Search

A staggered strand exchange amplification (SSEA) method was developed by employing a DNA polymerase and two sets of forward and reverse primers arranged in tandem that invade the denaturation bubbles of double-stranded DNA.

The total detection time from DNA preparation was about 20 min. The LOD of the ASEA method was 25 CFU mL−1 of pure cultured V. parahaemolyticus. The enrichment time was significantly reduced to 3 h with a LOD of 18 CFU g−1 of spiked scallop meat.

A two-stage isothermal amplification method termed rolling cycle strand exchange amplification (RC-SEA) was established to accomplish ssRNA and dsDNA analysis using only one DNA polymerase in a single closed tube at a constant temperature.

SARS-CoV-2 detection process from sample to answer by using SCAN.

Nucleic acid amplification tests (NAATs) have become an attractive approach for pathogen detection, and obtaining high-quality nucleic acid extracts from biological samples plays a critical role in ensuring accurate NAATs. In this work, we established an elution-free magnetic bead (MB)-based method by introducing polyethylene-polypropylene glycol (PEPPG) F68 in lysis buffer and using NaOH solution instead of alcohols as the washing buffer for rapid nucleic acid extraction from multiple types of biological samples, including nasopharyngeal swabs, serum, milk, and pork, which bypassed the nucleic acid elution step and allowed the nucleic acid/MB composite to be directly used as the template for amplification reactions. The entire extraction process was able to be completed in approximately 7 min. Even though the nucleic acid/MB composite could not be used for quantitative real-time PCR (qPCR) assays, this elution-free MB-based method significantly improved the sensitivity of the loop-mediated isothermal amplification (LAMP) assay. The sensitivity of the quantitative real-time LAMP (qLAMP) assays combined with this elution-free MB-based method showed an improvement of one to three orders of magnitude compared with qLAMP or qPCR assays combined with the traditional MB-based method. In addition to manual operation, like the traditional MB-based method, this universal, rapid, and facile nucleic acid extraction method also has potential for integration into automated robotic processing, making it particularly suitable for the establishment of an analysis platform for ultrafast and sensitive pathogen detection in various biological samples both in centralized laboratories and at remote sites.

Analysis of microRNAs (miRNAs) is important in cancer diagnostics and therapy. Conventional methods used to extract miRNA for analysis are generally time-consuming. A novel approach for rapid and sensitive extraction of miRNAs is urgently need for clinical applications. Herein, a novel strategy based on electrical potential-assisted DNA-RNA hybridization was designed for miRNA extraction. The entire extraction process was accomplished in approximately 3 min, which is much shorter than the commercial adsorption column method, at more than 60 min, or the TRIzol method, at more than 90 min. Additionally, the method offered the advantages of simplicity and specificity during the extraction process by electrical potential-assisted hybridization of single-stranded DNA and RNA. Taking let-7a as an example, satisfactory results were achieved for miRNA extraction in serum, demonstrating the applicability in miRNA nucleic acid amplification.

Respiratory tract infections caused by Mycoplasma pneumoniae is a serious risk for child health. It has been difficult to prevent and control for a variety of reasons; therefore, timely diagnosis is particularly important for treatment of patients. At present, the rapid M pneumoniae test kits based on nucleic acid amplification have been commercialized and used as primary diagnostic tools for M pneumoniae infection, but current kits are time-consuming, which is difficult to meet the requirement for accurate and rapid diagnosis of M pneumoniae during epidemics. Rapid and accurate test kits are urgently required to diagnose M pneumoniae infection. In this article, we evaluated the performance of a novel nucleic acid detection kit (A) for M pneumoniae from feasibility and sensitivity, and compared it with kit B. Results showed this kit has the advantage of being rapid, sensitive, and specific, which meets the demands for the diagnosis of M pneumoniae infection in clinical settings.

Salmonella is one of the most common pathogens associated with food-borne illness resulting from seafood consumption.

Herein, we developed an ultra-fast and visual single-tube nucleic acid detection approach, which combined the advantages of self-settling characteristics of chitosan-functionalized diatomaceous earth (CDE) and accelerated PCR (AC-PCR). DNA was rapidly extracted by CDE within 3 min for the next nucleic acid amplification based on the nucleic acid attached on the chitosan in pH = 5.0. Under the action of gravity, the DNA-enriched CDE self-sediments to the bottom of the tube could be directly used for AC-PCR to achieve single-tube extraction and amplification. Our method detected Salmonella culture fluids with a detection limit of 1 CFU/mL, which was 100-fold more sensitive than conventional method that have not undergone nucleic acid enrichment. Furthermore, it also displayed high specificity and sensitivity for a variety of spiked samples. The entire process could be completed within 17 min in a single tube, and in particular, the result was visualized by the naked eyes. Overall, it is an all-in-one detection strategy without the requirement of redundant procedure, which greatly improved the detection efficiency, and saved the time and the cost. With these advantages, the approach will supply a promising tool in the field of point-of-care testing for Salmonella and other foodborne pathogens. Supplementary Information The online version contains supplementary material available at 10.1007/s00216-022-03904-z.

Background To investigate the role of neutrophils in the regeneration of corneal nerve injury. Methods A mouse model of a corneal nerve injury was established, samples from with and without neutrophil closure in corneal scraping were collected for corneal nerve staining, RNA sequencing, and bioinformatics. Differential expression analysis between these two groups was performed for enrichment analysis. The differential genes were then intersected with neutrophil-associated genes, and the obtained intersected genes were subjected to protein-protein interaction (PPI) network construction. The immune infiltration between the two groups was observed as well as the variation of immune cells between the high and low gene expression groups. Results Removal of neutrophils delays the regeneration of corneal epithelium and nerves. A total of 546 differential genes and 980 neutrophil-associated genes, with 27 genes common to both were obtained. Molecular complex assay (MCODE) analysis yielded five key genes, ITGB2, MMP9, EGF, SERPINE1, and PLAUR. ITGB2, SERPINE1, and PLAUR demonstrated increased high expression in the neutrophil-confined group and decreased expression of MMP9 and EGF, and the difference was more significant for MMP9 and EGF. The immune infiltration was also observed between the two groups. The infiltration of M0 macrophages activated mast cells, and neutrophils were significantly different between the two groups. The levels of neutrophils were also shown to be lower in the MMP9 and EGF low expression groups and higher in the high expression group. Conclusion Neutrophil confinement may significantly affect the expression levels of MMP9 and EGF. Strategies to inhibit MMP9 may have potential therapeutic benefits.

Soil testing and formulated fertilization technology can effectively solve the problem of the excessive and inefficient use of chemical fertilizers. Previous studies have found that the use of the Internet can increase the adoption of soil testing and formulated fertilization technology among farmers. However, they do not distinguish between the effects of the different uses of the Internet (with or without productive use) on the adoption of soil testing and formulated fertilization technology. This study investigates the Internet use of 5341 professional farmers in rural China in 2019, finding that 18.97% of them still use the Internet for only communication and entertainment and do not use any agricultural productive services on the Internet. The adoption rate of soil testing and fertilization technology among these farmers is only 23.77%, which is approximately 10 percentage points lower than that of farmers who use the Internet for productive purposes. The double robust model shows that the probability of the adoption of soil testing and formulated fertilization technology by farmers with productive use of the Internet increases by six percentage points, which is both statistically and economically significant. In the future, China should train more farmers to use the Internet for productive purposes; this will help more farmers, particularly those with low skills and low educational attainment, to use the Internet and play a positive role in promoting the Internet for green agricultural production techniques.

Based on work passion model and the substitutes for leadership perspectives, this study examines the process linking abusive supervision to employee creativity by focusing on the mediating influence of employees' passion for inventing and the moderating influence of financial incentives and innovative culture. Data were obtained from 191 subordinates and their direct supervisor in China. We tested hypotheses using hierarchical multiple regression analyses. The results revealed that abusive supervision was negatively related to employee creativity, and employees' passion for inventing mediated the relationship between abusive supervision and employee creativity. Furthermore, financial incentives weakened the negative relationship between abusive supervision and employees' passion for inventing, while innovative culture could not change the above relationship. This study enriches the understanding of how abusive supervision is related to employee creativity by introducing the emotional mechanism and provides practical implications for reducing the harm of abusive supervision.

Aerobic glycolysis is the most classical pathway in tumor metabolic reprogramming. Aerobic glycolysis has been found in several studies to have an essential role in lung adenocarcinoma progression. Interleukin 37 (IL-37) has an important protective role in lung cancer. The mechanism by which glycolysis in lung adenocarcinoma is affected by IL-37 has not been clarified. Using qRT-PCR and western blot, we uncovered that GLUT1 expression was significantly higher in A549 cells than in BEAS-2B cells. GLUT1 expression was decreased in A549 cells treated with rhIL-37. Also, glucose uptake and lactic acid production were significantly reduced in A549 cells treated with 6uM BAY-876 (GLUT1 specific inhibitor). GLUT1 expression in A549 cells in this study was not inhibited by intracellular overexpression of IL-37. Glucose uptake and lactic acid production may be inhibited by extracellular IL-37 by inhibiting GLUT1 expression. Therefore, IL-37 has a role in glucose metabolism in lung adenocarcinoma cells.

RNA isolation from bacteria is technically difficult due to the RNA characteristic of labile and vulnerable degradation. Many reagents were explored for cellular lysis and complete inhibition of RNase. However, the available methods for RNA isolation are either of low efficiency or time-consuming. Here, we developed a rapid and accessible protocol for RNA isolation that combined a simplified cell lysis and RNA release by formamide-based solution and RNA purification by chitosan-modified silica membrane for the first time. With this method, we obtained about ~ 28 μg of total RNA from 108 Escherichia coli cells. The entire procedure can be done within 15 min without redundant pipetting steps. The purity of extracted RNA was comparable to that of commercial kits, but the cost was much lower. Furthermore, the yielded RNA was successfully used in downstream enzymatic reactions, such as reverse transcription and quantitative real-time PCR. This new method would be of benefit for an extensive range of gene expression analyses in bacterial organisms.

Endophytic bacteria from legume roots and nodules play important roles in regulating plant growth and health. Therefore, the aim is to focus on the community structure and network of pea root endophytes throughout the plant life cycle. We collected five edible pea cultivars to study the endophytic bacterial community during the whole developmental period using Illumina sequencing of 16S rRNA gene. The structure and complexity of root endophytes was significantly affected by the development period and different root endophytes were recruited by peas at different developmental stages. Pea cultivars gave no significant influence on the patterns of root endophytic bacterial community during plant growth. Here, the complexity of root-endophytic bacterial community was the highest at seedling stage and became more and more simple after that. Rhizobium was a dominant root bacteria during the whole developmental stage. The amount of Rhizobium began to accumulate in pea seedling roots, and reached the highest at flowering stage and decreased at the mature stage. The relative abundance of Pseudomonas increased overtime throughout the pea entire life cycle, whereas the amount of Bacteroides decreased overtime. The pea root and nodule endophytes were dominated by Rhizobium, Pseudomonas and Bacteroides. These findings provide an endophyte-based characterization of the reference stock bacteria detail for the establishment of root endophytic bacteria throughout the plant life cycle. Specially, a proper synthetic microbial community to improve pea yields.

The false-negative result of nucleic acid testing is an important cause of continued spread of COVID-19, while SARS-CoV-2 RNA degradation during transportation and nucleic acid extraction can lead to false-negative results. Here, we investigated that single-walled carbon nanotubes (SCNTs) could protect RNA from degradation for at least 4 days at room temperature. By constructing magnetism-functionalized SCNTs (MSCNTs), we developed a method that enabled protection and simple extraction of SARS-CoV-2 RNA, and the RNA-bound MSCNTs can be directly used for reverse transcription polymerase chain reaction (RT-qPCR) detection. The experimental results showed that 1 μg of MSCNTs adsorbed up to 24 ng of RNA. Notably, the MSCNTs-based method for extracting SARS-CoV-2 RNA from simulated nasopharyngeal swabs and saliva samples with mean recovery rates of 103% and 106% improved the sensitivity of RT-qPCR detection by 8-32 fold in comparison to current common methods. This improvement was largely attributable to the protection of RNA, enabling increased RNA load for downstream assays.

Lung cancer remains the leading cause of cancer morbidity and mortality worldwide, and over diagnosis causes various unnecessary losses in patients' lives and health. How to more effectively screen lung cancer patients and their potential prognostic risk become the focus of our current study. By analyzing the LUAD expression profile in The Cancer Genome Atlas (TCGA), we constructed a weighted gene co-expression network using differentially expressed genes (DEGs) to find the key modules and pivotal genes. A COX proportional risk regression model based on the least absolute shrinkage and selection operator (LASSO) was used to assess the predictive value of the model for the prognosis of LUAD patients. A total of 4107 up-regulated DEGs and 2022 down-regulated DEGs were identified in this study, and enrichment analysis showed that these analyzes were associated with the extracellular matrix of cells and adhesion. Ten gene markers consisting of LDHA, TOP2A, UBE2C, TYMS, TRIP13, EXO1, TTK, TPX2, ZWINT, and UHRF1 were established by extracting the central genes in the key modules, and the upregulation of these genes was accompanied by an increased prognostic risk of patients. Among them, high expression of LDHA, TRIP13, TTK in LUAD was associated with shorter overall survival and could be used as independent prognostic factors to participate in metabolic processes such as tumor NAD. The present study provides a powerful molecular target for the study of LUAD prognosis and provides a theoretical basis for the diagnosis and treatment of LUAD and the development of targeted inhibitors.

Zike Sheng,1,&ast; Junjie Li,2,&ast; Tingting Chen,3 Yan Zhu,4 Xueping Yu,5 Xiuhua He,5 Yijuan Zheng,5 Cuiping Ma,6 Minghui Zheng,5 Peiyun Wang,1 Ziqiang Li,1 Yumin Xu,7 Qing Xie,1 Zhijun Su,5 Sumei Chen5 1Department of Infectious Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People’s Republic of China; 2Department of Respiratory and Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People’s Republic of China; 3Department of Pharmacy, The First Hospital of Quanzhou Affiliated to Fujian Medical University, Quanzhou, People’s Republic of China; 4Clinical Laboratory, The First Hospital of Quanzhou Affiliated to Fujian Medical University, Quanzhou, People’s Republic of China; 5Department of Infectious Diseases, The First Hospital of Quanzhou Affiliated to Fujian Medical University, Quanzhou, People’s Republic of China; 6Department of Infection Control, The First Hospital of Quanzhou Affiliated to Fujian Medical University, Quanzhou, People’s Republic of China; 7Department of Infection Control, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Zhijun Su; Sumei Chen, Department of Infectious Diseases, The First Hospital of Quanzhou Affiliated to Fujian Medical University, Licheng District, Quanzhou, People’s Republic of China, Tel +86-595-22277011 ; +86-595-22277173, Fax +86-595-222781, Email su2366@sina.com; chensm561119190@sina.comPurpose: Hypervirulent Klebsiella pneumoniae (hvKP) is emerging globally and can cause various infections. This study aimed to investigate the clinical and microbiological characteristics of bloodstream infection (BSI) caused by hvKP.Patients and Methods: The clinical data of hospitalized patients with K. pneumoniae BSI were retrospectively analyzed. The K. pneumoniae strains were collected and re-identified, and antimicrobial susceptibility testing was performed using the broth microdilution method. Capsular serotypes and virulence genes were detected using polymerase chain reaction, and hvKP was defined as aerobactin positive. Molecular typing was done by multilocus sequence typing. The hvKP and classic K. pneumoniae (cKP) subgroups were compared.Results: Of the 66 nonrepetitive BSI K. pneumoniae strains included, 29 (43.9%) were hvKP. In these BSI hvKP strains, salmochelin and yersiniabactin accounted for 86.2% and 72.4%, respectively. The prevalence of rmpA, iroBCD cluster, ybtS, clbA, and allS was 89.7%, 86.2%, 72.4%, 51.7%, and 41.4%, respectively, which were all significantly different between the hvKP and cKP subgroups. Serotypes K1 and K2 were strongly associated with hypervirulence (P < 0.05). Nineteen sequence types were scattered in the 29 hvKP strains, and the most common was ST23 (24.1%). None of the hvKP strains were carbapenem resistant. Compared with cKP, hvKP was more capable of developing a liver abscess. However, the 30-day mortality rate was lower (13.8% vs 21.6%) in the hvKP subgroup than in the cKP subgroup.Conclusion: This study demonstrated a high proportion of hvKP in BSI K. pneumoniae, most of which were RmpA and siderophore producing, and of multiclonal origin.Keywords: capsular serotypes, hypervirulence, infection, mortality, sequence type

Herein, we developed a facile integrated Mycoplasma pneumoniae diagnosis platform by combining amino-modified silica membrane (AMSM)-based nucleic acids fast extraction and enrichment with colorimetric isothermal amplification detection. AMSM demonstrates a strong ability to capture and enrich nucleic acids in complicated biological matrices, and the purified AMSM/nucleic acids composite could be directly used to perform isothermal amplification including denaturation bubble-mediated strand exchange amplification (SEA) and loop-mediated isothermal amplification (LAMP) reactions. Through comparing clinical specimens, excellent performance of AMSM-based SEA assay with 93.33% sensitivity and 100% specificity relative to real-time PCR was observed, and for AMSM-based LAMP was 96.67% and 100%, respectively. The diagnostic procedure could be completed within 55 min, and the colorimetric-based visual result further alleviates the use of sophisticated equipment. The proposed approach possesses great potential as a simple and time-saving alternative for point-of-care testing (POCT) of M. pneumoniae in resource-limited regions.

Exosomes are emerging as one of the most promising biomarkers for early disease diagnosis and prognosis. The significant challenges facing the available methods include improving the detection specificity and sensitivity in complex biological samples. Herein, a fluorescence assay was established based on a combination of immunomagnetic separation and a two-step signal amplification strategy for direct isolation and subsequent detection of exosomes. First, immunomagnetic beads capture and enrich the exosomes via antibody-antigen reactions. Second, bivalent cholesterol (BC) anchors spontaneously insert into the lipid bilayer of bead-captured exosomes, forming a "one to many" amplification effect. The simultaneous recognition of the surface protein and the lipid bilayer structure of the exosome significantly eliminates the interference risk from free proteins. The detection of exosomes converts to the detection of BC-anchors. Finally, the sticky end of the BC-anchor acts as the initiator to trigger the enzyme-free DNA circuits for secondary signal amplification. Under the optimal conditions, highly sensitive and selective detection of exosomes was achieved ranging from 5.5 × 103 to 1.1 × 107 particles/μL with a limit of detection of 1.29 × 103 particles/μL. Moreover, this method allows the isolation and quantitative analysis of exosomes in several biological fluids with satisfactory recovery rates (92.25-106.8%). Thus, this approach provides a sensitive, anti-interference platform for isolating and detecting exosomes.

Ratiometric signal detection has been widely used in bioelectrochemical sensors because of the good stability and selectivity. A novel biosensor is reported for nucleic acid detection based on the ratio of the oxidation peak current ratio between ferrocene (Fc) and methylene blue (MB) (IFc/IMB) using a proximity-dependent surface hybridization strategy. The design of hairpin capture was shown to reduce the possibility of the hybridization with the detection probe in the absence of the target which improved the specificity. Moreover, this approach improved the signal stability. Additionally, a linear relationship was observed between the ratio of IFc/IMB and the logarithm of the absolute value of DNA concentration from 1.0 × 10−12 M to 1.0 × 10−16 M. This biosensor possessed high sensitivity with a detection limit as low as 0.64 × 10−16 M. Moreover, good selectivity was obtained for the biosensor by identifying the target of the single-base mismatch. Therefore, this ratiometric electrochemical biosensor has great potential applications for nucleic acid detection and medical clinical diagnosis.

Epstein-Barr Virus (EBV) is a tumor-associated virus naturally transmitted through saliva. This virus is the pathogen of infectious mononucleosis, which is closely related to the occurrence of nasopharyngeal carcinoma (NPC) and childhood lymphoma. Although a majority of EBV infected individuals exhibited good tolerance after primary infection, those who carry a viral load greater than the clinical cutoff value (COV), the upper level in healthy carriers, still suffer a high risk of cancer. Herein, a simple, rapid, and effective method, accelerated strand exchange amplification (ASEA), was developed for EBV detection, which could offer a strategy for non-invasive testing of EBV in saliva samples instead of blood samples as in traditional serology based methods and avoid bleeding during diagnosis. This approach could distinguish the genomic DNA of EBV and other species in saliva, and its limit of detection was as low as 1000 copies per mL, which was lower than the COV of EBV. Moreover, DNA extracted from saliva samples (n = 50) was employed as a template for EBV detection via qPCR and ASEA, the result of which showed that ASEA exhibited comparable sensitivity and specificity for actual sample diagnosis. Additionally, similar to conventional PCR, this method requires only one pair of primers and could be performed using a conventional fluorescence instrument, which makes this method easy to accomplish. Therefore, this rapid and effective method has the potential to provide rapid screening platforms for individuals with a high EBV load.

Nanozymes and natural product-derived herbzymes have been identified in different types of enzymes simulating the natural protein-based enzyme function. How to explore and predict enzyme types of novel nanozymes when synthesized remains elusive. An informed analysis might be useful for the prediction. Here, we applied a protein-evolution analysis method to predict novel types of enzymes with experimental validation. First, reported nanozymes were analyzed by chemical classification and nano-evolution. We found that nanozymes are predominantly classified as protein-based EC1 oxidoreductase. In comparison, we analyzed the evolution of protein-based natural enzymes by a phylogenetic tree and the most conserved enzymes were found to be peroxidase and lyase. Therefore, the natural products of Rhizoma polygonati and Goji herbs were analyzed to explore and test the potent new types of natural nanozymes/herbzymes using the simplicity simulation of natural protein enzyme evolution as they contain these conserved enzyme types. The experimental validation showed that the natural products from the total extract of nanoscale traditional Chinese medicine Huangjing (RP, Rhizoma polygonati) from Mount-Tai (Taishan) exhibit fructose-bisphosphate aldolase of lyase while nanoscale Goji (Lycium chinense) extract exhibits peroxidase activities. Thus, the bioinformatics analysis would provide an additional tool for the virtual discovery of natural product nanozymes.

Helicobacter pylori cagA + genotype is a leading risk factor for gastric cancer development making accurate identification and timely eradication of H. pylori critical to deadly gastric cancer prevention. Traditional clinical diagnostic methods, including conventional in vitro culture, histological examination, and (13/14)C-urea breath test methods, could only identify the presence of H. pylori, but these means are not capable of identification of cagA + strains. Herein, we firstly built a multiplex detection system based on novel accelerated PCR that could realize one-step detection of as low as 20 copies of H. pylori 16S rDNA and cagA genes within 30 min. In addition, this novel system performed strong anti-jamming capacity, and exhibited that it could specifically differentiate H. pylori cagA- and cagA + genotypes co-existence with other 4 kinds of gastrointestinal pathogens. Furthermore, this one-step system showed remarkable performance on rapid H. pylori infection diagnosis and cagA + genotypes identification in clinical gastric mucosa samples. Specifically, it outperformed histological examination in terms of accuracy and was superior to conventional PCR and DNA sequencing in terms of efficiency. This rapid, sensitive, and reliable H. pylori detection and identification system would break the limitation of traditional methods and realize H. pylori infection diagnosis and cagA + genotypes identification.

Mycoplasma pneumoniae is a strong infectious pathogen that may cause severe respiratory infections. Since this pathogen may possess a latent period after infection, which sometimes leads to misdiagnosis by traditional diagnosis methods, the establishment of a rapid and sensitive diagnostic method is crucial for transmission prevention and timely treatment. Herein, a novel detection method was established for M. pneumoniae detection. The method, which improves upon a denaturation bubble-mediated strand exchange amplification (SEA) that we developed in 2016, is called accelerated SEA (ASEA). The established ASEA achieved detection of 1% M. pneumoniae genomic DNA in a DNA mixture from multiple pathogens, and the limit of detection (LOD) of ASEA was as low as 1.0 × 10−17 M (approximately 6.0 × 103 copies/mL). Considering that the threshold of an asymptomatic carriage is normally recommended as 1.0 × 104 copies/mL, this method was able to satisfy the requirement for practical diagnosis of M. pneumoniae. Moreover, the detection process was finished within 20.4 min, significantly shorter than real-time PCR and SEA. Furthermore, ASEA exhibited excellent performance in clinical specimen analysis, with sensitivity and specificity of 96.2% and 100%, respectively, compared with the “gold standard” real-time PCR. More importantly, similar to real-time PCR, ASEA requires only one pair of primers and ordinary commercial polymerase, and can be carried out using a conventional fluorescence real-time PCR instrument, which makes this method low-cost and easy to accomplish. Therefore, ASEA has the potential for wide use in the rapid detection of M. pneumoniae or other pathogens in large numbers of specimens. Graphical abstract

Real-time fluorescence detection of nucleic acid exhibit excellent performance in analytical and diagnostic applications. However, the requirement of laboratory-based instrument and complex nucleic acid extraction greatly limits their application in point-of-care testing (POCT). Herein, a novel integrated silica membrane–based platform incorporating nucleic acid purification, amplification, and detection steps was developed. A universal and portable visualization platform was fabricated by incorporating denaturation bubble-mediated strand exchange amplification (SEA) reaction with silica membrane. The fluorescence signal of SYBR Green I with amplification products was visualized by the naked eye using a simple ultraviolet light on the silica membrane, and significant discrimination between the positive and negative samples could be easily and visually obtained. Besides, chitooligosaccharide-modified silica membrane allows the purification of nucleic acid in a totally aqueous system and enables in situ SEA. With the proposed integrated platform, 102–108 cfu/mL Vibrio parahaemolyticus could be successfully detected and excellent performance was also revealed for gram-positive pathogens. The detection limit of the method for artificially spiked oysters was 103 cfu/g and reached 100 cfu/g after 12 h enrichment. This proof-of-concept method could also be applied to a variety of nucleic acid amplification methods. We believe that the proposed silica membrane–based platform has great potential for the rapid and low-cost detection of nucleic acids especially in low-resource settings.

Due to the increasingly heated debate on the potential threat of genetically modified (GM) crops to human health and environment, regulations and laws relevant to GM crops have been issued in many countries and regions to strictly restrict their cultivation and application. Therefore, fast and accurate method to realized on-site detection of GM crops is greatly demanded. In this work, a novel isothermal amplification method termed denaturation bubble-mediated strand exchange amplification (SEA) was proposed first time to detect GM crops. Fluorescence assay based on SEA could accurately distinguished GM and non-GM soybean by detecting agrobacterium tumefaciens nopaline synthase (NOS) terminator, which was widely incorporated in GM crops. Moreover, this feasible and specific method could detect NOS terminator from as low as 200 pg/μL total genomic DNA of GM soybean. In addition, in the actual sample detection, the result of colorimetric assay based on SEA results could be directly observed by the naked eyes within 58 min. Compared with the traditional methods based on PCR, which normally required complex equipment, skilled technicians and long operation time, this simple, fast and precise method is more desirable for the on-site GM crops detection.

We examined the relationship between entrepreneurs' social networks and opportunity identification, and the moderating roles of entrepreneurial passion and entrepreneurial alertness in this relationship. Results from 142 entrepreneurs supported the hypothesis that both their business ties and their political ties would be positively related to opportunity identification, and these relationships would be moderated by entrepreneurial passion and entrepreneurial alertness. Entrepreneurial passion weakened the relationship between business ties and opportunity identification, but amplified the relationship between political ties and opportunity identification. Further, entrepreneurial alertness strengthened the relationship between business ties and opportunity identification. The results suggest that the effect of entrepreneurs' social ties on opportunity identification depends on the level of the individual's entrepreneurial passion and entrepreneurial alertness.

We reported a novel detection method named accelerated strand exchange amplification by employing Bst DNA polymerase and narrow-thermal-cycling for the first time, achieving direct detection of 120 copies of DNA within 15 min and 1.2 × 105 copies of RNA within 20 min and sparking the revolution of the use of routine isothermal polymerases for diverse applications.

The DNA tetrahedron has developed a broad spectrum of applications in biosensor construction thanks to its excellent mechanical rigidity and structural stability. However, how to construct a highly sensitive biosensor using a DNA tetrahedron is still a challenge. In this work, an ultrasensitive electrochemical biosensor based on a DNA tetrahedral nanostructure was developed with the help of synergy from proximity-dependent hybridization. To decrease the steric hindrance of DNA tetrahedra to proximity-dependent hybridization, the detection signal was set on the inclined side chain structure of a DNA tetrahedral sensing system. Additionally, when the target hybridized with the DNA probe, the ferrocene (Fc) labeled on the end of the DNA probe was driven close to the surface of the biosensor, providing a sensitive faradaic current. The experimental results exhibited a good linear relationship from 1 fM to 10 pM with a linear correlation coefficient of 0.9977, and a high sensitivity with a detection limit of 0.2 fM. Our DNA biosensor also showed good stability according to electrode characterization and target detection at different time scales and the anti-jamming capabilities in a complicated biological extraction environment were excellent. The electrochemical sensing system established here has greatly improved the detection sensitivity of a DNA biosensor based on a DNA tetrahedron, which will further promote its practical applications.

Due to the abuse of antibiotics, the prevalence of antibiotic resistant Helicobacter pylori strains continues to increase. Therefore, antibiotic resistance assessment is now essential in addition to general H. pylori diagnosis in medical institutions to fulfill clinicians administering effective antibiotic regimens. However, the conventional antibiotic resistance assessment methods, such as in vitro antibiotic susceptibility test and E-test, are skilled-staff dependent and time-consuming. The aim of this study was to establish an easy-operating TaqMan-MGB probe multiplex real-time PCR system for one-step detection of levofloxacin and clarithromycin resistance mutations with concurrent H. pylori infection diagnosis. Through the optimization of primers, probes and reaction buffers, this proposed system could accurately distinguish the recombinant plasmids with different mutation markers. More importantly, the diagnosis results of this detection system exhibited excellent consistence with the gold standard of gastric biopsy and Sanger sequencing on the detection of H. pylori infection and relevant antibiotic resistant strains, the Kappa values of which all exceeded 0.90. In addition, the results of this detection system could also be applied for the prevalence statistics of antibiotic resistance patterns for patients by age, gender and geographical location. This simple and rapid system should be beneficial for clinicians issuing personalized treatments according to the patient's H. pylori strains and avoid the abuse of antibiotics.

Broadband absorbers generally consist of plasmonic cavities coupled to metallic resonators separated by a dielectric film, and they are vertically stacking configurations. In this work, we propose an ultra-broadband nanowire metamaterial absorber composed of an array of vertically aligned dielectric nanowires with coaxial metallic rings. The absorber shows strong absorption from 0.2 to 7 μm with an average absorption larger than 91% due to the excitation of gap surface plasmon polariton modes in Fabry–Perot-like resonators. Moreover, a refractory dielectric cladding can be added to improve the thermal stability of the absorber, showing a negligible impact on its absorption performance. The proposed absorber may find potential applications in solar energy harvesting, infrared imaging and spectroscopy, and optoelectronic devices.

Thermo-plasmonics, using plasmonic structures as heat sources, has been widely used in biomedical and microfluidic applications. However, a metasurface with single-element unit cells, considered as the sole heat source in a unit cell, functions at a fixed wavelength and has limited control over the thermo-plasmonically induced hydrodynamic effects. Plasmonic metasurfaces with metal disk heterodimer lattices can be viewed to possess two heat sources within a unit cell and are therefore designed to photo-actively control thermal distributions and fluid dynamics at the nanoscale. The locations of heat sources can be switched, and the direction of the convective flow in the central region of the unit cell can be reversed by shifting the wavelength of the excitation source without any change in the excitation direction or physical actuation of the structural elements. The temperature and velocity of a fluid are spatiotemporally controlled by the wavelength selectivity and polarization sensitivity of the plasmonic metasurface. Additionally, we investigate the effects of geometric parameters on the surface lattice resonances and their impact on the temperature and fluid velocity of the optofluidic system. Our results demonstrate excellent optical control of these plasmonic metasurface heating and thermal convection performances to design flexible platforms for microfluidics.