Currently, there are two antifibrotics used to treat idiopathic pulmonary fibrosis (IPF): pirfenidone and nintedanib. Antifibrotics slow disease progression by reducing the annual decline of forced vital capacity (FVC), which possibly improves outcomes in IPF patients. During treatment, patients occasionally switch antifibrotic treatments. However, prognostic implication of changing antifibrotics has not yet been evaluated.This multi-center retrospective cohort study examined 262 consecutive IPF patients who received antifibrotic therapy. Antifibrotic agents were switched in 37 patients (14.1%). The prognoses were compared between the patient cohort that switched antifibrotics (Switch-IPF) and those without (Non-Switch-IPF) using propensity-score matched analyses.p < 0.0001). In propensity-score matched analyses that were adjusted to age, sex, FVC (%), history of acute exacerbation, and usage of long-term oxygen therapy, the Switch-IPF cohort had significantly longer survival times than the Non-Switch-IPF group . The second-line antifibrotic therapy showed similar survival probabilities than those in first-line antifibrotic therapy in multistate model analyses.The median period between the initiation of antifibrotic therapy and the drug switch was 25.8 (12.7–35.3) months. The most common reasons for the switch were disease progression (n = 17) followed by gastrointestinal disorders (n = 12). Of the 37 patients that switched antifibrotics, only eight patients disrupted switched antifibrotics by their adverse reactions. The overall prognosis of the Switch-IPF cohort was significantly better than the Non-Switch-IPF cohort (median periods: 67.2 vs. 27.1 months, Switching antifibrotics is feasible and may improve prognosis in patients with IPF. A further prospective study will be required to confirm clinical implication of switching the antifibrotics.The online version contains supplementary material available at 10.1186/s12890-021-01587-3. Switching antifibrotics were generally well-tolerated. The prognosis of IPF patients switching antifibrotics was significantly better than those not switching, suggesting that switching is feasible and may improve prognosis in patients with IPF.Idiopathic pulmonary fibrosis (IPF) is a progressive fibrosing form of interstitial lung disease (ILD) with unknown aetiology –3. IPF iThese two antifibrotics have distinct types of antifibrotic mechanisms  and diffThis retrospective study was conducted on 312 consecutive patients with ILD, receiving pirfenidone or nintedanib, at Hamamatsu University of School of Medicine, Seirei Hamamatsu Hospital, and Seirei Mikatahara Hospital. All patients were treated between February 2009 and March 2020. Fifty ILD patients were excluded from the study: 37 patients were diagnosed with non-IPF ILD, and 13 IPF patients had insufficient clinical data. Thus, this study enrolled 262 patients with IPF. The IPF patients switching antifibrotics (Switch-IPF) was defined as patients who received first-line antifibrotics more than one month and followed by second-line antifibrotic therapy. The IPF patients who received first-line antifibrotics less than one months or were not treated with second-line antifibrotics were defined as Non-Switch-IPF. Diagnosis of IPF was based on the ATS/ERS/Japanese Respiratory Society (JRS)/Latin American Thoracic Association (ALAT) criteria . The Mann–Whitney U test was used to compare the continuous variables. Fisher’s Exact test for independence was used to compare categorical variables. Overall survival time was measured from the start date of first-line antifibrotic therapy, unless otherwise specified. Propensity-matched analyses were employed to determine the impact of switching the antifibrotics on prognosis. Propensity score matching was performed using the following algorithm: 1:1 optional match with a ± 0.05 calliper and no replacement. Univariate and multivariate analyses were also performed using the Cox proportional hazards regression model. The variables of propensity score matching and multivariate Cox-regression analyses that were considered clinically important, and specific risk factors for mortality in IPF were selected , 18–20.As “switching antifibrotics” was a time-varying event, the values of “switching antifibrotics” was evaluated using time-dependent Cox regression analysis and Markov multistate model to describe the clinical transitions of second-line antifibrotic therapy –23. CumuAs “switching antifibrotics” was a time-varying event, we evaluated the values of “switching antifibrotics” by time-dependent Cox regression analysis and Markov multistate model to describe the clinical transitions of second-line antifibrotic therapy. The Markov multistate models have traditionally been used to study effect of transitory state of illness (or interventions such as transplantation) on prognoses to death –23. The p values < 0.05 were considered statistically significant.Statistical analyses were performed using GraphPad Prism Version 6 , JMP , and R software version 4.0.2 . All analyses were two-tailed and The clinical characteristics at the initiations of first-line antifibrotics of IPF patients with Switch-IPF) and Non-Switch-IPF are shown in Table Among Non-Switch-IPF cohort, 48 patients 21.3%) discontinued the antifibrotics during the observation period with a median exposure time of 7.2 months. The characteritics of Non-Switch-IPF Continued cases and Discontinued cases were also presented in Table .3% discoAmong the Switch-IPF patients, the most common cause of switching the antifibrotics was disease progression , followed by GI side effects n = 12)  months vs. 5.3 (0–15.8) months, respectively, p < 0.0001]. Patients who switched antifibrotics due to Non-PD, mostly due to adverse drug reactions (ADRs), were initiated second-line treatment delayed from after resolutions of ADRs.The detailed time course and reasons for switching antifibrotics are shown in Fig. The declines of FVC (%) and FVC (L) between the first and second-line treatments are shown in Fig. The clinical characteristics at the initiations of second-line antifibrotics were showed in Additional file During the observation period, 17 patients in the Switch-IPF cohort and 130 patients in the Non-Switch-IPF cohort died. The most common cause of death was chronic respiratory failure, followed by AE. The causes of death did not differ between the Switch-IPF and Non- Switch-IPF patients Table : Fig. S2p = 0.0219, Fig. As shown in Table Not all Non-Switch-IPF patients received antifibrotics for the entire duration of the study; 48 patients (21.3%) discontinued antifibrotic treatment during the observation period, whereas the rest patients (n = 177) were continued first-line antifibrotic therapy. We therefore compared the survival times of Switch-IPF patients with Non-Switch-IPF Discontinued cases and Non-Switch-IPF Continued cases, respectively. The Switch-IPF patients still exhibited significantly longer survival times than Non-Switch-IPF Discontinued cases or Non-Switch-IPF Continued cases  had a significantly longer survival than those not (Non-Switch-IPF), and this survival benefit remained significant in propensity-matched analysis adjusted by age, sex, FVC (%), AE history and LTOT usages. Further, second-line antifibrotic therapy showed similar survival probabilities than those in first-line antifibrotic therapy using a multistate model analyses. These results suggested that the switch of antifibrotics is feasible and may have a prognostic benefit in patients with IPF.Currently, the antifibrotic medications, pirfenidone and nintedanib, are available for the treatment of IPF. Nintedanib inhibits multiple tyrosine kinases, including the receptors for vascular endothelial growth factor, fibroblast growth factor, and platelet-derived growth factor. The underlying mechanism of action for pirfenidone is still unknown , but it The most common reason for the switch was disease progression (45.9%), followed by GI side effects (32.4%) as determined by physicians. Compared to patients in the Switch-IPF group who switched for other reasons (Switch-IPF due to non-PD), the patients who switched due to disease progression (Switch-IPF due to PD) had significantly longer exposure periods to the first-line antifibrotics as well as shorter intervals from the end of first-line therapy to the start of second-line therapy. This is likely because the Switch-IPF due to non-PD patients mostly discontinued first-line antifibrotics due to ADRs within a short exposure periods from the initiation of first-line antifibrotics. Regarding the feasibility of second-line antifibrotics, among the 37 Switch-IPF patients, only eight (21.6%) discontinued second-line antifibrotics. None of the Switch-IPF due to PD patients had severe ADRs that caused them to discontinue second-line antifibrotics. By contrast, eight out of 20 Switch-IPF due to non-PD patients discontinued second-line antifibrotics because of ADRs. In particular, three patients terminated both first and second-line antifibrotics due to GI side effects. These issues are consistent with chemotherapy-induced nausea and vomiting (CNVI). In the field of oncology, experienced CNVI once was identified as a futured risk factor of CNVI in further chemotherapy . These dAlthough the causes of death did not significantly differ between Switch-IPF and Non-Switch-IPF patients, the survival times of Switch-IPF patients were significantly longer than those of Non-Switch-IPF patients. However, the baseline characteristics of Switch-IPF patients were not identical to those of Non-Switch-IPF patients. For instance, Switch-IPF patients had preserved lung function, lower incidences of AE history, and lower frequencies of LTOT usage compared with Non-Switch-IPF patients. Thus, we employed propensity score-matched analysis and multivariate Cox proportional analysis to adjust for these baseline differences. The propensity analysis adjusted by age, sex, FVC (%), AE history, and LTOT usages revealed that Switch-IPF patients still demonstrated significantly longer survival times than Non-Switch-IPF patients. Furthermore, the multivariate Cox proportional analysis revealed that patients with IPF who switched antifibrotics were identified as a population with better prognoses. Because 48 Non-Switch-IPF patients (21.3%) discontinued antifibrotic treatment during the observation period, we compared the prognoses between the Switch-IPF patients with Non-Switch-IPF Discontinued cases and Non-Switch-IPF Discontinued cases, respectively. We found that Switch-IPF patients still demonstrated significantly longer survival times than Non-Switch-IPF Discontinued cases and Non-Switch-IPF Discontinued cases. Collectively, these results suggest that switching antifibrotics from one to another may improve the prognosis among patients discontinuing first-line antifibrotics due to ADRs or those showing disease progression despite treatment.The rationale for the longer survival times of the Switch-IPF patients compared to the Non-Switch IPF patients is not entirely clear. In the time-dependent Cox proportional analysis, “switching antifibrotics” itself did not show great impact to change prognosis of IPF, but efficacies of second-line therapy was not inferior to those of first-line therapy by the multistate model analyses Fig. , suggestThe present study had several limitations. Although the present study showed that patients with IPF who switched antifibrotics as a population with better prognosis, the prognostic implications of switching the antifibrotics were not completely clarified even evaluated using time dependent Cox proportional model and multistate model. Second, this study was retrospective and the sample size was not large enough to provide conclusive results. Furthermore, because pirfenidone was approved before nintedanib, most of the patients switched from pirfenidone to nintedanib rather than the other way around. The disease behavior, such as a decline in FVC (%) before and after antifibrotic therapy, was not evaluated. Additionally, the decision to switching antifibrotics either due to disease progression or ADRs is subjective, and there were no formulated protocols used by physicians. Collectively, these limitations may cause potential biases in this study. However, this study may provide novel clue about the sequential usage of two antifibrotics. These findings are important because only two antifibrotics are currently available, and neither drug completely halts disease progression. Thus, balanced and large-scale prospective studies are required to overcome these limitations.In conclusion, the present retrospective study showed that 37 out of the 262 IPF patients who had received antifibrotics switched drugs during the observation period, and the second-line antifibrotics were generally well-tolerated. Moreover, patients with antifibrotics were identified as a population with better clinical outcomes as assessed by propensity-matched and multivariate Cox proportional analyses. Additionally, the present study showed survival benefit of second-line antifibrotic therapy was not inferior to that of first-line therapy Despite several limitations, the results of our study suggest that switching antifibrotics may be beneficial for the clinical management of IPF, especially among IPF patients discontinuing first-line antifibrotics due to ADRs or disease progression.Additional file 1: Figure S1. Survivals of patients with IPF with or without switching antifibrotics stratified by GAP system: Switched cases vs. Non-switched cases. Survival of patients with IPF GAP stage I with or without antifibrotic switching (A). Survival of patients with IPF GAP stage I with or without antifibrotic switching (B). p values were determined by the log-rank test. Cumulative survival probabilities from initiation of antifibrotic therapy were calculated. An event was defined as death from any cause and patients who were lost or still alive were censored at the last follow-up date.Additional file 2: Figure S2. Survival of patients with IPF switching antifibrotics as analyzed by antifibrotic medication or cause of switching. Survival of patients with IPF switching antifibrotics by antifibrotic medication (A), and causes of switching (B). p values were determined by the log-rank test. Cumulative survival probabilities from initiation of antifibrotic therapy were calculated. An event was defined as death from any cause and patients who were lost or still alive were censored at the last follow-up date.Additional file 3:Supplementary Table 1. Reasons for discontinuation of antifibrotics in 48 patients with Non-Switched IPF. Supplementary Table 2. Timeline of switching antifibrotics. Supplementary Table 3. Differences between the clinical characteristics in first-line and second-line anti-fibrotic therapy. Supplementary Table 4. Propensity-matched 74 patients with IPF with or without switches of the antifibrotics.


The application of polymer inclusion membranes (PIMs) for the aquatic remediation of several heavy metals, dyes, and nutrients has been extensively studied. However, its application in treating organic compounds such as Ibuprofen, an emerging pharmaceutical contaminant that poses potential environmental problems, has not been explored satisfactorily. Therefore, graphene oxide (GO) doped PIMs were fabricated, characterized, and applied to extract aqueous Ibuprofen at varied pH conditions. The doped PIMs were synthesized using a low concentration of Aliquat 336 as carrier and 0, 0.15, 0.45, and 0.75% GO as nanoparticles in polyvinyl chloride (PVC) base polymer without adding any plasticizer. The synthesized PIM was characterized by SEM, FTIR, physical, and chemical stability. The GO doped PIM was well plasticized and had an optimal Ibuprofen extraction efficiency of about 84% at pH of 10 and 0.75% GO concentration. Furthermore, the GO doped PIM’s chemical stability indicates better stability in acidic solution than in the alkaline solution. This study demonstrates that the graphene oxide-doped PIM significantly enhanced the extraction of Ibuprofen at a low concentration. However, further research is required to improve its stability and efficiency for the remediation of the ubiquitous Ibuprofen in the aquatic environment. A composite material consists of two or more components designated as matrix and filler. The primary function of the filler is to fill in the matrix and synergistically combine the advanced properties of the matrix and filler for improved performance, as evidenced by the several significant breakthroughs and considerable benefits for commercial water treatment and desalination applications . Over th−1 at ordinary temperature, high thermal conductivity of ~5000 W m K−1, enhanced active sites, large delocalized π-electron systems, and chemical stability coupled with an exclusive tunable size structure. Hence, the material can be easily engineered for different aqueous filtration techniques. Furthermore, graphene is an ideal adsorbent for wastewater making it a unique nanofiller material [Following its discovery by Novoselov et al. in 2004, graphene, a single-layer 2-D structure material with thin thickness at the atomic level, has received serious attention in the broad scientific community and is notably recognized as a major potential component in next-generation membrane technologies , ,16,17,18material ,18.Native graphene is hydrophobic, which limits its application in wastewater treatment processes. However, the oxidized form of graphene (GO), formed from thermal or chemical exfoliation of graphite oxide, exhibits hydrophilic properties and is frequently used as nanofillers for water remediation mechanisms. Furthermore, the presence of oxygenated functional groups such as the carboxyl, the primary hydroxyl group on edge plane, epoxy, tertiary hydroxyl, and carbonyl groups on basal planes, among others found in GO, coupled with their excellent solubility and the potential for surface functionalization, make GO a better nanocomposite material compared to the native graphene. In addition, previous reports have proven the remarkable removal response of magnetic/graphene nanoparticles or GO composites for contaminants such as chromium, copper, arsenic, cadmium, lead, cobalt, and an organic dye .The advent of new and more sensitive analysis methods has made it possible to detect very low concentrations of various potentially dangerous contaminants in the aquatic systems up to ng/L detection level. This newly detected and potentially harmful chemical class is now globally classified as “emerging pollutants” or Contaminants of Emerging Concern (CECs). According to Poynton and Robinson, the US Geological Survey 2016) has defined CECs as “any unregulated synthetic or naturally occurring chemical or any microorganism not commonly assessed in the environment but with the potential of been dispersed in the environment causing known or suspected adverse ecological and (or) human health effects 16 has de,22,23.Pharmaceutical and related compounds, otherwise known as active pharmaceutical ingredients (APIs), are now considered emerging environmental contaminants. Such a wide range of emerging pharmaceutical contaminants found in wastewater include analgesics and anti-inflammatory drugs , Anti-ulcer agents (Ranitidine), Psychiatric drugs (Paroxetine), Antiepileptic drugs (Carbamazepine), Antibiotics , B-blockers , Diuretics (Hydrochlorothiazide), Hypoglycaemic agents (Glibenclamide), lipid regulator, and cholesterol-lowering statin drugs  ,27,28,29Therefore, the concentration and toxicity of Ibuprofen in wastewater treatment plants and water bodies are a growing concern. According to Marchlewicz et al., the increasing Ibuprofen pollutant in the aquatic environment poses a potential hazardous impact due to its bioactive nature and ubiquitous presence in surface water, rivers and lakes, hospital, and municipal water, and probably in drinking water. Unfortunately, conventional water treatment cannot eliminate Ibuprofen efficiently ,30,31.Polymer inclusion membranes (PIMs) have been widely studied and reported to be efficient in removing dyes, heavy metals, and nutrients from aquatic systems. However, only a few studies have investigated the removal of aqueous Ibuprofen using PIM. Hence, this study evaluates the stability and potential of functionalized polymer inclusion membrane to remove low concentration Ibuprofen, which prolonged accumulation has been recognized as a pharmaceutical’s endocrine disruptors in the aquatic system ,36,37,38® 336 TG obtained from Alfa Aesar Thermofisher Scientific  as ionic exchange carrier. The reagents used include 0.1M Hydrochloric acid  and 0.1 M Sodium hydroxide. All reagents employed are of standard analytical quality.Ibuprofen, IBP (purity ≥ 99.0%)  without further purification, was used to simulate IBP aqueous pollutant model. Poly(vinyl chloride) (Mw~43000) as Polymers, Tetrahydrofuran (THF) (99.9%)  as solvent was purchased from Sigma–Aldrich, Graphene (OH) (multi-layered) (Purity: 99.99%) of lateral Size: 10 μm (India) as nanoparticles and AliquatPolymer (PVC) was dissolved in THF solvent and stirred to form a homogenous dope solution at 65 °C. The pristine (PIM GOO) was fabricated without adding carrier or graphene oxide. The same step was followed to fabricate the control PIM (PIM GO) but with an Aliquat carrier (Formulation according to Polymer (PVC), Aliquat 336 carrier, and an appropriate varied amount of graphene oxide were dissolved in THF (according to The surface morphology of the PIMs was observed by scanning electron microscopy (SEM) HITACHI (TM3000) Tokyo, Japan, at 5 kv and ×100 magnification. The membrane samples were initially gold-plated using Quorum SC7620 . −1.Fourier transform–infrared spectroscopy (FT–IR) measurements were performed on the fabricated and tested PIMs. The test was conducted to identify the interrelations among the PVC polymer, aliquat 336 carrier, and the GO nanofiller . TherefoPhysical stability is one of the most significant characteristics of a PIM. A physically stable PIMs should be able to bend without tearing or visible deformation, signaling an excellent physical strength . TherefooW is the initial weight of the PIM, and tW is the final PIM’s constant weight after drying.The chemical stability of the polymer inclusion membrane, particularly in environmental conditions of interest, is a critical factor for PIM’s practical application in water remediation. The loss of carrier during application attributed to the weight loss of the PIM after being subjected to specific environmental conditions is a helpful tool to assess the membrane’s chemical stability ,41,42,432 and clamped between two 250 mL identical diffusion cells on a Teflon ring-shaped support , control PIM (GO), and graphene oxide doped PIMs (G1-G3) is detected at the spectrum bands of 684, 685, and 686 cm957 cm−1 ,51,52.−1 [−1, indicating the CN group, which is unique to the Aliquat-336, confirming the physical integration of the Aliquat carrier within the PIMs’ matrix.The control PIM GO and the graphene doped PIMs G1–G3 distinctly revealed the Aliquat carrier added to them without any significant modification in the polymer chain of the PVC polymer. The quaternary amine group (CH2–N and CH3–N) of the Aliquat 336 carrier showed a peak at 2850 cm−1 ,53. A ne−1 [−1 represent the O-H stretching vibration of hydroxyl groups, while the peak of 1630 cm−1 is the C=O unit of -COOH groups stretch band of graphene oxide [The presence of graphene oxide in PIMs’ G1–G3 can be observed by the ring structure of the GO as indicated by the peak at 2160 cm−1 ,55. Simine oxide ,57.−1, recognized as stretching C=C, indicates the Ibuprofen complex on the graphene oxide-doped PIM [−1 and 2160 cm−1 representing the ring structure of the GO are no longer seen, indicating a likely loss of the nanoparticles due to leaching occasioned by the instability of nanoparticle engrafted membranes [To evaluate the mechanism of Ibuprofen removal by the optimum graphene doped PIM and at the optimum pH, a comparative infrared spectrum of PIM G3 before and after Ibuprofen extraction was investigated, as shown in oped PIM ,58. The PIMs are usually considered physically stable when bent without tearing or visibly deforming the thin membrane structure. The results of the physical stability assessment to determine the effect of incorporated GO nanoparticles on the transparency and flexibility of the fabricated PIMs are presented in A critical and well-known drawback of PIM is its chemical instability due to leaching out of the carrier from the membrane into the aqueous solution. The rate of mass loss of the membrane under a specific condition, such as the pH of the media and membrane constituents, is strongly related to the loss of efficiency of the membrane during application ,61. The The effect of the different amounts of GO added to the doped PIMs  compared with the pristine PIM was evaluated using 10 mg/L aqueous Ibuprofen extraction performance. Additionally, the effect of pH of the feed solution was also assessed using the optimal PIM.The results of the efficiency of Ibuprofen extraction using the fabricated PIMs are as shown in To investigate the effect of pH on the removal efficiency of Ibuprofen, the pH of the feeding solution was adjusted to 2, 6, and 10 . It is wThe effect of GO enhanced PIM by incorporating a small amount of GO as nanoparticle and Aliquat carrier on the remediation of trace Ibuprofen  and membrane stability was successfully studied. The fabricated GO-doped PIM was more stable in acidic and neutral media than in the alkaline medium. Furthermore, the optimum extraction efficiency of ~84% obtained indicates a high potential for Ibuprofen extraction using GO doped PIM. However, further research is required to improve the stability of the GO doped PIM and to study the effect of other operating conditions, such as the feed concentration and receiving phase types.


In consideration of the presented optical-thermally excited resonant mass detection scheme, molecular dynamics calculations are performed to investigate the thermal actuation and resonant mass sensing mechanism. The simulation results indicate that an extremely high temperature exists in a 6% central area of the graphene sheet exposed to the exciting laser. Therefore, constraining the laser driving power and enlarging the laser spot radius are essential to weaken the overheating in the middle of the graphene sheet, thus avoiding being burned through. Moreover, molecular dynamics calculations demonstrate a mass sensitivity of 214 kHz/zg for the graphene resonator with a pre-stress of 1 GPa. However, the adsorbed mass would degrade the resonant quality factor from 236 to 193. In comparison, the sensitivity and quality factor could rise by 1.3 and 4 times, respectively, for the graphene sheet with a pre-stress of 5 GPa, thus revealing the availability of enlarging pre-stress for better mass sensing performance. Graphene-based nanoelectromechanical systems (NEMS) offer rich prospects for delicate sensing applications, including accelerometers , biomedi−21 g) and yoctogram (10−24 g) mass, respectively [Before the advent of graphene resonators, SiC and carbon nanotubes were used as resonators for mass sensing, with the resolutions of zeptogram  and the surface of graphene membrane suspended on the ferrule (rI2), respectively, were sent to the filter through the circulator. The actuation laser was filtered, while the detection laser was captured by a photodetector (PD) with a bandwidth of 200 MHz, and the converted electrical signal was processed by the lock-in amplifier and shown on screen.The presented resonant mass sensor was based on the adsorbates induced frequency shifts of graphene resonators. L, thus changing the interferometer intensity of the two reflected beams of rI1 and rI2, as noted in The intensity of the actuation laser was modulated by a signal swept from 1 MHz to 5 MHz, as shown in Molecular dynamics simulations ,29,30 ha5, which far exceeds most relevant MD simulations that have been reported [The modeling schematic diagram of a peripherally clamped circular graphene sheet is shown in reported ,33,34,35reported ,37,38, areported  was consQ is the amount of heat added per atom; iE is kinetic energy for atom i; i,tv is the velocity of atom i at time t, and i,tv+1 is the corresponding velocity at the next step. Correspondingly, the atoms in the heat drain area had updated velocities, as followsWe used a non-equilibrium MD (NEMD) calculation to study the thermal effect of graphene when exposed to an actuation laser. The laser spot was located at the center of the graphene sheets, which served as the heat source, as shown in t is the temperature; Bk is the Boltzmann constant; m is the atom mass, and rmsv is the square root of the mean square of the atom velocities.After the heat flow from the center to boundary had attained a steady state, the velocities of every atom were recorded, and the temperature distribution was induced from the atom velocities averaged over time and space according tor is the distance to the middle; D is the diameter of graphene, and v0 is set to 1 Å/ps, which is small enough to ensure linear flexural oscillation [To actuate the oscillation of the graphene sheet in MD calculation, a cosinoidal initial velocity profile along the radius was employed, which can be described asillation . When thillation  expresse2O was 0.047 eV [ε in Equation (5), and the zero-crossing distance σ for the potential was set to 3.16 Å. Under this potential, water molecules were attached to the surface of graphene as depicted in The first-principles study revealed that the adsorption energy between graphene and H0.047 eV ,42,43, wQ refers to the local heat flux; κ is the thermal conductivity; dT/dr is the temperature gradient; r is the radius to the center; h is the graphene sheet height, and 2πrh represents the cross-sectional area of heat flow. After the heat flow has reached a steady state, the velocities of every atom are recorded, the equivalent temperature of every atom is obtained using Equation (3), and the results are depicted in Vibrations of the circular graphene resonators are actuated by the laser spot. MD calculation is performed to study the actual temperature distribution of the graphene sheet with a radius of 625 Å when exposed to a laser, and the laser spot, with a radius of 50 Å, is opposite to the middle of the graphene. This middle area is a heat source, while the boundary of the graphene adheres to the zirconia ferrule substrate, serving as the heat drain. In this case, heat flows outward from the interior obeying Fourier’s law:r TT0 are the temperatures at position r and r0, and other parameters are the same as Equation (6). Since the max heat radius is 150 Å, the temperature at this position is chosen as the reference temperature T0, and fitting curves match the MD calculation results quite well with an R-square of 0.99 as shown in To figure out the exact temperature distribution along the radius, the circular graphene sheet is divided into 50 chunks along the radius, and the temperatures of every chunk are shown in 3. In the center, a peripherally circular graphene sheet with a diameter of 125 nm starts vibrating, and the average out-of-plane displacements are calculated, as shown in After the thermally excited graphene sheet starts vibrating, the positions and velocities of every atom are calculated, and the corresponding mechanical frequencies are obtained by Fourier transform. To investigate the effect of adsorbates on frequency shift, a mass of water molecules is put in the simulation box. The average spacing of water molecules can be deduced by the concentration of water vapor, and we can change the spacing of water molecules to represent different humidity. The relationship between average water molecule spacing and humidity at 20 °C is shown in detail in m is the adsorbate mass; m0 is the graphene mass, and f0 is the eigenfrequency of the graphene sheet, which is directly proportional to the square root of the tension of graphene, expressed asr is the radium; σ refers to the tension; and ρ is the density of graphene sheet. Based on this, a linear function is adopted to fit the MD dots, and the fitting results show that the slope is about 0.065, with an R-square of about 0.94. Since there are 468,552 carbon atoms in the suspended part of the graphene sheet, m0 in Equation (8) is about 9340 zeptograms. When the relative humidity rises from 0 to 100% at 20 °C, the mass of the total adsorbed water molecules is estimated to be 281 zeptograms. In this case, the mass sensitivity is calculated to be 214 kHz/zg. In consideration of the fact that the size of the MD model is one-thousandth of that of the real sensor, the actual sensitivity is estimated to be 214 Hz/zg, according to Equations (8) and (9).In this investigation, values of relative humidity of 0%, 20%, 40%, 60%, 80%, and 100% at 20 °C are considered. On the other hand, the adsorbates would substantially degrade the quality factor of the graphene sheet, as shown in A scheme for an optical-thermally excited resonant mass detector is presented, and molecular dynamics calculations are performed to investigate the thermal actuation and resonant mass sensing mechanism. For the peripherally clamped circular graphene with a diameter of 125 nm , MD results demonstrate that the maximum temperature of graphene exposed to the actuation laser is proportional to the laser power and inversely proportional to the laser spot radius. Typically, the temperature of the middle of the graphene reaches 527 K if the power of the actuation laser is 100 eV/ps and the spot radius is 50 Å. The high temperature occurs in the central 6% of the area, and in practice is extremely likely to burn through the graphene sheet. To avoid this, the power of the actuation laser should be controlled to within 20 eV/ps, or the actuation spot radius should be enlarged to 100 Å. In addition, when the graphene is actuated to vibrate, MD results show that the resonant frequency is 4.31 GHz for the graphene resonator with a pre-stress of 1 GPa, and the mass sensitivity is calculated to be 214 kHz/zg. Meanwhile, MD results reveal that the adsorption of water molecules degrades the quality factor quite a lot, from 236 to 193. However, stronger pre-stress could effectively improve both the mass sensitivity and the resonant quality factor, which increased by up to 1.3 and 4 times, respectively, for a graphene sheet with a pre-stress of 5 GPa.


Intestinal homeostasis is highly dependent on the proliferation and differentiation of intestinal epithelial cells (IEC). IEC arise from intestinal stem cells (ISCs) that reside at the bottom of intestinal crypts. Following proliferation, the IEC migrate up as transient amplifying (TA) cells, and differentiate into mature IEC subtypes. When this process is disrupted, it can lead to aberrant IEC proliferation and differentiation. Mucus production by secretory goblet cells is also crucial for intestinal homeostasis, as mucus separates the IEC from luminal microbiota. Surprisingly, mice lacking Muc2, the main protein component of mucus, display increased distal colonic IEC proliferation and crypt hyperplasia at baseline, suggesting a relationship between Muc2 production and IEC proliferation.We investigated how mucus production impacts IEC proliferation and differentiation in the intestinal crypt.+/+) and Muc2 deficient (Muc2-/-) littermates to measure distal colon crypt length and IEC proliferation pattern via microscopy. Organoids were also derived from distal colons of Muc2+/+ and Muc2-/- mice, and quantified for size, density and proliferation for 7 days to test whether the hyper-proliferation phenotype was also seen in vitro, thus epithelial-intrinsic. Crypts and organoids were collected for RNA sequencing to examine changes in IEC proliferation pathways. Proliferation assessments were repeated in germ-free (GF) Muc2+/+ and Muc2-/- mice. Muc2-/- mice were also cross-bred with Lgr5-EGFP-IRES-CreERT2 mice to investigate the contribution of ISCs to IEC hyperproliferation resulting from Muc2 deficiency.We used wildtype (Muc2-/- mice in concert with a > twofold increase in Ki67+ TA cells as compared to Muc2+/+ mice. Similarly, Muc2-/- organoids also displayed significantly greater size, density and an increased number of Ki67+ cells than Muc2+/+ organoids. Hyperproliferation was also seen in GF mice and organoids, suggesting that mucus impacts IEC proliferation independent of the microbiome. Muc2-/- Lgr5-EGFP+ mice showed no significant increase in numbers of Lgr5+ cells, indicating that Muc2 deficiency does not directly impact ISC number, but rather their proliferation and differentiation reflected in increased numbers of TA cells. RNA-sequencing results suggested that changes in lipid metabolism may underlie the increased IEC proliferation seen in Muc2-/- mice.Significant crypt hyperplasia was observed in the distal colons of Muc2Mucus not only promotes IEC homeostasis by separating luminal bacteria from the intestinal epithelium, but also intrinsically modifies IEC proliferation independent of the microbiota. Taken together, our results emphasize the importance of mucus in controlling gut health through mechanisms independent of its role in barrier function.CCC, CIHRC.H.I.L.D Foundation


Only a select few L1 loci in the human genome are expressed in any given cell line or organ, likely to minimize damage done to the genome. The epigenetic features and requirements of expressed L1 loci are currently unknown. Using human cells and comprehensive epigenetic analysis of individual expressed and unexpressed L1 loci, we determined that endogenous L1 transcription depends on a combination of epigenetic factors, including open chromatin, activating histone modifications, and hypomethylation at the L1 promoter. We demonstrate that the L1 promoter seems to require interaction with enhancer elements for optimal function. We utilize epigenetic context to predict the expression status of L1Hs loci that are poorly mappable with RNA-Seq. Our analysis identified a population of ‘transitional’ L1 loci that likely have greater potential to be activated during the epigenetic dysregulation seen in tumors and during aging because they are the most responsive to targeted CRISPR-mediated delivery of trans-activating domains. We demonstrate that an engineered increase in endogenous L1 mRNA expression increases Alu mobilization. Overall, our findings present the first global and comprehensive analysis of epigenetic status of individual L1 loci based on their expression status and demonstrate the importance of epigenetic context for L1 expression heterogeneity. Retrotransposons are mobile elements that have colonized the human genome for tens of millions of years . These eIn order to create a new copy, a full-length L1 element is first transcribed into L1 mRNA which is then exported to the cytoplasm . The L1 in vivo because only different small sets of L1 loci are expressed in each organ  traces website. HeLa cell line fastq files are the same files used as the negative control of Figure Cytoplasmic, polyA selected, strand-specific Illumina RNA-Seq 2 × 100 bp) as previously described ,88 was u0 bp as pATAC library preparation and PE sequencing were done by the Tulane Center for Translational Research in Infection and Inflammation NextGen Sequencing core according to their standard protocols seeding 2 million cells. Sequencing reads were mapped using BOWTIE as described for the RNA-Seq data ,88 and bBedtools INTERSECT was used to determine whether each L1 locus overlapped with a gene. Gene coordinates for hg19 were downloaded from the UCSC genome browser .Analysis of activating histone marks associating with individual L1 loci was carried out using bed files downloaded from ENCODE (see below) for each of the CHIP-Seq experiments for activating histone marks. Bedtools INTERSECT was used to identify overlaps between the peaks from the CHIP-Seq and the 5′ end of the full-length L1 annotations. An individual locus is positive for a certain histone mark if the peak overlaps within 500 bp upstream and 300 bp downstream of the L1 5′UTR start site.https://figshare.com/articles/All_CpG_sites_for_hg19/1415416/1.Whole Genome Bisulfite Sequencing (WGBS) using 100 bp paired-end reads was carried out by BGI Global Genomic Services using a DNBseq platform. Bismark-0.20.1  and BOWTPromoter motifs were analyzed based on the canonical motif sequences. The YY1 motif ‘AGCCAAGATGGCCGAATAG’ and RUNX3 motif ‘TGCATTTCCATCTGAGGTA’ used for alignment were derived from the consensus active L1 element . All nuchttp://3dgenome.fsm.northwestern.edu/chiapet.php. CTCF and Pol II loops were identified with Chromatin Interaction Analysis by Paired-End Tag Sequencing (ChIA-PET)  . Analysihttp://www.repeatmasker.org/) analyzed in this manuscript and identified the 246 L1Hs loci present in MCF7 cells analyzed in Figure Paired-end whole genome sequencing of MCF7 cells was obtained from NCBI SRA accession number SRR8652105. The paired alignment files were aligned separately to the human L1 consensus sequence using STAR v2.3.0e and allowing one alignment per read (–outFilterMultimapNmax 1) and a maximum of 25 mismatches (-outFilterMismatchNmax 25). Alignments that occurred in the first 700 bp of the L1 consensus sequence and aligned in the reverse orientation to L1 were extracted. These reads were then used to find their pair based on matching read IDs. The opposite read pair was then aligned to the human genome (hg38) using BOWTIE v0.12.8, requiring unique alignments (-m 1) and allowing three mismatches (-v 3). Alignments in the resulting file were then parsed for read alignments that occurred within the 5′ upstream region of annotated L1Hs loci in hg38. This was done using Bedtools v2.22.0. We cross-referenced the loci detected in MCF7 cells using this method with the 4973 L1 elements from the REPEATMASKER annotation  (HeLa cells were cultured in MEM (HyClone) supplemented with 1% sodium pyruvate, escribed . 1.5 × 1m4-KRAB) ,96, 100 m4-KRAB) ,97. The m4-KRAB) .6 HeLa cells were seeded in T75 flasks 16–18 h prior to transfection. Briefly, 1 ug of the Alu reporter plasmid expressing reverse-complementary neo resistance tag  and 5 uL of lipofectamine (Invitrogen) Cytoplasmic RNA was isolated, polyA-selected and used for PE sequencing as described previously (HeLa cells were cultured as previously described in MEM (HyClone) supplemented with 1% sodium pyruvate, escribed . 1 × 105eviously . RNA-Seqeviously ,88. The L1 loci with intact ORF2 were determined based on database information of ‘Human Full-Length, Intact LINE-1 Elements’ and ‘Human ORF2 Intact LINE-1 Elements’ from L1Base 2 P < 0.0001; HEK293: 42 loci, P < 0.0001; Chi Square analysis)  was significantly higher than in HeLa  and near-significant in HEK293 , although the HeLa results are partially a reflection of the lower threshold of mapped reads for expression (see Methods). We then determined the expression status of the 162 MCF7-expressed loci in HeLa and HEK 293 cells, finding only 16 and 19 of these loci to be expressed in HeLa and HEK293, respectively   Figure . The avey Figure . Becausenalysis) . This maet al. . L1 loci containing intact ORF2p have the potential to generate DNA double strand breaks even in the absence of retrotransposition ,101. We et al. ) and fouP < 0.0001, Chi square analysis) . It is possible that some of these loci express at a low level that is indistinguishable from the surrounding passive transcription. Analyses of ATAC peaks in HeLa and HEK293 show a significant increase in ATAC peaks detected at expressed versus unexpressed L1 loci in both HeLa  and HEK293   Figure . Some of) Figure . Only 49P < 0.0001, Chi square analysis) at promoters of L1 loci expressed in MCF7 cells as compared to unexpressed loci   , and HEK293 cells    . In HEK2nalysis) . A signi) Figure , HeLa (2 t-test) . In addi t-test) , left. W t-test) , right.  t-test) . This ison test) .In addition to the significantly higher levels of activating histone marks associated with expressed versus unexpressed L1 loci in MCF7 cells Figure , B, we oP < 0.0001, Student's t-test)  and HEK293 cells   compared to either unexpressed loci (60.82%) or total loci (60.01%)  Figure . However t-test) . The sig t-test)  as well  t-test) . AdditioDue to the significantly different expression patterns between MCF7, HeLa and HEK293 cells Figure , we hypoThree dimensional (3D) chromatin interactions can strongly influence transcriptional state and regulation . We utilAnalysis of active histone marks shows that seven of the ten expressed L1 loci discussed above are associated with enhancer-like genomic regions that contain high levels of activating histone marks Table . All butTTC28 gene allowed exploration of reasons underlying differential expression of L1 loci that are present near one another in the human genome. This gene is located on chromosome 22 and harbors seven intronic, full-length L1 elements  and analysis of the seven L1 loci in the TTC28 gene for chromatin accessibility, activating histone marks, and percentage of methylated CpGs  determinTTC28 region using CHIA-PET data show direct RNA pol II interactions only with L1-5219 promoter that connects this locus with a putative enhancer  linkages, a marker for open chromatin, overlap specifically with L1-5219.3D interactions in the r Figure . The assn = 18) have a significantly higher number of mapped reads that could map uniquely than loci without an ATAC peak (n = 228)  . We also observed significant differences between loci with and without an ATAC peak when comparing both number of activating histone marks  and percent of methylated CpGs   Figure . Additio) Figure , we also) Figure  and C. OL1-0521 is an example of a poorly mappable L1 locus that is likely expressed in MCF7 cells based on its epigenetic features . This loP < 0.01, P < 0.0001, Student's t-test). When replacing the Cas9-VP64 fusion with a Cas9-KRAB fusion in this system (CRISPR/Cas9i), we see a significant reduction in the L1 5′ UTR-driven reporter-gene expression when co-transfecting a pool of gRNAs as opposed to a negative control gRNA targeting AAV   and CRISPR/Cas9 inhibitor- (CRISPR/Cas9i) based gene regulation system ,114 with t-test) .R) selectable marker. Co-transfection of the Alu reporter plasmid, Cas9-VP64 plasmid, and a pool of gRNAs targeting the L1 5′UTR resulted in 3.2 times as many colonies as were observed in the presence of control gRNA targeting AAV    Figure . In cont) Figure  and in n) Figure ,D.In order to identify which endogenous L1 loci are transactivated by the CRISPR/Cas9a system and the gRNAs targeting L1 sequences using RNA-Seq, we transfected HeLa cells with the CRISPR/Cas9a-expression plasmid along with the pool 2 plasmids expressing gRNAs shown in Figure n = 3638), demonstrating that only some L1 loci that may be somehow marked for expression can be stimulated through the recruitment of transcriptional activators.To determine which endogenous L1 loci were stimulated under these experimental conditions, we manually curated the L1 loci with 5 + mapped reads in both the CRISPR/Cas9a-treated cells and the empty gRNA plasmid control cells according to their individual expression level. All L1 loci with expression levels identified as 5+ reads in either the CRISPR/Cas9a-treated or control samples that pass manual curation are used for this comparison. We reported the expression level for each of these loci in both the activated and control cells  and loci that are unexpressed (0 mapped reads) in both the CRISPR/Cas9a-VP64-treated cells and control cells (n = 3638). We found a significant enrichment for ATAC peaks for the group of L1 loci that were subject to stimulation     . Additio t-test) , but not t-test)  between in vivo . Combining ATAC or activating histone marks with RNA polymerase II association with an enhancer sequence in MCF7 cells provides even more power Table . As onlyOur analysis of epigenetic marks at individual expressed and unexpressed L1 loci establishes a roadmap for manipulation of L1 loci expression either through a CRISPR/Cas9a system or knockout of specific sequences, as well as for studies of normal changes occurring at L1 promoters in different biological settings. We would predict that the ‘transitional’ loci in a tissue would be most prone to activation during development or through the oncogenic transformation. In fact, combined with cell type specific L1 mRNA expression , our finPerhaps the most general finding in our studies is that the L1 element by itself is probably insufficient for significant expression without help from its local genomic environment. Some level of open chromatin, allowing detection of an ATAC signal at the promoter, as well as activating histone marks is clearly necessary, but not sufficient for L1 expression as demonstrated by the presence of ‘transitional’ L1 loci. A dominant feature of expressed L1 loci also seems to be the presence of a three-dimensional interaction between the L1 promoter and a strong enhancer. Unlike a typical gene whose entire genomic environment evolves as a unit or a virus that brings its own enhancer, a new L1 insert is placed in a completely unique sequence and epigenetic environment. The distinct features of individual environments will immediately have specific, but likely different, influences on expression for newly inserted L1 loci. Thus, following integration, each L1 locus will evolve as a completely independent gene. This is supported by the results of our CRISPRa stimulation of L1 expression Figures  and 10. Overall, in this study we identify key local  and long-distance  epigenetic features that are different between expressed and unexpressed L1 loci. We demonstrate their relative power in distinguishing expressed from unexpressed L1 loci. We demonstrate that our discoveries can be used for predicting expression of poorly mapped, but the most disease relevant, L1Hs loci, expression of which cannot be unambiguously determined by RNA-Seq alone. Based on their epigenetic and expression status we identify a new category of L1 loci we term ‘transitional’ because they have several epigenetic features unique to expressed L1 loci even though they are not expressed. Using L1-specific CRISPR/Cas activation and inhibition approaches, we demonstrate as a proof-of-principle that expression of individual endogenous L1 loci can be manipulated, but the three classes of L1 loci  respond differently to this manipulation with transitional L1 loci being the most responsive to the induced activation. Finally, we demonstrate that activation of endogenous L1 mRNA expression is biologically relevant and measurable because we observe a significant increase in Alu retrotransposition in response to L1 activation.https://dataview.ncbi.nlm.nih.gov/object/PRJNA724674?reviewer = hs0mv88e2vgn8br01t2pbm139r.All data will be made available to the public upon publication. The manuscript's metadata is available for viewing via SRA at Publicly-available data can be accessed at the following accession numbers:RNA-Seq:MCF7: ENCFF000HSC and ENCFF000HSK (ENCODE)HeLa: Data can be found at link provided in AVAILABILITY section (SRA)HEK293: SRR1275413 (GEO)ATAC-Seq: Data for MCF7, HeLa and HEK293 can be found at link provided in AVAILABILITY section (SRA)WGBS: Data for MCF7, HeLa and HEK293 can be found at link provided in AVAILABILITY section (SRA)Histone Marks CHIP-Seq (ENCODE):MCF7H3K27AcENCSR752UODH3K9AcENCSR056UBAH3K4Me3ENCSR985MIBH3K4Me2ENCSR875KOJH3K4Me1ENCSR493NBYH4K20Me1ENCSR639RHGHeLaH3K27AcENCSR000AOCH3K9AcENCSR000AOHH3K4Me3ENCSR340WQUH3K4Me2ENCSR000AOEH3K4Me1ENCSR000APWH4K20Me1ENCSR000AOIHEK293H3K27AcENCSR000FCHH3K4Me3ENCSR000DTUH3K4Me1ENCSR000FCGAdditional information regarding data used in this manuscript can be found in the Materials and Methods section.gkac013_Supplemental_FilesClick here for additional data file.


Recently, considering the excellent physical/chemical/mechanical properties , graphene and its derivatives have emerged as an appealing material in developing ERAs. In this review, we have summarized the recent advances in graphene-based ERAs. Typical the working mechanisms of graphene ERAs have been introduced. Design principles and working performance of three typical types of graphene ERAs  have been comprehensively summarized. Besides, emerging applications of graphene ERAs, including artificial muscles, bionic robots, human-soft actuators interaction, and other smart devices, have been reviewed. At last, the current challenges and future perspectives of graphene ERAs are discussed.Electro-responsive actuators (ERAs) hold great promise for cutting-edge applications in e-skins, soft robots, unmanned flight, and   •Actuators enable controllable shape morphing under external stimulations•Design principles and working performance of graphene ERAs have been summarized•Emerging applications of graphene ERAs have been reviewed The typical working mechanisms of ERAs that are made of graphene are introduced, in which the role of graphene in such ERAs has been highlighted. Also, the design principles  and unique properties of graphene-based ERAs are comprehensively reviewed. After that, the emerging applications of graphene-based ERAs, including artificial muscles, bionic robots, human-soft actuators interaction, and other smart devices, are comprehensively summarized. Last, the current challenges and future perspectives of graphene-based ERAs are discussed.ERAs can be designed and fabricated based on different working mechanisms. In this section, typical actuation strategies for graphene-based ERAs are introduced , includi,Electrostatic actuation deforms by attraction or repulsion between charges A. For elTypically, electrothermal actuation is based on bi-/multilayer structures B, in whiFurthermore, electrothermal actuators can achieve complex three-dimensional (3D) deformations by rational structure design. Nevertheless, graphene-based electrothermal actuators require high applied voltage (dozens of voltages) to achieve large bending curvature and suffer from low response/recovery speed because the thermal expansion/contraction rate of materials  is relatively low. Besides, the mechanical stability of electrothermal actuators needs to be improved because frequent bending/unbending may induce interlayer shedding.Ionic actuators contain two electrodes and an electrolyte layer C. Under 3/PDMS film is 1.12 mm at 63.4 MV/m.Electrostatic actuators show displacement by the attraction or repulsion between charged objects. For example, Kim et al. developed graphene-optically clear adhesive-graphene (G-OCA-G) sandwiched dielectric elastomer actuators by roll-to-roll methods.,,−4 N m−1). Besides, the RGO springs show a linear relationship between the strain (within 300%) and applied force (∼0.04 mN). Therefore, due to the repulsion between the charged loops, RGO springs process approximate linear length changes when the applied voltage is raised from 0 to 3.5 kV. Remarkably, the RGO springs show excellent elongate rates (ca. 210% per s) under an electrostatic field (3.5 kV), showing potentials in developing electrostatic switches.In addition to the dielectric elastomer actuators, Fujiwara et al. demonstrated electrostatic actuation by applying the voltage between a probe electrode and the multi-graphene.To develop contactless actuators, He et al. fabricated contactless GO strip-based electrostatic actuators by attaching a positively charged GO strip on a negatively charged polystyrene (PS) Petri dish D.106 The−4 K−1) is larger than RGO (30 × 10−6 K−1).,−1) by applying a low current density (0.74 A/mm2). It is worth noting that the RGO/PDA actuators show ultrafast switch behaviors even up to 200 Hz under an alternating current, which may contribute to fabricating artificial muscles and robots.As we know, electrothermal actuators are typically bi-/multilayer structures. The whole structure bends because of the electrothermal stress mismatches at the interface of different layers. For example, Liang et al. successfully fabricated RGO/polydiacetylene (PDA) bilayered electrothermal actuators by the thermal-/electric-induced expansion of PDA.−6 K−1), excellent electrostrictive performance, and piezoelectric effect performance.To improve the actuation performance, Xiao et al. chose large CTE materials (polyvinylidene fluoride [PVDF]) as the electric-induced expansion layer and fabricated RGO/PVDF electrothermal actuators A.110 The,−1 (V = 30 V). Instead of producing joule heating, the LIG has porous structures after the laser treatment, contributing to the PDMS penetration into porous structures and enhancing the interfacial adhesion between the LIG and PDMS layers. As a result, the PI/LIG/PDMS electrothermal actuators show no significant bending/unbending performance degradation over 1000 times. More importantly, inspired by origami creases and kirigami cuts, this method has realized 2D to 3D shape deformations through global folding and local bending by laser thinning (thickness control) and laser cutting (cutting patterns control) technologies. Impressively, more than 20 predetermined 3D architectures have been designed and fabricated  and LIG.bricated D. This w−1 under 5 V @ 0.01 Hz. The normalized tip displacement maintains above 90% after 6 h, whereas the tip displacements of conventional ionic polymer-metal composite actuators drop rapidly below 50% after 6 h. This work fully indicates the advantages of the graphene electrode layer compared with the traditional noble metal electrode layer. In addition, Tabassian et al. proposed a self-sensing ionic actuator, which senses bending deformation under actuation.In this section, we summarize the fabrication methods and unique characters of graphene-based ionic actuators. Typically, Kim et al. fabricated laser-scribed-RGO (LS-RGO) paper electrodes asymmetrically for highly durable ionic polymer-graphene composite actuators A.127 For3O4,, nickel oxide nanowalls@RGO–multiwalled carbon nanotubes,2,To improve graphene-based ionic actuator performances, various strategies, including heteroatom doping, material compositing, and hierarchical structuring, have been developed to improve conductivity and provide active sites for electrochemical reactions. Kotal et al. fabricated sulfur/nitrogen co-doped RGO (SNG) by a microwave-associated method and developed SNG/polyethylenedioxythiophene: polystyrenesulfonate (SNG/PEDOT:PSS) electrodes to enhance electrochemical activities B.129 Com3N4/nitrogen-doped grapheneIt is worth noting that Kotal et al. recently reported nitrogen-enriched 3D g-C4 S/m). Interestingly, the light-emitting diode chips integrated with RGO circuits keep bright illumination upon bending and twisting  and N-doped crumpled RGO (NG).Significantly, the bending motions show abilities in kicking, hooking, and grasping.2-nSNRGO) with high conductivity and high capacitance. Accordingly, the pMoS2-nSNRGO–based ionic actuators show larger displacement (670% improvement) than RGO-based ionic actuators at 0.5 V and 1 Hz. The low actuation voltage may play an essential role in connecting actuators into control systems for practical applications. The soft-touch fingers can turn on/off the smartphone's flashlight. Besides, as shown in Instead of shape deformation, Manzoor et al. developed soft-touch fingers ionic actuators for touching smartphones and tablets.The design of ERAs based on graphene can be used to design insect-like motions, such as flapping motions, moving movements, and even preying biomimetic frog tongues.2 plasma reactive ion etching. Then the graphene/SU-8-based micro-electrothermal actuator bends to the graphene side by applying the electric actuation. Additionally, the graphene/SU-8-based micro-electrothermal actuators show a displacement of 1 μm in 0.02 s by using a 1 V and recovery voltage to the initial position in ∼0.1 s. The efficient bonding (π-π interaction) between graphene and SU-8 helps avoid delamination up to 0.4% strain.Zhu et al. developed graphene/SU-8-based micro-electrothermal actuators for transparent dragonfly wings.2) and a small part (∼8 mm2). The small part produces a larger amplitude than the large part (±20 mA @ 50 Hz). Therefore, the bidirectional moving robot moves from right to left due to the different amplitude between the large and small parts. On the contrary, the large part produces a larger amplitude than the small part (±16 mA @ 50 Hz). As a result, the bidirectional moving robot moves from left to right.Xiao et al. demonstrated a fish-like robot consisting of a polystyrene body (30 mm × 8 mm) and an RGO/PVDF actuator (14 mm × 3 mm) based tail B.110 TheUnlike the works mentioned above in this section, Ling et al. recently fabricated a biomimetic frog tongue that is capable of capturing flies under 20 V actuation C.39 The He et al. demonstrated GO film-based radar and dancers, showing great potentials in developing human motion monitors.Instead of the electrostatic force directly inducing shape deformation, Ling et al. achieved human gestures for controlling actuators' 3D shapes via real-time monitoring of human electromyogram (EMG) signals B.39 LIG-Graphene can be used as the electrode of dielectric elastomer actuators to prepare variable focus lens. Typically, Hwang et al. developed a variable focus lens using a few-layer-graphene (FLG) electrode.Besides, graphene can be used as the electrode of piezoelectric actuators to fabricate flexible loudspeakers. Bae et al. demonstrated a transparent piezoelectric actuator with G-P(VDF-TrFE)-G sandwiched structures.−1) and the GO layer (0.85 ppm K−1).ERA integration with other external stimuli, such as light and moisture, can achieve cutting-edge applications. Ma et al. developed a tape/RGO/GO actuator-based smart curtain by the binary cooperative complementarity A.126 As In recent years, graphene and relative innovations have developed broad and important applications. Especially, graphene has become an attractive candidate for fabricating stimuli-responsive actuators. In this review, we summarize recent innovations of ERAs based on graphene, in which typical actuation mechanisms, including electrostatic actuation, electrothermal actuation, and ionic actuation, have been reviewed. In developing these ERAs, graphene and its derivatives prepared in different ways play an essential role. As compared with other carbon materials, the outstanding physical/chemical properties, the large specific surface, excellent stability, mechanical strength, and high electrical/thermal conductivity make graphene a promising candidate electrode for ERAs. In most cases, the use of graphene can promote the actuating performance significantly and facilitate the fabrication of ERAs. To make a comprehensive comparison of the performance of different types of graphene-based ERAs, we have summarized the reported critical properties of graphene ERAs in For ERAs based on electrostatic actuation, the working mechanism is the interaction of electric charge-induced attractions or repulsions between graphene electrodes. Here, graphene can either serve as the electrode material or work as a dopant to increase the dielectric constant of the dielectric elastomer, which improves the performance of dielectric elastomer actuators. Generally, dielectric elastomer actuators show high-frequency response, but suffer from high-applying voltages and relatively small displacement, which more or less limits their applications. Nevertheless, due to the high response rate, electrostatic actuators have been successfully employed for artificial muscles  and human-machine interaction . Nevertheless, for much broader applications, their performance still needs further improvements to achieve much lower driving voltages and larger displacements. Recently, spring-shaped micro-electrostatic actuators that can work under lower voltage (110V) have been reported, which show much larger displacements . These works provide a hint that electrostatic actuators can be optimized by designing novel device structures, reducing the device dimensions, and using high-quality graphene as electrodes.In the case of graphene-based electrothermal actuators, the device structure is a common bilayer or multilayer, in which graphene electrodes convert electrical energy into heat, inducing the thermal expansion of coupled material layers. In addition to the electrodes, graphene plays very important roles, including electrothermal generation, heat conduction, and negligible thermal expansion. Generally, electrothermal actuators feature a very simple device structure and preparation process. Many technologies, including drop-coating, ink printing, vacuum filtration, photopolymerization, and casting, can be employed to prepare graphene electrothermal actuators. Nevertheless, this actuation scheme usually suffers from low energy conversion efficiency, and the actuation voltage is still more than 10 volts. To reduce the actuation voltage and increase displacements, improvements can be made by using graphene electrodes with more obvious electrothermal effects and active materials with larger CTEs. Besides benefiting from the patterned and periodically structured graphene electrodes , electrothermal actuators also enable complex shape morphing beyond simple bending. To get better control over the electrothermal deformation, graphene electrodes can be combined with shape-memory materials. In that case, the temperature-determined reversible shape transition between different states may lead to broad applications.Ionic actuators generally consist of metal electrodes and electrolytes. However, in most cases, metal electrodes suffer from poor stability considering the leakage of electrolytes and mobile ions. Recently, graphene has emerged as an appealing alternative due to its chemical stability, superhydrophobicity, high electrical conductivity, specific surface area, and flexibility. Generally, ionic actuators can be prepared using different graphene electrodes. RGO-based electrodes can be readily prepared, while they suffer from relatively low conductivity. To make a further improvement, strategies including micro/nano-structuring, heteroatom doping, or nanoparticle/wire hybriding and the construction of P-N junction have been developed to enhance the electrochemical properties. Besides, CVD-grown graphene has been also used as the electrodes to increase the electrical conductivity. Consequently, ionic actuators with fast response (<1 s), excellent stability, and low voltage actuation (<1 V) have been developed, revealing the great potential for artificial fingers, fish fin, and insect wings.The use of graphene for developing ERAs shows distinct advantages and several shortcomings. In most cases, graphene works as an electrode. As compared with other carbon electrodes, for instance CNTs, the merits of graphene lie in the unique 2D nanosheet structure. It can form very thin electrodes with high transparency, flexibility, mechanical strength, and tunable chemical/physical properties. On the contrary, the shortcomings of graphene are also obvious, for example, the use of graphene may increase the cost of devices because all kinds of graphene electrodes, including RGO, LIG, and CVD-graphene, cannot be produced by industry at present. Besides, graphene electrodes prepared different ways may have distinct properties. For instance, RGO electrodes usually have relatively lower conductivity than CVD-graphene, but more electrochemically active sites. The patterning/structuring of RGO and LIG is much easier than CVD-graphene, since the former type of graphene is generally multilayer graphene, whereas the later one is single- or few-layer graphene. In this regard, it is not accurate to simply discuss the shortcomings of the graphene without pointing out which types of graphene. Different graphene electrodes may be suitable for different ERAs. Currently, an obvious limitation for practical use of graphene might be the uniformity of graphene electrodes prepared through different methods and even through the same method but from different batches. For example, in the case of RGO electrodes, the size of raw graphite, the oxidation condition, and the reduction methods are all crucial factors for the quality of RGO samples. Consequently, it is quite urgent to establish relevant standards for both graphene preparation and the quality of the resultant products. To make a comprehensive comparison of the performance of different types of electrode materials for ERAs, we have summarized typical examples of ERAs based on graphene and other conductive materials in At present, despite the rapid advancements, graphene-based ERAs are still at an early stage. Current challenges for developing high-performance ERAs mainly lie in the following three aspects: (1) high-quality graphene electrodes with high uniformity that can be practically applied to ERAs are still rare; (2) the optimization of device structures and performance; (3) the integration of ERAs with control circuits. Besides, graphene-based ERAs may feature ultrathin device structure, light weight, flexibility, and mechanical robustness, as compared with ERAs based on other materials. Therefore, another challenging task for ERAs is their broad applications in different fields. Actually, the issues mentioned above are not independent but inter-constraint with each other. Consequently, the development of graphene-based ERAs depends on the overall progress of material sciences, nanotechnologies, and electronics. It is possible that with the improvement of graphene preparation/processing technologies and the innovation of advanced flexible electronics, graphene-based ERAs may develop rapidly and find broad applications in the near future.


We present a model of impurity-induced magnetization of graphene assuming that the main source of graphene magnetization is related to impurity states with a localized spin. The analysis of solutions of the Schrödinger equation for electrons near the Dirac point has been performed using the model of massless fermions. For a single impurity, the solution of Schrödinger’s equation is a linear combination of Bessel functions. We found resonance energy levels of the non-magnetic impurity. The magnetic moment of impurity with a localized spin was accounted for the calculation of graphene magnetization using the Green’s function formalism. The spatial distribution of induced magnetization for a single impurity is obtained. The energy of resonance states was also calculated as a function of interaction. This energy is depending on the impurity potential and the coupling constant of interaction. One of the most interesting aspect of current reserch in graphene-based materials is to understand the magnetic properties in doped graphene. Investigation of electron transport properties and structure of electron orbitals is one of the most important aspects of testing graphene for electronic purposes. Moreover, from the point of view of spintronics applications, research is conducted to determine spin transport and spin polarization capabilities of graphene-based devices. Recent studies of the ferromagnetic properties of doped graphene at room temperatures indicate a great potential electronic application of this material. In parallel with experimental research, it is necessary to gain an in-depth understanding of the theoretical aspects underlying the unique properties of graphene. In our paper, we focused on calculations of magnetization and resonant energy levels of the impurity located at the graphene lattice.The main objective of this work was to determine the wave function and corresponding eigenenergy of a localized state for the graphene lattice with impurity ,2. Such We also found that impurities induce the magnetization of graphene that can be calculated by introducing the disorder operator into the Dirac Hamiltonian . For theMagnetic impurities are responsible for creating a system of isolated magnetic moments in graphene. Magnetic interactions between these moments are depending on their specific location in the graphene sublattices and the density of free electrons (holes). Besides, the particularity of graphene electron structure makes it possible to appear an indirect RKKY interaction in the absence of free carriers through the polarization mechanism of electron-hole system . As a reAnother mechanism of magnetic ordering leading to possible transition from dominating ferromagnetic to antiferromagnetic ordering has been proposed for the case of graphene nanoribbons . It was It was also found that the charge transfer between the electron states localized at the zigzag edge and the magnetic impurity state is important for magnetic properties of graphene. It was shown that this mechanism can lead to the compensation of magnetic moment at the nanoribbon edge .For the case of graphene bilayers with impurities adsorbed on one layer and gated by electric field perpendicular to the layers, one can observe the bound states with energies in the gap . These sThe magnetism of graphene resulting from interaction between transition-metal and carbon atoms can be also analyzed by taking into account the spin polarization of metallic impurities. The calculations of magnetic moments indicate a significant doping-induced magnetization effect .Our article is divided into several sections. In m is the rest mass of electron, c the light velocity, and Most importantly, from the point of view of electronic properties of graphene, is a neighborhood of the Dirac point. Here the energy bands form the Dirac cone, shown in K is linear. Similarly, for a Dirac point K point, we present the wave function of this Hamiltonian in the momentum representationFor the wave equation we use the Weyl–Dirac Hamiltonian (WDH), which in the wave vector representation f matrixH^0,k=0vkK i K and The signs “+” and “−”correspond to conduction and valence bands, respectively. The phase factor  ,18,19.KLet us consider the graphene lattice with a single impurity  hasEquation  describeFrom the Schrödinger equation we obtain the Bessel differential equation (9)ϱ2d2dThe solutions of this Equation  are Bessctively, ,23. The Equation . By applThe general solution for the wave function solution . Finallysolution (12)Ψms(r)A. The expression ϑ1 the electron charge given by We consider a graphene monolayer sample. At the point Equation  and presBy analyzing pression .As we mentioned, the spin density depends on the distribution function function  is the aolutions  contain As shown by Abrikosov  on an exIn our model we assume that the localized charge on impurity is the reason of spin polarization in the graphene lattice. This polarization is related to the magnetic moment, which is proportional to Taking into account the energy relation  leads toinclusion spin polarization for different values of the coupling constant As can be seen in The results, which are marked with a circle, correspond to inclusion of the magnetic interaction energy. Let us denote the energy of impurity level after renormalization as  Formula  assumes We should study the convergence of the sequence To date, the magnetic correlations were not properly considered in the doped magnetism of graphene or carbon materials in general. Our results show that they can be of fundamental importance. A separate issue is the effect of RKKY oscillations on the magnetic state. The variation of chemical potential Here we discuss the impurity-induced electronic and magnetic properties of graphene, especially the role of impurity in formation of the localized states with resonant energy levels ,34. The As a result of calculations we have determined the energy levels of dopant localized states in graphene. We have described the local magnetization induced by the presence of the dopant. We have consider the effect of the potential perturbation induced by the presence of the impurity, and we study the relation between local magnetization and distance from the impurity center. To calculate the results of spin projections on the magnetization axis, we examined the method of Green’s functions. Finally we include the interaction energy of a localized magnetic moments as a function of normalized impurity potential.The obtained results show a significant and measurable effect of doping on the electron structure and magnetic properties of graphene. These results are in agreement with previous work indicating that doping of graphene can be used to obtain a material with desirable transport properties of both electric charge and spin currents. At the same time, the work done indicates that many properties of graphene need further investigation both on the ground of theory and experiment. Improvement of computational technique using perturbation theory as well as reaching for tools that go beyond perturbation methods seems to be important in further research.


Rolling enables the directional alignment of the reinforcements in graphene/Cu composites while achieving uniform graphene dispersion and matrix grain refinement. This is expected to achieve a breakthrough in composite performance. In this paper, the process parameters of rolling are investigated, and the defects, thickness variations of graphene and property changes of the composite under different parameters are analyzed. High-temperature rolling is beneficial to avoid the damage of graphene during rolling, and the prepared composites have higher electrical conductivity. The properties of graphene were investigated. Low-temperature rolling is more favorable to the thinning and dispersion of graphene; meanwhile, the relative density of the composites is higher in the low-temperature rolling process. With the increase of rolling deformation, the graphene defects slightly increased and the number of layers decreased. In this paper, the defect states of graphene and the electrical conductivity with different rolling parameters is comprehensively investigated to provide a reference for the rolling process of graphene/copper composites with different demands. Cu metals, alloys, and composites are widely used in industrial production. Cu has excellent electrical and thermal conductivity, as well as good processability and corrosion resistance, second only to Ag ,2. They However, the current development of graphene/Cu composite faces the following problems. Since graphene is a nano reinforcement, it is very easy to agglomerate after being prepared into a composite, which causes the two-dimensional strengthening characteristics of the graphene to fail to fully play, which reduces the performance ,17. In a4C3 was observed at the interface.The uniform dispersion of graphene in the metal matrix can be achieved through the deformation of the composites. Shao et al. ,21 foundWang et al.  reportedThe parameters of the deformation have an important influence on the dispersion and deformation of graphene in the matrix, but the rules are still unclear. However, the research on the specific effects of deformation temperature and deformation on the structure and properties of the composite is not comprehensive enough.In this work, the microstructural evolution behavior of graphene under different rolling parameters was studied. Due to the stable chemical properties of Cu and no interfacial reaction with graphene, it was convenient to observe the deformation behavior of graphene. Therefore, Cu was selected as the matrix for preparing composites. In order to clarify the deformation behavior of graphene in the matrix, this paper comprehensively studied the effects of deformation temperature and rolling deformation on graphene/Cu composites. The organization evolution of graphene was studied through Raman spectroscopy, and the mechanical and electrical properties were tested, which provide a reference for subsequent deformation of composite materials.−1, the G peak at 1570 cm−1, and the 2D peak at 2700 cm−1. The D peak reflects the asymmetric lattice vibrations, and the G peak reflects the symmetrical lattice vibrations [D/IG) is often used to reflect the change of graphene defects. 2D peaks appearing at approximately 2700 cm−1 is related to the number of graphene layers. And the peak position, peak shape, and intensity of 2D peaks can be used to judge the number of graphene layers [The graphene used in this experiment was supplied by the Sixth Element Changzhou Materials Technology Co. Ltd. China. The pure Cu powder used in this study was purchased from Beijing Xingrongyuan Co., Ltd., Beijing, China, with a purity of 99.9% and an initial particle size of about 3 μm. The characterization of graphene and Cu powder is shown in brations ,30. The e layers ,32,33. Te layers ,35.In this study, a planetary ball mill  was used to disperse the graphene, and the ball-milling speed of 120 r/min for 2 h was used. The content of graphene is 0.6 wt.%. The mixed graphene-Cu mixed powder is sintered through SPS. The powder mixture of GNPs and Cu was put into a 40 mm diameter mold and pressed into preforms at a pressure of 40 MPa. The pressure was maintained for 5 min. The mold with the preforms was then placed into the SPS equipment and heated to 1020 °C at 5 °C/min and kept at high temperature for 10 min. The current-to-time ratio (ton:toff) during sintering was 2:1. After the sintering was completed, the sample was cooled to room temperature in the mold with the furnace. The prepared 0.6 wt.% GNPs/Cu composite was subjected to subsequent rolling research.In this work, a double-roll mill  is used to optimize the deformation of the prepared composite. Under the action of the stresses generated during the rolling process, the Cu matrix and graphene undergo shear deformation. The total thickness reduction (%) is counted as the amount of down-compression deformation. The 0.6 wt.% graphene/Cu composite material was cut into 55 mm × 10 mm × 4 mm rectangular parallelepiped and rolled from the original thickness of 4 mm. The prepared composite is rolled at 20 °C, 300 °C, 500 °C, 700 °C. The deformation amount of each rolling is 10%, and the samples with large deformation amounts are prepared by the method of multiple rolling. The total reduction of multiple rolling is 20–80%. The hardness and electrical conductivity of the composites were subsequently investigated at different rolling temperatures and deformation amounts.mρ and Hρ2O are the densities of the composite and the sample, respectively, and m1 and m2 are the masses of the composite in air and water, respectively. The relative density is the ratio of the experimental density to the theoretical density of the sample.Morphologies of the GNPs/Cu powders and the composites were observed by FEI Quanta 200FEG . Raman analysis was performed on a JY-HR800 laser Raman spectrometer  using a 532 nm solid-state laser as an excitation source. The image analysis microhardness of HV-1000IS  was used to test the Vickers hardness of the graphene/Cu composites. In the hardness test, the experimental parameter load is 200 gf, the pressure time is 15 s. An FD 102 digital eddy current conductivity meter  was used for the conductivity test. Each sample is randomly measured 5 times at a certain distance, and the average value is obtained. The density of the material was measured by Archimedes’ drainage method. The mass of the sample in air and the mass in water are tested separately and the density of the material is calculated according to the formula:D/IG of graphene in the composite before rolling is 0.20, and the I2D/IG is 0.43. The state of the graphene in the sintered composite is close to that of the raw graphene because the graphene is less damaged during the preparation processing. The defect content of graphene only increased slightly, and the number of layers did not change significantly.The GNPs/Cu composite material was rolled and deformed at rolling temperatures of 20 °C, 300 °C, 500 °C, and 700 °C, and the total deformation was 80%. Raman characterization of the composite material, the results are shown in After rolling at different temperatures, the graphene changes significantly. Comparing the positions of the characteristic peaks of the Raman spectrum curve at different rolling temperatures, it can be seen that the positions of the D peak and the G peak are basically the same. The peak shape of the 2D peak changes slightly due to the change in the number of graphene layers. The ratio of the intensity of change of the graphene D peak, the G peak, and the 2D peak is quantified, as shown in D/IG of graphene increased significantly compared to the unrolled graphene/Cu composites, indicating a significant increase in the defect content in graphene. Graphene suffers huge damage during the rolling process. I2D/IG also increased slightly, indicating that the number of graphene layers decreased during the rolling process.It can be seen that when the composites were rolled, the ID/IG and I2D/IG drops slightly. It shows that after the rolling temperature is increased, the rolling damage to the graphene is less, and at the same time, the peeling effect of the graphene is reduced. This is because when the rolling temperature is lower, the composite is subjected to greater stress during cold rolling. Graphene shears, bends, and twists as the substrate deforms, creating more edge and hole defects. At the same time, the large shear stress also causes the multi-layer graphene layer to slip, which reduces the number of graphene layers. To further characterize the changes in the number of graphene layers at different rolling temperatures, the deviation of the graphene G peak and 2D peak is observed, as shown in the As the rolling temperature rises, I−1. Based on the results reported in other papers [Based on the research results of Malard et al. , as the r papers ,33, it cAt 700 °C, under the condition of 10% deformation in a single press, the composite is subjected to multiple rolling treatments. The total rolling deformation is 4.0 mm → 10% (3.6 mm) → 20% (3.2 mm) → 30% (2.8 mm) → 60% (2.4 mm) → 50% (2.0 mm) → 60 (1.6 mm) → 70% (1.2 mm) → 80% (0.8 mm). The Raman characterization of rolled composites with different deformations is performed, and the results are shown in D/IG ratio of different total deformations has shown an upward trend from 20% to 80%, indicating that the defects of graphene are gradually increasing during the rolling process. At the beginning of rolling, the value of ID/IG has a large standard deviation value, indicating that the structure is not uniform in the initial stage of deformation. When the total deformation is 40%, the standard deviation values of the ID/IG ratio begin to decrease, indicating that the change of graphene begins to stabilize. As the rolling deformation continues, when the total deformation reaches 70%, the ID/IG ratio once again greatly increases. The graphene defects increase significantly, and the variance of the ID/IG ratio continues to increase. It showed that in the later stage of rolling deformation, under the action of large deformation, the Cu matrix began to crack, and stress concentration was formed at the crack during the deformation, which caused more serious damage to the graphene near the crack.The intensity ratio of the D peak and the G peak is quantitatively calculated to determine the state of graphene defects, as shown in The shift of graphene G and 2D peaks in rolled composites with different deformations was observed, as shown in To further study the change law of the composite microstructure and explain the abnormal rise of graphene defects after the deformation exceeds 70% during cold rolling, the relative density and microstructure of the composite are characterized.The relative density of the composite rolled at different temperatures and different deformation amounts are shown in SEM observation is performed on the 0.6 wt.% graphene/Cu composite rolled at 20 °C, and the reason for the decrease in density is analyzed, as shown in The hardness test of the composite after rolling treatment at different temperatures and deformations is shown in Combining the density and the Raman characterization, the reasons for the performance changes can be analyzed. When the amount of rolling deformation is low, as the amount of deformation increases, the agglomerated multilayer graphene is thinned, and the matrix defects are reduced, increasing the hardness of the composite. When the deformation exceeds 70%, the Cu matrix will crack and the graphene will be severely broken, which will degrade the properties of composites. The performance after rolling shows an overall downward trend as the temperature increases. Combined with the Raman characterization, it can be seen that when the rolling temperature is lower, the matrix has greater stress, so the graphene has a more obvious thinning effect. At the same time, the graphene is more uniformly dispersed, and the strengthening ability is more easily exerted. Therefore, the material has greater hardness when rolled at low-temperature. The change in the properties of the composites was also related to the change in Cu grain size. It was reported that the Cu matrix grains were found to be coarse at higher rolling temperatures and the material properties decreased substantially ,37,38. IAfterward, the electrical conductivity of the composites rolled at different temperatures and deformations is tested, and the results are shown in As the rolling temperature increases, the conductivity of the composite increases. Based on previous studies, it can be seen that the higher the rolling temperature, the less damage the rolling will cause to graphene. Low-damage graphene has more contribution to electrical conductivity, so the electrical conductivity of composites prepared by high-temperature rolling is higher. The conductivity is also related to the grain size of the Cu matrix, the larger the grain size and the less grain boundary content, the higher the conductivity . The graIn addition, rolling can produce an oriented arrangement of graphene in the composite. Guo et al.  investigIn this work, the microstructure and properties under different rolling temperatures and rolling deformation were systematically investigated. When the rolling temperature decreases and the deformation increases, the thinning effect of graphene during rolling is enhanced, and more damage to graphene is also produced. At rolling temperatures below 300 °C, rolling facilitates the uniform dispersion of few-layer graphene in the Cu matrix. When the temperature is higher than 300 °C, the damaging effect of rolling on graphene can be reduced.The hardness and electrical conductivity of the composites increased with the increase of rolling deformation. When the deformation of low-temperature rolling exceeds 70%, its properties are weakened. The hardness of the composites decreases with increasing rolling temperature, while the electrical conductivity increases with increasing rolling temperature. In this paper, the structural and property changes of the composites under different rolling processes are comprehensively studied to provide a reference for the rolling process of graphene/copper composites with different demands.