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To isolate ß-galactosidase producing bacterial resources, a novel Gram-stain-negative, strictly aerobic bacterial strain designated as A6T was obtained from a farmland soil sample. Cells of the strain were rod-shaped (0.4-0.7 µm × 1.8-2.2 µm) without flagella and motility. Strain A6T grew optimally at 30 °C, pH 7.0 with 0% (w/v) NaCl. Based on phylogenetic analysis, strain A6T clustered within the genus Lysobacter clade and branched with Lysobacter dokdonensis KCTC 12822T (99.5%, 16S rRNA gene sequence similarity) and Lysobacter caseinilyticus KACC 19816T (98.5%). The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain A6T and Lysobacter dokdonensis KCTC 12822T were 82.7% and 26.2%, and the values for strain A6T and KACC 19816T were 81.4% and 23.8%, respectively. Iso-C16:0, iso-C15:0, summed feature 9 (C17:1 iso ω9c and/or C16:0 10-methyl) and summed feature 3 (C16:1ω7c and/or C16:1 ω6c) were the major fatty acids, diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine were the major polar lipids, and ubiquinone 8 (Q-8) was the major ubiquinone. The genomic DNA G+C content was 67.2 mol%. Furthermore, under the condition of 30 °C, pH 7.0, 4% inoculation with 10.0 g L-1 lactose, the ß-galactosidase activity produced by strain A6T was highest, reaching 95.3 U mL-1, indicating that this strain could be applied as a potential strain for ß-galactosidase production. Strain A6T represents a novel species of the genus Lysobacter, and Lysobacter lactosilyticus sp. nov. is proposed on the basis of phenotypic, genotypic, and chemotaxonomic analysis. The type strain is A6T (=KCTC 82184T=CGMCC 1.18582T).
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Lysobacter , Fosfolipídeos , Fosfolipídeos/química , Lysobacter/genética , Fertilizantes/análise , Filogenia , RNA Ribossômico 16S/genética , Solo , Aminoácidos/metabolismo , Fazendas , DNA Bacteriano/genética , Microbiologia do Solo , Ácidos Graxos/química , beta-Galactosidase/genética , Análise de Sequência de DNA , Técnicas de Tipagem BacterianaRESUMO
Accurate discrimination of amyloid-ß (Aß) peptides containing familial point mutations would advance the knowledge of their roles in early-onset Alzheimer's disease. Herein, we simultaneously identified the mutant A21G, E22G, E22Q, and the wild-type (WT) Aß18-26 peptides with aerolysin nanopore using a 3D blockage mapping strategy. The standard deviation of current blockade fluctuations (σb ) was proposed as a new supplement to current blockage (Ib /I0 ) and duration time (tD ) to profile the blockage characteristics of single molecules. Although the WT and A21G Aß18-26 are indistinguishable in a traditional Ib /I0 -tD 2D description, â¼87 % of the blockade events can be accurately classified with half reduction of false identification using a combination of Ib /I0 , tD, and σb . This work offers an easy and reliable strategy to promote nanopore sensitivity of peptide mutants, leading to a more precise analysis of pathogenic mutations for developing effective diagnosis and treatment.
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Doença de Alzheimer , Nanoporos , Humanos , Peptídeos beta-Amiloides/genética , Peptídeos beta-Amiloides/química , Mutação Puntual , Doença de Alzheimer/genética , Mutação , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/químicaRESUMO
Herein, a type of biomass-based electric heating membrane (EHM) with excellent stability was fabricated; this was achieved by incorporating carbon nanotubes (CNTs) into the nanofibrillated cellulose (NFC) as a natural dispersant and a biological substrate, as well as via the control of ultrasonic dispersion, grammage, and encapsulation using poly(dimethylsiloxane) (PDMS) with hot pressing. NFC entangles with CNTs in the form of an intertwined network and non-covalent interactions to fabricate a flexible EHM with steady electric heating performance; this formation is attributed to not only their similar morphology and surface-active groups but also the use of NFC that avoids additional disturbances in the overlapped interface among CNTs as far as possible. The obtained steady resistance varies as low as 5.1% under energized operation. In the encapsulated EHM (EM), PDMS was anchored on its surface by using hot pressing and an intertwined structure to enhance flexibility and robustness. The encapsulated membrane can be used in low-voltage applications, which require flexibility, waterproofing, and insulation.
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Nanobubble nucleation study is important for understanding the dynamic behavior of nanobubble growth, which is instructive for the nanobubble applications. Benefiting from nanopore fabrication, herein, we fabricated a sub-9 nm SiNX nanopore with the comparable size to nanobubbles at early-stage. The confined nanopore interface serves as a generator for producing nanobubbles by the chemical reaction between NaBH4 and H2 O and as an ultra-sensitive sensor for monitoring the H2 nanobubble nucleation process. By carrying out the NaBH4 concentration-dependent experiments, we found the life-time of nanobubbles decreased 250 times and the frequency of nanobubble generation increased 38 times with the NaBH4 concentration increasing from 6 to 100 mM. The long-time equilibrium between gas molecules inward flux and outward flux could prolong the life-time of nanobubbles to hundreds of milliseconds at low NaBH4 concentration. The raw current trace depicted that the transient accumulation and dissolution of cavity occurred during all the life-time of nanobubbles. Therefore, the sub-9 nm SiNX nanopore shows a strong ability for real-time monitoring the nanobubble nucleation at early-stage with high temporal and spatial resolution. This work provides a guide to study the dynamic and stochastic characteristics of nanobubbles.
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Gases/química , Nanoporos , Nanotecnologia/métodos , Boroidretos/química , Hidrogênio/química , Tamanho da Partícula , Água/químicaRESUMO
In this study, we designed SiNX solid-state nanopores to detect the temperature effect on the hydrogen nanobubble formation. Here, we integrated a temperature controller with the highly sensitive nanopore. As the temperature decreases from 25 °C to 5 °C, the occurrence of the nanobubble nucleation inside a 12.3 nm SiNX nanopore confined space decreased from 102 s-1 to 23 s-1, and the life-time of nanobubbles increased from 1.16 ms to 4.78 ms. The results further gave the activation energy for nanobubble nucleation which was 8.1 × 10-20 J with a 12.3 nm SiNX nanopore. Our method provides an efficient analytical tool for revealing the temperature-dependent nanobubble nucleation, which further benefits the fundamental understanding of nanobubble nucleation.
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Nanopore is a single-molecule analysis method which also employed electrophoresis has achieved promising single-molecule detections. In this study, we designed two kinds of confined spaces by fabricating solid-state nanopores with desirable diameters to study the structured single-strand DNA of C-rich quadruplex. For the nanopore whose diameter is larger than the quadruplex size, the DNA molecule could directly translocate through the nanopore with extremely high speed. For the nanopore whose diameter is smaller than the quadruplex size, DNA molecule which is captured by nanopore could return to the solution without translocation or unzip the quadruplex structure into single-strand and then pass the nanopore. This study certifies that choosing a suitable sensing interface is the vital importance of observing detailed single-molecule information. The solid-state nanopores hold the great potential to study the structural dynamics of quadruplex DNA molecule.
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DNA de Cadeia Simples/análise , Eletroforese/métodos , Nanoporos , Nanotecnologia/métodos , Imagem Individual de Molécula/métodos , Desenho de Equipamento , Tamanho da PartículaRESUMO
Nanopore analysis is a powerful technique for single molecule analysis by virtue of its electrochemically confined effects. As a single molecule translocates through the nanopore, the featured ionic current pattern on the time scale contains single molecule characteristics including volume, charge, and conformational properties. Although the characteristics of a single molecule in a nanopore have been written to the featured ionic current, extracting the dynamic information from a complex current trace is still a big challenge. Here, we present an applicable nanopore analysis method employing the Hilbert-Huang Transform (HHT) to study the vibrational features and interactions of a single molecule during the dynamic translocation process through the confined space of a nanopore. The HHT method is specially developed for analyzing nonlinear and non-stationary data that is highly compatible with nanopore data with a high frequency resolution. To provide proof-of-concept, we applied HHT to measure the frequency response for the wild-type (WT) aerolysin and mutant K238E aerolysin nanopores with and without the presence of poly(dA)4, respectively. The energy-frequency-time distribution spectra demonstrate that the biological nanopore contributes greatly to the characteristics of the high frequency component (>2 kHz) in the current recording. Our results suggest that poly(dA)4 undergoes relatively more consistent and confined interactions with K238E than WT, leading to a prolonging of the duration time. Therefore, the characteristics in frequency analysis could be regarded as an "single-molecule ionic spectrum" inside the nanopore, which encodes the detailed behaviours of single-molecule weak interactions.
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In pursuit of sustainable aquaculture, this study was performed to evaluate chicken meal as a substitute for fishmeal in bullfrog diets. Three experimental groups were established: a control group (FM) with 20% fishmeal, a CM50 group with 50% replacement (10% fishmeal), and a CM100 group with 100% replacement (0 fishmeal). Bullfrogs were fed for 56 days. The CM50 group exhibited significant increases in total weight gain and survival rate and a notable decrease in feed coefficient (p < 0.05). However, the CM100 group showed contrary effects. Increasing chicken meal substitution correlated with decreased amino acid content in muscle. Notably, the CM50 group demonstrated enhanced activities of antioxidant enzymes (CAT, T-AOC) and elevated gene expression levels (cat, sod, gst, etc.) in muscle and the intestine (p < 0.05), improved intestinal morphology, enhanced digestive enzyme activities (amylase, lipase), and reduced expression of inflammatory factors (il-1ß, il-8, il-17, etc.). Conversely, the CM100 group's indicators regressed to levels similar to or worse than those of the FM group. Therefore, a 50% substitution of fishmeal with chicken meal effectively promoted bullfrog survival, protected the intestines, and enhanced antioxidant capacity, supporting its potential as a fishmeal alternative. However, the adverse outcomes of the CM100 strategy, including growth retardation and reduced amino acid content in muscle, indicate that complete replacement is unsuitable.
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A low metamorphosis rate of amphibian larvae, commonly known as tadpoles, limits the farming production of bullfrogs (Lithobates catesbeiana). This study aimed to examine the effects of processed thyroid powder as a feed additive on tadpole metamorphosis, lipid metabolism, and gut microbiota. Five groups of tadpoles were fed with diets containing 0 g/kg (TH0), 1.5 g/kg (TH1.5), 3 g/kg (TH3), 4.5 g/kg (TH4.5), and 6 g/kg (TH6) thyroid powder for 70 days. The results showed that TH increased the average weight of tadpoles during metamorphosis, with the TH6 group having the highest values. The TH4.5 group had the highest metamorphosis rate (p < 0.05). Biochemical tests and Oil Red O staining showed that the lipid (triglyceride) content in the liver decreased after TH supplementation, especially at doses higher than 1.5 g/kg. RT-qPCR revealed that TH at doses higher than 4.5 g/kg significantly up-regulated the transcriptional expression of the pparα, accb, fas, fadd6, acadl, and lcat genes, which are related to lipid metabolism (p < 0.05). These results showed that TH seems to simultaneously promote the synthesis and decomposition of lipid and fatty acids, but ultimately show a decrease in lipids. As for the gut microbiota, it is noteworthy that Verrucomicrobia increased significantly in the TH4.5 and TH6 groups, and the Akkermansia (classified as Verrucomicrobia) was the corresponding genus, which is related to lipid metabolism. Specifically, the metabolic pathways of the gut microbiota were mainly enriched in metabolic-related functions (such as lipid metabolism), and there were significant differences in metabolic and immune pathways between the TH4.5 and TH0 groups (p < 0.05). In summary, TH may enhance lipid metabolism by modulating the gut microbiota (especially Akkermansia), thereby promoting the growth of tadpoles. Consequently, a supplementation of 4.5 g/kg or 6 g/kg of TH is recommended for promoting the metamorphosis and growth of tadpoles.
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Background: Patients undergoing chemotherapy often encounter troubling and common side effects, notably Chemotherapy-induced nausea and vomiting (CINV). This side effect not only impairs the patient's quality of life but could also result in the interruption or discontinuation of the chemotherapy treatment. Consequently, research into CINV has consistently remained a focal point in the realm of clinical medicine. In this research domain, bibliometric analysis has not been conducted. The purpose of this study is to deliver a thorough summary of the knowledge framework and key areas of interest in the field of Chemotherapy-induced nausea and vomiting, using bibliometric methods. This approach aims to furnish novel concepts and pathways for investigators working in this area. Methods: Publications focusing on Chemotherapy-induced nausea and vomiting, spanning from 2004 to 2023, were identified using the Web of Science Core Collection (WoSCC) database. Tools such as VOSviewer, CiteSpace, and the R package "bibliometrix" were employed for this bibliometric analysis. Results: This research covers 734 publications from 61 countries, with the United States and China being the primary contributors. There has been a significant rise in the volume of papers published in the most recent decade compared to the one before it, spanning over the past twenty years. However, the annual publication rate in the last ten years has not shown a significant upward trend. The University of Toronto, Merck & Co., Sun Yat-sen University, and Helsinn Healthcare SA emerged as the principal research institutions in this field. Supportive Care in Cancer stands out as the most frequently published and cited journal in this domain. These works are contributed by 3,917 authors, with Rudolph M Navari, Matti Aapro, Shimokawa Mototsugu, and Lee Schwartzberg being among those who have published the most. Paul J. Hesketh is notably the most co-cited author. The primary focus of this research field lies in exploring the mechanisms of CINV and the therapeutic strategies for managing it. Key emerging research hotspots are represented by terms such as "Chemotherapy-induced nausea and vomiting," "nausea," "vomiting," "chemotherapy," and "antiemetics." Conclusion: This represents the inaugural bibliometric study to thoroughly outline the research trends and advancements in the field of CINV. It highlights the latest research frontiers and trending directions, offering valuable insights for scholars engaged in studying CINV.
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We developed a bipolar SiNx nanopore for the observation of single-molecule heterogeneous enzymatic dynamics. Single glucose oxidase was immobilized inside the nanopore and its electrocatalytic behaviour was real-time monitored via continuous recording of ionic flux amplification. The temporal heterogeneity in enzymatic properties and its spatial dynamic orientations were observed simultaneously, and these two properties were found to be closely correlated. We anticipate that this method offers new perspectives on the correlation of protein structure and function at the single-molecule level.
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Nanoporos , Proteínas/química , Glucose Oxidase , Nanotecnologia , ÍonsRESUMO
The thermal degradation kinetics and degradation products of IPBC during the heating process are investigated herein. Experiments were conducted at isothermal conditions from 60 °C to 150 °C. The remaining IPBC content was analyzed by high-performance liquid chromatography (HPLC) at specific time intervals for each test, and the kinetic model of IPBC thermal degradation was established. The thermal degradation products of IPBC were studied by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS/MS). The results showed that thermal degradation of IPBC occurred at 70 °C, and the degradation rate increased significantly from 70 °C to 150 °C. The thermal degradation kinetics of IPBC conformed to the first-order reaction and k=3.47×1012e-111125/RT from 60 °C to 150 °C. Seven degradation products such as prop-2-yn-1-yl ethylcarbamate and methyl N-butylcarbamate were identified and the degradation reaction pathway and the mechanism of IPBC were proposed, which involved deiodination, demethylation, deethynylation, deethylation, and hydroxylation processes.
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An 8-week feeding trial with high-carbohydrate- and 100, 200 and 300 mg/kg mulberry leaf flavonoids (MLF)-supplemented diets (HCF1, HCF2 and HCF3, respectively) was conducted to evaluate the protective effect of MLF on oxidized high-carbohydrate-induced glucose metabolism disorder, liver oxidative damage and intestinal microbiota disturbance in Monopterus albus. The results showed that HC diets had significant negative effects on growth, glucose metabolism, liver antioxidant and immunity, as well as intestinal microbiota, in comparison to CON diets. However, WGR and SR in the HCF3 group dramatically increased compared to the HC group. With the increase of MLF in the HC diet, the activities of glycolysis and antioxidant enzymes in the liver tended to increase, while the changes of gluconeogenesis-related enzyme activities showed the opposite trend and significantly changed in the HCF3 group. Additionally, MLF supplementation dramatically increased the mRNA expression involved in glycolysis, antioxidative enzymes and anti-inflammatory cytokines in comparison with the HC group. Furthermore, gluconeogenesis and pro-inflammatory cytokine genes' expression dramatically decreased. Furthermore, the proportion of Clostridium and Rhodobacter in the HC group dramatically declined, and the proportion of Lactococcus dramatically increased, compared to the HC group. In addition, 300 mg/kg MLF supplementation significantly improved the species composition and homeostasis of intestinal microbiota. These results indicate that MLF can alleviate the negative effects of low growth performance, glucose metabolism disorder, liver oxidative damage and intestinal microbiota disturbance caused by HC diets, and the relief of MLF is dose-related.
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A fundamental question relating to protein folding/unfolding is the time evolution of the folding of a protein into its precisely defined native structure. The proper identification of transition conformations is essential for accurately describing the dynamic protein folding/unfolding pathways. Owing to the rapid transitions and sub-nm conformation differences involved, the acquisition of the transient conformations and dynamics of proteins is difficult due to limited instrumental resolution. Using the electrochemical confinement effect of a solid-state nanopore, we were able to snapshot the transient conformations and trace the multiple transition pathways of a single peptide inside a nanopore. By combining the results with a Markov chain model, this new single-molecule technique is applied to clarify the transition pathways of the ß-hairpin peptide, which shows nonequilibrium fluctuations among several blockage current stages. This method enables the high-throughput investigation of transition pathways experimentally to access previously obscure peptide dynamics, which is significant for understanding the folding/unfolding mechanisms and misfolding of peptides or proteins.
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Nanopore measurement has advanced in single-molecule analysis by providing a transient time and confined space window that only allows one interested molecule to exist. By optimization and integration of the electrical and optical analysis strategies in this transient window, the acquisition of comprehensive information could be achieved to resolve the intrinsic properties and heterogeneity of a single molecule. In this work, we present a roadmap to build a unified optical and electrochemical synchronous measurement platform for the research of a single molecule. We design a low-cost ultralow-current amplifier with low noise and high-bandwidth to measure the ionic current events as a single molecule translocates through a nanopore and combine a multi-functional optical system to implement the acquisition of the fluorescence, scattering spectrum, and photocurrent intensity of single molecule events in a nanopore confined space. Our system is a unified and unique platform for the protein nanopore, the solid-state nanopore, and the glass capillary nanopore, which has advantages in the comprehensive research of nanopore single-molecule techniques.
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Nanoporos , Dispositivos Ópticos , Eletricidade , NanotecnologiaRESUMO
Changes in the nanopore ionic current during entry of a target molecule underlie the sensing capability and dominate the intensity and extent of applications of the nanopore approach. The volume exclusion model has been proposed and corrected to describe the nanopore current blockage. However, increasing evidence shows nonconformity with this model, suggesting that the ionic current within a nanopore should be entirely reconsidered. Here, we revisit the origin of nanopore current blockage from a theoretical perspective and propose that the noncovalent interactions between a nanopore and a target molecule affect the conductance of the solution inside the nanopore, leading to enhanced current blockage. Moreover, by considering the example of an aerolysin nanopore discriminating the cytosine DNA and methylcytosine DNA that differ by a single methyl group, we completely demonstrate, by nanopore experiments and molecular dynamics simulations, the essential nature of this noncovalent interaction for discrimination. Our conductance model suggests multiplicative effects of both volume exclusion and noncovalent interaction on the current blockage and provides a new strategy to achieve volume difference sensing at the atomic level with highly specific current events, which would promote the nanopore protein sequencing and its applications in real-life systems.
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Nanofibrillated cellulose (NFC) as a natural macromolecule, binder, dispersant, enhancer, was utilized to facilitate the assembly of graphene sheets, imparting a steady stacked structure by the sheets to the electric heating membrane with flexibility and uniform heating performance. Strong interface bonding formed in the membrane, which combined graphene sheets to be a steady conductive network structure for electric heating. The membrane attained an equilibrium temperature rise to 60°C in 3min under 2000Wm-2, which increased linearly with increasing power density and graphene content. Decreased resistance between two electrodes was caused by electric-heat coupling effect which led to a decrease in the membrane's oxygen-containing groups as conducting electrification. The temperature distributing on membrane surface, and that as bent and distorted to different angles even simultaneously at the electric heating status, were all characterized by infrared thermal imaging to indicate the uniform distribution and well bonding performance between NFC and graphene, as well as the great flexibility in the biomass membrane. This study would further broaden the utilization of the natural nanocellulose-graphene biomass composites.
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Celulose/química , Eletricidade , Grafite/química , Temperatura Alta , Membranas Artificiais , Nanoestruturas/química , Biomassa , Cinética , Fenômenos Mecânicos , TemperaturaRESUMO
Single protein sensing based on solid-state nanopores is promising but challenging, because the fast translocation velocity of a protein is beyond the bandwidth of nanopore instruments. To decelerate the translocation speed, here, we employed a common protein cross-link interaction to achieve a general and robust nanopore sensing platform for single-molecule detection of protein. Benefiting from the EDC/NHS coupling interaction between nanopore and proteins, a 10-fold decrease in speed has been achieved. The clearly distinguishable current signatures further reveal that the anisotropic translocation of a protein, which are horizontal, vertical, and flipping transit inside nanopore confinement. This strategy provides a general platform for rapid detection of proteins as well as exploring fundamental protein dynamics at the single-molecule level.
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Nanotecnologia/instrumentação , Proteínas/análise , Glucose Oxidase/análise , Ouro/química , Porosidade , Succinimidas/químicaRESUMO
Wild-type aerolysin (AeL) nanopores allow direct single nucleotide discrimination of very short oligonucleotides (≤10 nt) without labelling, which shows great potential for DNA sensing. To achieve real applications, one major obstacle of AeL is its poor capture ability of long single-stranded DNA (ssDNA, >10 nt). Here, we have proposed a novel and robust strategy for the electrostatic focusing of long ssDNA into a lithium-chloride (LiCl)-active AeL. By using this method, for the first time we have demonstrated AeL detection of ssDNA longer than 100 nt. Due to screening more negative charges, LiCl improves AeL capture ability of long ssDNA (i.e. 60 nt) by 2.63- to 10.23-fold compared to KCl. Further calculations and molecular dynamics simulations revealed that strong binding between Li+ and the negatively charged residue neutralized the AeL, leading to a reduction in the energy barrier for ssDNA capture. These findings facilitate the future high-throughput applications of AeL in genetic and epigenetic diagnostics.
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Nanofibrillated cellulose (NFC) and graphene oxide (GO) with reinforcing and film-forming properties were employed with graphene to develop a novel and thin electric heating membrane with heat dissipation controllability. A negative charge was found on the surface of GO and NFC in aqueous dispersions, which contributed to the homogeneous distribution of the graphene sheets. The membrane had a good laminated structure with three-dimensional interaction between GO and NFC, with embedded graphene sheets. Conductivity was characterized as a function of the amount of graphene, thus giving control over to the heating power by adjusting the ratio of graphene. Subsequent electric heating tests can remove irregularities on the GO and graphene sheet, improving the laminated structure further. The temperature on the surface of the membrane presented an exponential increasing regularity with time. Under the same power density and time, the stabilized temperature rise of membranes was higher when grammage was higher, which was characterized by the linear function of the power density. Low-grammage membranes (1 and 4 g·m-2) also exhibited regular and even stabilized temperature rises. The indicated structure and heating performance of the membrane, as well as the variation induced by Joule heating, would drive its applications.