Simultaneous single-cell three-dimensional genome and gene expression profiling uncovers dynamic enhancer connectivity underlying olfactory receptor choice.

The simultaneous measurement of three-dimensional (3D) genome structure and gene expression of individual cells is critical for understanding a genome's structure-function relationship, yet this is challenging for existing methods. Here we present 'Linking mRNA to Chromatin Architecture (LiMCA)', which jointly profiles the 3D genome and transcriptome with exceptional sensitivity and from low-input materials. Combining LiMCA and our high-resolution scATAC-seq assay, METATAC, we successfully characterized chromatin accessibility, as well as paired 3D genome structures and gene expression information, of individual developing olfactory sensory neurons. We expanded the repertoire of known olfactory receptor (OR) enhancers and discovered unexpected rules of their dynamics: OR genes and their enhancers are most accessible during early differentiation. Furthermore, we revealed the dynamic spatial relationship between ORs and enhancers behind stepwise OR expression. These findings offer valuable insights into how 3D connectivity of ORs and enhancers dynamically orchestrate the 'one neuron-one receptor' selection process.

Fenton-like membrane reactor assembled by electron polarization and defect engineering modifying Co3O4 spinel for flow-through removal of organic contaminants.

The application of Fenton-like membrane reactors for water purification offers a promising solution to overcome technical challenges associated with catalyst recovery, reaction efficiency, and mass transfer typically encountered in heterogeneous batch reaction modes. This study presents a dual-modification strategy encompassing electron polarization and defect engineering to synthesize Al-doped and oxygen vacancies (OV)-enriched Co3O4 spinel catalysts (ACO-OV). This modification empowered ACO-OV with exceptional performance in activating peroxymonosulfate (PMS) for the removal of organic contaminants. Moreover, the ACO-OV@polyethersulfone (PES) membrane/PMS system achieved organic contaminant removal through filtration (with a reaction kinetic constant of 0.085 ms-1), demonstrating outstanding resistance to environmental interference and high operational stability. Mechanistic investigations revealed that the exceptional catalytic performance of this Fenton-like membrane reactor stemmed from the enrichment of reactants, exposure of reactive sites, and enhanced mass transfer within the confined space, leading to a higher availability of reactive species. Theoretical calculations were conducted to validate the beneficial intrinsic effects of electron polarization, defect engineering, and the confined space within the membrane reactor on PMS activation and organic contaminant removal. Notably, the ACO-OV@PES membrane/PMS system not only mineralized the targeted organic contaminants but also effectively mitigated their potential environmental risks. Overall, this work underscores the significant potential of the dual-modification strategy in designing spinel catalysts and Fenton-like membrane reactors for efficient organic contaminant removal.

Photocatalytic O2 activation by metal-free carbon nitride nanotube for rapid reactive species generation and organic contaminants degradation.

Advanced oxidation processes (AOPs) using oxygen (O2) as an oxidant represent a low-cost and sustainable wastewater treatment process. Herein, a metal-free nanotubular carbon nitride photocatalyst (CN NT) was prepared to activate O2 to degrade organic contaminants. The nanotube structure allowed for sufficient O2 adsorption, while the optical and photoelectrochemical properties enabled photogenerated charge to be efficiently transferred to the adsorbed O2 to trigger the activation process. The developed CN NT/Vis-O2 system based on O2 aeration degraded various organic contaminants and mineralized 40.7% of chloroquine phosphate within 100 min. In addition, the toxicity and environmental risk of treated contaminants were reduced. Mechanistic studies suggested that the enhanced O2 adsorption capacity and fast charge transfer behavior on CN NT surface led to reactive·O2-, 1O2 and h+ generation, each of which played a distinct role in contaminants degradation. Importantly, the proposed process could overcome the interference from water matrices and outdoor sunlight, and the energy and chemical reagent savings reduced the operating cost to about 1.63 US$·m-3. Altogether, this work provides insights into the potential application of metal-free photocatalysts and green O2 activation for wastewater treatment.

Insights into the characteristics, adsorption and desorption behaviors of microplastics aged with or without fulvic acid.

Many aging experiments on microplastics (MPs) have been carried out using UV radiation or strong oxidants. Little attention has been paid to the role of water environmental factors such as dissolved organic matter (DOM). In this study, the role of fulvic acid (FA), the main component of DOM, in the UV-aging process of MPs was explored. MPs aged under UV, and UV along with 0.5 mg/L and 2 mg/L FA, were selected as subjects. The results showed that (1) FA accelerated the aging process of polyethylene (PE). PE aged with FA had a larger specific area (SBET), with more holes and cracks on the surface. (2) FA enhanced the adsorption capacity of PE. The TC adsorption quantities of 0, 0.5, and 2 mg/L FA-aged PE were 1.100, 1.447, and 1.812 mg/L, respectively. (3) The quantity of TC desorbed by PE increased, whereas the desorption rate decreased as the FA concentration increased. The desorption rates of TC at 0, 0.5, and 2 mg/L FA-aged PE were 25.16%, 22.05%, and 19.52% in water, and 72.10%, 70.36%, and 59.51% in simulated intestinal fluid. This study explored the role of FA in the aging process of MPs. Moreover, research on the aging mechanism of MPs is enriched.

An Investigation on Energy Harvesting Behavior of an Array Piezoelectric Coupled Disc Damper.

In order to make full use of the vibration energy in the process of attenuating vibration, an array piezoelectric coupled disc damper is developed, which works by converting part vibration energy into electrical energy. The piezoelectric damper is made of a pair of piezoelectric coupled discs built in a case cylinder. Its energy harvesting behavior is studied by a series of forced-vibration experiments and simulations. The influences of some factors, such as the excitation frequency, substrate thickness, the size of the piezoelectric patch, the paste form of the piezoelectric patch and the load resistance, on the energy harvesting behavior of the damper are analyzed and concluded. The experimental results show that the maximum peak-to-peak voltage and average power from one piezoelectric patch with an inner diameter of 35 mm, an outer diameter of 80 mm, and a thickness of 1 mm can reach up to 163 V and 161 mW, respectively. This research provides a practical piezoelectric damper attenuating harmful vibration by converting them into useful electric power, and the corresponding theoretical models are derived to predict its electrical output.

Optimization of PNP Degradation by UV-Activated Granular Activated Carbon Supported Nano-Zero-Valent-Iron-Cobalt Activated Persulfate by Response Surface Method.

Nitrophenols are toxic substances that present humans and animals with the risk of deformities, mutations, or cancer when ingested or inhaled. Traditional water treatment technologies have high costs and low p-nitrophenol (PNP) removal efficiency. Therefore, an ultraviolet (UV)-activated granular activated carbon supported nano-zero-valent-iron-cobalt (Co-nZVI/GAC) activated persulfate (PS) system was constructed to efficiently degrade PNP with Co-nZVI/GAC dosage, PS concentration, UV power, and pH as dependent variables and PNP removal rate as response values. A mathematical model between the factors and response values was developed using a central composite design (CCD) model. The model-fitting results showed that the PNP degradation rate was 96.7%, close to the predicted value of 98.05 when validation tests were performed under Co-nZVI/GAC injection conditions of 0.827 g/L, PS concentration of 3.811 mmol/L, UV power of 39.496 W, and pH of 2.838. This study demonstrates the feasibility of the response surface methodology for optimizing the UV-activated Co-nZVI/GAC-activated PS degradation of PNP.

Unique characteristics of G719X and S768I compound double mutations of epidermal growth factor receptor (EGFR) gene in lung cancer of coal-producing areas of East Yunnan in Southwestern China.

BACKGROUND: The principal objective of this project was to investigate the Epidermal Growth Factor Receptor (EGFR) gene mutation characteristics of lung cancer patients, which can provide a molecular basis for explaining the clinicopathological features, epidemiology and use of targeted therapy in lung cancer patients in the coal-producing areas of East Yunnan. METHODOLOGY: We collected 864 pathologically confirmed lung cancer patients' specimens in First People's Hospital of Qujing City of Yunnan Province from September 2016 to September 2021. We thereafter employed Next Generation Sequencing (NGS) technology to detect all exons present in the EGFR gene. RESULTS: The overall mutation frequency of the EGFR gene was 47.22%. The frequency of EGFR gene mutations in the tissue, plasma, and cytology samples were found to be 53.40%, 23.33%, and 62.50%, respectively. Univariate analysis indicated that the coal-producing areas and Fuyuan county origin were significantly associated with relatively low EGFR gene mutation frequency. Female, non-smoking history, adenocarcinoma, non-brain metastasis, and tissue specimens were found to be related to high EGFR gene mutation frequency. Multivariate logistic regression analysis suggested the lung cancer patients in the central area of Qujing City, stage Ia, non-coal-producing areas, non-Fuyuan origin, and non-Xuanwei origin were more likely to develop EGFR gene mutations. The most common mutations were L858R point mutation (33.09%) and exon 19 deletion (19-del) (21.32%). Interestingly, the mutation frequency of G719X (p = 0.001) and G719X + S768I (p = 0.000) in the coal-producing areas were noted to be more significant than those in non-coal-producing regions. CONCLUSION: This findings of this study might be important in establishing the correlation between routine using NGS for EGFR gene mutation diagnosis and clinical practice in the lung cancer patients.

OLA1 promotes colorectal cancer tumorigenesis by activation of HIF1α/CA9 axis.

BACKGROUND: Obg-like ATPase 1 (OLA1) is a highly conserved GTPase, which was over expressed in a variety of malignant tumors, but its role in colorectal cancer (CRC) was poorly studied. PATIENTS AND METHODS: Three public CRC gene databases were applied for OLA1 mRNA expression detection. The clinical data of 111 CRC patients were retrospectively collected from the Second Affiliated Hospital of Zhejiang University (SAHZU) for OLA1 protein expression and Kaplan-Meier Survival analysis. OLA1 stably knocked out CRC cell lines were conducted by CRISPR-Cas9 for experiments in vitro and in vivo. RESULTS: OLA1 was highly expressed in 84% CRC compared to matched surrounding tissues. Patients with OLA1 high expression had a significantly lower 5-year survival rate (47%) than those with OLA1 low expression (75%). OLA1 high expression was an independent factor of poor prognosis in CRC patients. OLA1-KO CRC cell lines showed lower ability of growth and tumorigenesis in vitro and in vivo. By mRNA sequence analysis, we found 113 differential express genes in OLA1-KO cell lines, of which 63 were hypoxic related. HIF1α was a key molecule in hypoxic regulation. Further molecular mechanisms showed HIF1α /CA9 mRNA and/or protein levels were heavily downregulated in OLA1-KO cell lines, which could explain the impaired tumorigenesis. According to previous studies, HIF1α was a downstream gene of GSK3ß, we verified GSK3ß was over-activated in OLA1-KO cell lines. CONCLUSION: OLA1 was a new gene that was associated with carcinogenesis and poor outcomes in CRC by activation of HIF1α/CA9 axis, which may be interpreted by GSK3ß.

Ball milling biochar with ammonia hydroxide or hydrogen peroxide enhances its adsorption of phenyl volatile organic compounds (VOCs).

Pristine biochar (CN600), ball-milled biochar (CN600-BM), H2O2 modified BM-biochar (CN600-O), and NH4OH modified BM-biochar (CN600-N) derived from corn stalk were applied to adsorb phenyl volatile organic compounds (VOCs). H2O2 and NH4OH modification of BM-biochar significantly improved its physicochemical characteristics and adsorption abilities. The specific surface area of CN600-O increased 2.05 and 1.23 times compared to CN600 and CN600-BM, respectively; while CN600-N increased 2.41 and 1.45 times, respectively. In addition, the ball milled biochars, especially CN600-O, showed higher acidity and polarity than CN600. The VOC adsorption amount onto biochars was 10.96-130.21 mg/g. CN600-O and CN600-N had high uptake of the VOCs and reached 100.07-111.79 mg/g and 110.49-130.21 mg/g, respectively. CN600-N showed the best performance with P-xylene adsorption up to 130.21 mg/g. VOC adsorption onto the CN600-O and CN600-N were mainly governed by surface adsorption and associated with morphology characteristics of the biochars as well as VOC properties such as boiling point and molecular size. Five cycles of adsorption-desorption experiments showed that CN600-O and CN600-N had good reusability with the reuse efficiencies of 88.01 %-92.21 % and 92.19 %-95.39 %, respectively. The results indicate that O- and N-doped ball-milled biochars are promising in adsorption for effective and sustainable VOC removal.

EVmiRNA: a database of miRNA profiling in extracellular vesicles.

Extracellular vesicles (EVs), such as exosomes and microvesicles, acted as cell-to-cell communication vectors and potential biomarkers for diseases. microRNAs (miRNAs) are the most well studied molecules in EVs, thus a comprehensive investigation of miRNA expression profiles in EVs will be helpful to explore their functions and biomarkers. We curated 462 small RNA sequencing samples of EVs from 17 sources/diseases and constructed the EVmiRNA database (http://bioinfo.life.hust.edu.cn/EVmiRNA) to show the miRNA expression profiles. We found >1000 miRNAs expressed in these EVs and detected specific miRNAs for EVs of each source/disease. EVmiRNA provides three functional modules: (i) the miRNA expression profiles and the sample information of EVs from different sources (such as blood, breast milk etc.); (ii) the specifically expressed miRNAs in different EVs that would be helpful for biomarker identification; (iii) the miRNA annotations including the miRNA expression in EVs and TCGA cancer types, miRNA pathway regulations as well as miRNA function and publications. EVmiRNA has a user-friendly web interface with powerful browse and search functions, as well as data downloading. It is the first database focusing on miRNA expression profiles in EVs and will be useful for the research and application community of EV biomarker, miRNA function and liquid biopsy.

Intensive glucose control for critically ill patients: an updated meta-analysis.

This meta-analysis aims to update the evidence for the effects of intensive glucose control (IGC) on the outcomes among critically ill patients. We performed a systematic literature review from inception through December, 2017 by two independent authors by searching PubMed, EMBASE and Cochrane Library. Randomized clinical trials of the effects of IGC compared with conventional glucose control were selected. Random-effect models were applied to calculate summary relative risks (RRs) for the related outcomes. Of 4247 records identified, we abstracted data from 27 relevant trials for meta-analysis. Compared with patients receiving conventional glucose control (controls), patients with IGC did not have significantly decreased risk of short-term mortality (in-hospital mortality or intensive care unit (ICU) mortality) (RR 0.99, 95% CI 0.92-1.06) or 3- to 6-month mortality (RR 1.02, 95% CI 0.97-1.08). These results remained constant among different study settings including surgical ICUs, medical ICUs or mixed ICUs. Similarly, we also found that patients with IGC did not have significantly lower risk of sepsis (RR 1.00, 95% CI 0.89-1.11) or new need for dialysis (RR 0.97, 95% CI 0.84-1.11). However, patients with IGC had almost 4-fold increase in risk of hypoglycemia (RR 4.86, 95% CI 3.16-7.46). In conclusion, in this updated meta-analysis of published trials, critically ill patients receiving IGC were found to be at neutral risk for short-term or 3- 6-month mortality, risk of sepsis or new need for dialysis, but at higher risk of hypoglycemia.

Exploring Space Management Goals in Institutional Care Facilities in China.

Space management has been widely examined in commercial facilities, educational facilities, and hospitals but not in China's institutional care facilities. Poor spatial arrangements, such as wasted space, dysfunctionality, and environment mismanagement, are increasing; in turn, the occupancy rate is decreasing due to residential dissatisfaction. To address these problems, this paper's objective is to explore the space management goals (SMGs) in institutional care facilities in China. Systematic literature analysis was adopted to set SMGs' principles, to identify nine theoretical SMGs, and to develop the conceptual model of SMGs for institutional care facilities. A total of 19 intensive interviews were conducted with stakeholders in seven institutional care facilities to collect data for qualitative analysis. The qualitative evidence was analyzed through open coding, axial coding, and selective coding. As a result, six major categories as well as their interrelationships were put forward to visualize the path diagram for exploring SMGs in China's institutional care facilities. Furthermore, seven expected SMGs that were explored from qualitative evidence were confirmed as China's SMGs in institutional care facilities by a validation test. Finally, a gap analysis among theoretical SMGs and China's SMGs provided recommendations for implementing space management in China's institutional care facilities.

Polarization property changes of optical beam transmission in atmospheric turbulent channels.

We theoretically analyze and experimentally verify the performance of multiple polarization parameters in the presence of atmospheric turbulence for a terrestrial optical transmission. First, both the first- and second-moment characteristic of polarization parameters are derived based on the extended Huygens-Fresnel principle. Then, numerical simulations are presented for different propagating distances, optical source properties, and turbulent strengths. Finally, a series of well-designed experiments are carried out to verify the theory with turbulence-controlled conditions, where the polarization states are measured at two wavelengths, respectively. As a result, the theoretical predictions conform closely to the experimental data, and both show that with the increasing turbulent strength, the first-order moment of polarization parameters varies in different trends, while their second-order moment increases. The proposed approach is promising for building a comprehensive statistical model of polarization and improving the performance of a free-space optical communication link.

Adaptive threshold decision for on-off keying transmission systems in atmospheric turbulence.

This paper investigates an adaptive threshold decision (ATD) scheme without the knowledge of channel state information (CSI) for optical wireless communication (OWC). Based on the low-pass characteristic of atmospheric turbulence channels, a low-pass filter is designed for the received signals, and the filtered signal can be employed as decision threshold. Theoretical analyses show that performance of ATD is very close to that with perfect CSI. Monte Carlo simulations demonstrate that the proposed scheme shows only 0.0221dB signal-to-noise (SNR) loss at most with Rytov variance of 0.05 and SNR of 21dB. An indoor experiment results are presented, which match well with that of theoretical prediction. The scheme is simple and without CSI, hence the efficient scheme makes the real-time implementation of high-speed transmissions for OWC based on ATD feasible.

The rs1550117 A>G variant in DNMT3A gene promoter significantly increases non-small cell lung cancer susceptibility in a Han Chinese population.

In this study, we conducted a case-control study to explore the association between rs1550117 A>G variant of DNMT3A gene promoter and non-small cell lung cancer (NSCLC) susceptibility in a Han Chinese population. The genotyping of rs1550117 A>G variant was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and confirmed by sequencing. Allele G of rs1550117 was associated with an increased risk of NSCLC. Moreover, individuals carrying the GG genotypes had a higher risk to develop NSCLC than the AA and GA genotype carriers. Further stratified analysis showed that rs1550117 A>G was significantly related to age (> 60 years), male, smoking and drinking. In vivo detection of DNMT3A mRNA levels in NSCLC tissues and in vitro luciferase assays consistently showed that the allele G significantly decreased DNMT3A transcription. Additional functional analysis revealed that the increased binding affinity of transcription repressor SP1, which was associated with allele G of rs1550117, led to the significant decreased expression of DNMT3A. Collectively, our results propose a suppression role of DNMT3A in NSCLC development and emphasize the dual roles of DNMT3A in tumorigenesis.

Downregulation of miRNA-141 in breast cancer cells is associated with cell migration and invasion: involvement of ANP32E targeting.

MicroRNAs (miRNAs) regulate many cellular activities, including cancer development, progression, and metastasis. Some miRNAs are involved in breast cancer (BC) migration and invasion, thus affect patients' prognosis. Microarray analysis was performed to compare miRNA expression in BC tissues, and results confirmed by qPCR. BC cell migration and invasion were studied in vitro with MDA-MB-231 cells using microplate transwell assays. miRNA targeting was investigated using luciferase assays, qPCR, and Western blot analysis in cells with overexpression of miRNA mimics. Knockdown of miRNA targets was performed using target siRNA lentiviral infection. Results show that microRNA-141 (miR-141) was downregulated in breast cancer tumor tissues compared with matched surrounding tissues. Downregulation of miR-141 expression correlated with tumor stage, lymph node involvement, and expressions of PCNA, Ki67, and HER2. Overexpression of miR-141 inhibited BC cell proliferation, migration, and invasion in vitro. ANP32E gene was selected as one putative target for further studies based on results from in silico analysis. Results from a dual-luciferase reporter system suggested ANP32E as a direct target of miR-141. Overexpression of miR-141 downregulated ANP32E expression at both mRNA and protein levels in BC cells. Knockdown of ANP32E inhibited BC cell proliferation, migration, and invasion in vitro, mimicking the effect of the overexpression of miR-141. Our study revealed important roles miR-141 plays in BC growth and metastasis. Moreover, for the first time, we identified ANP32E as one of the miR-141 targets, and demonstrated its involvement in the regulation of cell proliferation, migration, and invasion.

The DNMT3B -579G>T Polymorphism Is Significantly Associated With the Risk of Gastric Cancer but not Lung Cancer in Chinese Population.

The -149C>T and -579G>T, 2 single nucleotide polymorphisms in de novo methyltransferase 3B gene promoter, have been previously reported to potentially alter the promoter activity and to influence cancer risk. However, the results from previous studies remain conflicting rather than conclusive. In view of this, we conducted a case-control study and then a meta-analysis to examine the association between these 2 single-nucleotide polymorphisms with risk of lung and gastric cancer in Chinese population. The genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism and confirmed by sequencing. In this case-control study, no significant association with lung or gastric cancer risk was observed for -149C>T, while -579G>T was significantly correlated with the risk of gastric cancer but not lung cancer. Moreover, haplotype analysis showed that haplotype -149T/-579 T, which carried the risk -579 T allele, significantly increased the susceptibility to gastric cancer. However, none of the haplotypes was associated with the risk of lung cancer. The following meta-analysis involved only Chinese population and further confirmed the significant association of -579G>T with gastric cancer but not lung cancer and suggested no significant association between -149C>T and risk of lung or gastric cancer. Collectively, DNMT3B -579G>T polymorphism is associated with gastric cancer risk in Chinese population, and the -579G>T may be used as a genetic biomarker to predict the risk of gastric cancer in Chinese population.

Heavy Metal Resistances and Chromium Removal of a Novel Cr(VI)-Reducing Pseudomonad Strain Isolated from Circulating Cooling Water of Iron and Steel Plant.

Three bacterial isolates, GT2, GT3, and GT7, were isolated from the sludge and water of a circulating cooling system of iron and steel plant by screening on Cr(VI)-containing plates. Three isolates were characterized as the members of the genus Pseudomonas on the basis of phenotypic characteristics and 16S rRNA sequence analysis. All isolates were capable of resisting multiple antibiotics and heavy metals. GT7 was most resistant to Cr(VI), with a minimum inhibitory concentration (MIC) of 6.5 mmol L-1. GT7 displayed varied rates of Cr(VI) reduction in M2 broth, which was dependent on pH, initial Cr(VI) concentration, and inoculating dose. Total chromium analysis revealed that GT7 could remove a part of chromium from the media, and the maximum rate of chromium removal was up to 40.8 %. The Cr(VI) reductase activity of GT7 was mainly associated with the soluble fraction of cell-free extracts and reached optimum at pH 6.0∼8.0. The reductase activity was apparently enhanced by external electron donors and Cu(II), whereas it was seriously inhibited by Hg(II), Cd(II), and Zn(II). The reductase showed a K m of 74 µmol L-1 of Cr(VI) and a V max of 0.86 µmol of Cr(VI) min-1 mg-1 of protein. The results suggested that GT7 could be a promising candidate for in situ bioremediation of Cr(VI).

MiRNA-15a mediates cell cycle arrest and potentiates apoptosis in breast cancer cells by targeting synuclein-γ.

BACKGROUND: Recent studies have indicated that microRNA-15a (miR-15a) is dysregulated in breast cancer (BC). We aimed to evaluate the expression of miR-15a in BC tissues and corresponding para-carcinoma tissues. We also focused on effects of miR-15a on cellular behavior of MDA-MB-231 and expression of its target gene synuclein-γ (SNCG). MATERIALS AND METHODS: The expression levels of miR-15a were analysed in BC formalin fixed paraffin embedded (FFPE) tissues by microarray and quantitative real-time PCR. CCK-8 assays, cell cycle and apoptosis assays were used to explore the potential functions of miR-15a in MDA-MB-231 human BC cells. A luciferase reporter assay confirmed direct targets. RESULTS: Downregulation of miR-15a was detected in most primary BCs. Ectopic expression of miR-15a promoted proliferation and suppressed apoptosis in vivo. Further studies indicated that miR-15a may directly interact with the 3'-untranslated region (3'-UTR) of SNCG mRNA, downregulating its mRNA and protein expression levels. SNCG expression was negatively correlated with miR-15a expression. CONCLUSIONS: MiR-15a has a critical role in mediating cell cycle arrest and promoting cell apoptosis of BC, probably by directly targeting SNCG. Thus, it may be involved in development and progression of BC.

Fully printed, rapid-response sensors based on chemically modified graphene for detecting NO2 at room temperature.

Reduced graphene oxide (RGO) has proven to be effective in trace gas detection at room temperature ambient conditions. However, the slow response-recovery characteristic is a major hurdle for the RGO-based gas sensors. Herein, we report a gravure-printed chemoresistor-type NO2 sensor based on sulfonated RGO (S-RGO) decorated with Ag nanoparticles (Ag-S-RGO). Large amounts of silver nanoparticles with an average particle size of 10-20 nm were uniformly assembled on flat S-RGO surfaces. The printed Ag-S-RGO sensor possesses a high sensitivity and fast response-recovery characteristic over NO2 concentrations ranging from 0.5 to 50 ppm. Upon exposure to 50 ppm NO2 at room temperature, the Ag-S-RGO sensor shows a sensitivity of 74.6%, a response time of 12 s and a recovery time of 20 s. In addition, the Ag-S-RGO sensors exhibit satisfactory flexibility with an almost constant resistance after 1000 bending cycles. The printed and high-performance Ag-S-RGO sensors described here will be a good prospect in environmental monitoring of NO2.