene on polymer substrates are especially appealing as replacement of Indium tin oxide (ITO) and also one of the essential flexible and transparent electrodes for a wide range of optoelectronics devices such as touch screen displays and solar cells12. Polymethyl methacrylate (PMMA) polymer is used to transfer graphene from Cu metal substrate onto the dielectric substrates14, but only limited to study for the fundamental properties. Till date, as grown CVD graphene was transferred onto many different types of flexible polymers21. In majority of transfer case, PMMA and thermal releasing polymers are used as intermediate polymer to transfer graphene onto different polymers which scarifies the Cu substrates and induces cracks22. Roll to roll transfer of graphene onto polyethylene ptherapthalate (PET) was also achieved via thermal release tape10, epoxy resin15 and ethylene vinyl acetate(EVA)23 as binding source between graphene and PET. Roll to roll graphene transferred onto the EVA/PET by bubbling method24 and green transfer23 is hopeful to achieve the low cost, light weight, flexible and transparent electrodes. To our best of knowledge there is no report found on graphene transfer onto many other polymers, except PET, using EVA as binding agent for the industrial scale. EVA is explored against PMMA mediated graphene transfer for conformal contact with the target substrates26. Graphene transfer onto different polymers of characteristics properties suits wider range of applications still remains challenging and not many efforts have been made in this direction27. Recent advances in flexible electronics expect to soon realize the industrial production of graphene based hybrid transparent electrodes28. Our study met the challenge to transfer graphene onto different polymers by a fast and clean process.Since the discovery of mechanically exfoliated graphene29, is the major role in this transfer process. Next generation of wearable/bendable electronics demands the potential supply of flexible and transparent polymers as transparent electrode substrates in the areas of energy conversion, environmental monitoring, healthcare and communication and wireless network30. Although either big or small differences in polymer properties such as transmittance, flexibility, oxygen and water permeability, temperature resistance may largely impact on the functional properties desired for the respective applications. We chose thermoplastic transparent and flexible polymers, but not limited to, such as polyethylene terephthalate (PET), polyimide(PI), polycarbonate(PC), polyvinyl chloride(PVC), TOPAS (thermoplastic polymer mr-I T85) and CYTOP  as target substrates for graphene based conductive film which could open the new avenue either in the modern electronics. The fate of the stamping method depends on how strongly the adhesion of EVA coated graphene/Cu with target FTPs. Interestingly, we have found that the thin film of EVA coated on graphene/Cu can only bind strongly with the FTPs of less than 25 µm in thickness and lower glass transition temperature (Tg) value to the EVA without any pretreatment (unmodified-FTPs) while wide range of other FTPs such as higher or lower Tg to that of EVA with low thermal conductivity in thicker polymer substrates are considered upon surface engineering (surface engineered–FTPs) to enhance the binding strength between FTPs and EVA. What’s more, the electrical performance was investigated with triboelectric nanogenerators (TENG)34, which confirms that our transfer process is reliable for the different polymers and prospect for the development of flexible and transparent electronics.In this work, we designed a stamping method to transfer as grown graphene on Cu onto different flexible and transparent polymers (FTPs) which is applicable to the large scale graphene requirement as flexible and transparent electrode in modern electronics. This innovative method Figs  and S1 r−2 torr. Cu was allowed to be annealed for 60 minutes at 950 °C with a passage of 50 sccm of H2 gas maintain a tube pressure of 1 torr. Then 20 sccm methane, corresponding to a pressure of 2 torr, was introduced for 30 minutes to grow the continuous monolayer graphene.A commercially available Cu foil  was electrochemically polished in electrolyte solution composed of phosphoric acid and ethylene glycol(V/V = 3:1) with a bias of 2 V for 30 minutes. The electropolished Cu foils was washed thoroughly in alcohol and water sequentially to make sure the Cu surface was free from electrolytic residues. A monolayer graphene was grown on electropolished Cu in a low-pressure CVD system. Cu was loaded into the 4 inches diameter long tubular quartz at hot center of the furnace and degasses the furnace for the initial pressure of 7 × 1033 and dried in air.After CVD grown graphene on copper, an EVA solution  was coated onto the graphene side of the copper by spin/spray/blade coating process. Prior to coating process, Cu was flattened using glass rod; edges of the graphene/Cu were covered with scotch tape to avoid the coating of EVA onto the backside of the graphene/Cu. Spin coating is done with two spinning steps; 200 rpm for 30 seconds and 400 rpm for 60 seconds. Two times coating was done to ensure the continuity of the thin film EVA. In spray coating process, EVA solution was kept at hot container to make solution free flow through the nozzle. The spray nozzle movement and pressure were adjusted to 20 mm/s and 0.2 Mpa, respectively. We also demonstrated blade coating process, which is most suitable for the large scale graphene transfer attributed to roll to roll process. Speed of the blade movement was adjusted to 10 mm/s while distance between the blade and sample to be coated was set to 0.5 mm. The temperature of the sample holder both in spray and blade coating were kept at 50 °C to make fast evaporation of the solvent. After complete evaporation of solvent after being kept in dry box for 60 minutes, the resultant EVA/graphene/Cu was bound onto any of the flexible polymers (cleaned using isopropanol and blow-dried with a nitrogen gun) using hot lamination method to form FTP/EVA/graphene/Cu. Finally, graphene/EVA/FTPs is delaminated from the metal substrate by electrochemical hydrogen bubbling method2 was evaluated using a Raman spectroscope  with a laser excitation wavelength of 532 nm. Monochromatic Al X-ray  was used to analyze any metal residue remained after graphene being transferred onto FTPs. The transmittance measurement was examined using UV-Vis-NIR spectrophotometer . Contact angle measurement was done by contact angle tester (AST VCA Optima XE). Sheet resistance measurement was carried out using four probe system  with probe spacings of ~1 mm.The morphology was characterized by optical microscopy (Olympus BX51), scanning electron microscopy (ZEISS-Merlin) and atomic force microscopy (Bruker). Quality of the CVD grown graphene transferred onto Si/SiOg = −2000 V) and a high-voltage probe tip (VH = −6 kV). The device is driven by a mechanical shaker with controlled frequency and amplitude, where an accelerometer is used to monitor the acceleration during the measurement. The shaker is driven by an excitation signal generated from a signal generator  and a power amplifier .The final product from this transfer process graphene/EVA/FTPs film was used as the electrode of TENG. The fabricated device consists of a graphene/EVA/FTP electrode coated with CYTOP film (triboelectric layer) (18 × 20 mm) and a PET substrate coated with ITO films. Both two components were placed in an acrylic glass as a proof mass which can be driven by external vibration. The acrylic mass and transparent substrate were assembled in the elastic holder to make an arched structure with a dimension of 45 × 45 × 10 mm. The CYTOP polymer coated on the bottom plate is charged in a custom-built corona charging setup. The setup consists of a grounded electrode, a metal mesh grid   having similar Tg of EVA such as TOPAS, CYTOP, PET. 25 µm thin FTPs with lower Tg undergoes easy deformation at 120 °C, since as grown graphene on Cu has considerable roughness35, smoother FTPs adhered tighter with EVA/graphene/Cu due to roughness impression carried from graphene/Cu. But in the case of thicker FTPs of 100 µm such as PET, PC, PVC, we cannot found tight adhesion with EVA/graphene/Cu due to insufficient supply of required temperature to attain Tg value for thicker FTPs in lamination process. (iii) Delamination of FTP/EVA/graphene/Cu stacks to transfer graphene onto FTP/EVA from Cu substrate using electrochemical hydrogen bubble method by polarizing Cu/graphene/FTP at 2 V37 OM) Fig.  and scanOM) Fig.  of graphV37 Fig. . Figure 13. The innovation of our work relies on the thin film deposition of EVA onto as grown graphene on Cu and surface engineering of FTPs, where EVA acts as a binding agent between graphene and target substrates. In the process of coating, EVA solution preparation and optimization process is very important because we are the first using EVA to transfer graphene on to different FTPs. The preparation method is as follows: 1–4 wt.% EVA solution is made by dissolving EVA and stirring in cyclohexane at 75 °C. In fact, we demonstrated the coating method based on the sample size; spin coating is generally suitable for small size graphene since it is easier and makes the process fast. A thin layer of 1% EVA was spin coated twice to ensure a continuous layer, parameters were set similar to the PMMA coating38. On the other hand, for large area of graphene samples especially for roll to roll CVD graphene, either spray coating or blade coating process enables the process efficient and easier. Since the diameter of spray nozzle is small, 1% EVA is used in the spray coating method to avoid the blockage of nozzle. It should be noted that spray coating can control the tight contact of EVA with graphene upon adjusting the spray pressure to form the compact thin uniform EVA film. Multi spray coating deposition can also be done to control the thickness, which is attributed to achieve graphene transfer onto surface engineered polymers. To obtain thicker film on large area graphene, 4% EVA was coated by blade coating machine. By adjusting the distance between Cu/graphene and blade, thickness can be controlled up to 20 µm. Detailed procedure of coating method is described in experimental part. The samples after deposition were kept at room temperature for 60 minutes to evaporate the solvent. By comparing the vertical cross-sectional SEM images of Cu/graphene  FTPs are and blasted to make the surface rough with the formation of crest and trough in large scale. (ii) Fill the crest and trough by coating 1% EVA solution using various methods. Generally, graphene transfer is only valid onto smooth surface materials for electronic applications41. To transfer graphene onto a wide variety of FTPs having higher Tg value to that of EVA and low thermal conductivity in thicker polymer substrates, surface engineering is inevitable. EVA mediated transfer overcome the challenge to transfer graphene onto rough surface by providing smooth surface basement to graphene upon EVA coating onto the target rough surface polymers. Here, we used but not limited to PI as FTP target substrates to demonstrate graphene transfer onto the smooth surface with a higher Tg value to that of EVA. Graphene transfer from Cu/graphene/EVA stack onto the PI is unsuccessful, where arrow in the Fig. Interestingly, we found our EVA mediated stamping method of graphene transfer onto smooth FTPs can only be realized when their thickness and Tg is less than 25 µm and ~140 °C, respectively. Weak binding force between the two smooth surface polymers films were noticed in the fabrication of graphene/metal nanowire transparent electrodes16  and a high-voltage probe tip (VH = −5 kV). After charging for 15 min, the surface potential of the electrets layer is mapped in Fig. 2 at 46 Hz. To find the optimal work frequency, we have explored the relationship between the output power of the TENG and the frequency of the vibration source under different amplitudes, as shown in Fig. 47. Furthermore, it is observed that the electric signal also can be generated by hand driving periodically; the output result of device FTP/EVA/graphene/CYTOP VS ITO/PET was shown in Fig. To confirm the graphene transfer performance on the electrical conductivity and flexibility, we have applied graphene/EVA/FTPs electrodes in the TENG. The fabricated device consists of a FTPs/EVA/graphene electrode coated with CYTOP film (18 × 20 mm2) and a PET substrate coated with ITO films sketched in Fig. tup Fig. . The set24.We have demonstrated a stamping method to transfer graphene onto different FTPs using EVA as binder only between graphene and target substrates without affecting the Cu substrates which could be used for repeated graphene growth. Surface modification of FTPs to alter the effective surface interaction with the EVA widens the choice for target substrates. Our transfer method is simple and fast, which ensures the clean and efficient transfer without inducing any damage either onto the graphene/substrates or Cu foil. What’s more, the electrical output performance is demonstrated with the fabrication of TENG and implied that our transfer method is realistic to scale up the graphene on plastics for industrial-scale. We believe this approach may be further improved by adopting effective strategies like metal nanowire based graphene transparent and flexible electrode reported elsewhere to replace ITO in optoelectronic devicesSupplimentary - Revised