Traceability of Microplastic Fragments from Waste Plastic Express Packages Using Near-Infrared Spectroscopy Combined with Chemometrics.

The pollution from waste plastic express packages (WPEPs), especially microplastic (MP) fragments, caused by the blowout development of the express delivery industry has attracted widespread attention. On account of the variety of additives, strong complexity, and high diversity of plastic express packages (PEPs), the multi-class classification of WPEPs is a typical large-class-number classification (LCNC). The traceability and identification of microplastic fragments from WPEPs is very challenging. An effective chemometric method for large-class-number classification would be very beneficial for the comprehensive treatment of WPEP pollution through the recycling and reuse of waste plastic express packages, including microplastic fragments and plastic debris. Rather than using the traditional one-against-one (OAO) and one-against-all (OAA) dichotomies, an exhaustive and parallel half-against-half (EPHAH) decomposition, which overcomes the defects of the OAO's classifier learning limitations and the OAA's data proportion imbalance, is proposed for feature selection. EPHAH analysis, combined with partial least squares discriminant analysis (PLS-DA) for large-class-number classification, was performed on 750 microplastic fragments of polyethylene WPEPs from 10 major courier companies using near-infrared (NIR) spectroscopy. After the removal of abnormal samples through robust principal component analysis (RPCA), the root mean square error of cross-validation (RMSECV) value for the model was reduced to 0.01, which was 21.5% lower than that including the abnormal samples. The best models of PLS-DA were obtained using SNV combined with SG-17 smoothing and 2D (SNV+SG-17+2D); the latent variables (LVs), the error rates of Monte Carlo cross-validation (ERMCCVs), and the final classification accuracies were 6.35, 0.155, and 88.67% for OAO-PLSDA; 5.37, 0.103, and 87.33% for OAA-PLSDA; and 3.12, 0.054, and 96.00% for EPHAH-PLSDA. The results showed that the EPHAH strategy can completely learn the complex LCNC decision boundaries for 10 classes, effectively break the tie problem, and greatly improve the voting resolution, thereby demonstrating significant superiority to both the OAO and OAA strategies in terms of classification accuracy. Meanwhile, PLS-DA further maximized the covariance and data interpretation abilities between the potential variables and categories of microplastic debris, thereby establishing an ideal performance identification model with a recognition rate of 96.00%.

Establishment of Indirect Competitive Enzyme-linked Immunosorbent Assay (ic-ELISA) for Copper ion (Cu2+) in Raw Meat Products.

Adding an appropriate amount of copper to feed can promote the growth and development of livestock; however, a large amount of heavy metal copper can accumulate in livestock through the enrichment effect, which poses a serious threat to human health. Traditional Cu2+ detection relies heavily on complex and expensive instruments, such as inductively coupled plasma-optical emission spectrometry (ICP-OES) and inductively coupled plasma-mass spectrometry (ICP-MS); thus, convenient and simple rapid detection technologies are urgently needed. In this paper, synthesized copper antigens were used to immunize mice and highly specific anticopper monoclonal antibodies were obtained, which were verified to exhibit high affinity and specificity. Based on the above antibodies, an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) was established for the rapid detection of copper content in pork. The standard inhibition curve of the method was obtained by antigen-antibody working concentration screening, in which the half inhibitory concentration (IC50) was 11.888 ng/mL, the limit of detection (LOD) was 0.841 ng/mL and the correlation coefficient R2 of the curve was 0.998. In the additive recovery experiment, the recovery rate ranged from 90% to 110%, and the coefficient of variation (CV) was less than 10%, indicating that the method achieved high accuracy and precision. Finally, the results of ic-ELISA combined with Bland-Altman analysis showed a high correlation with ICP-MS, and the correlation coefficient (R2) reached 0.990 when the copper concentration was less than 200 ng/mL. Thus, the ic-ELISA method exhibits high reliability.

Simultaneous detection of three nitrofuran antibiotics by the lateral flow immunoassay based on europium nanoparticles in aquatic products.

Nitrofuran (NF) antibiotics have been banned worldwide in aquaculture due to their potential carcinogenicity and mutagenicity. Because of the short half-life of NF antibiotics, an easy and sensitive multiple lateral flow immunoassay (mLFIA) based on europium nanoparticles (EuNPs) has been successfully established to simultaneously and quantitatively detect 3-amino-5-morpholinomethyl-2-oxazolidinone (AMOZ), 3-amino-2-oxazolidinone (AOZ) and sodium nifurstylenate (NFS) in aquatic products. The EuNP-mLFIA assay was accomplished within 10 min. The limits of detection (LODs) for AOZ, AMOZ and NFS were 0.013, 0.019 and 0.023 ng/mL, respectively. The average recoveries of AOZ, AMOZ and NFS were 98.0-104.4%, 96.0-102.6% and 98.0-102.8%, respectively. It showed satisfactory consistency, and the feasibility was validated by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Briefly, this method will become a powerful tool for monitoring multiple NF antibiotics and provide promising applications in the field of food safety and environmental testing.

Advances in Detection Techniques for the H5N1 Avian Influenza Virus.

Avian influenza is caused by avian influenza virus infection; the H5N1 avian influenza virus is a highly pathogenic subtype, affecting poultry and human health. Since the discovery of the highly pathogenic subtype of the H5N1 avian influenza virus, it has caused enormous losses to the poultry farming industry. It was recently found that the H5N1 avian influenza virus tends to spread among mammals. Therefore, early rapid detection methods are highly significant for effectively preventing the spread of H5N1. This paper discusses the detection technologies used in the detection of the H5N1 avian influenza virus, including serological detection technology, immunological detection technology, molecular biology detection technology, genetic detection technology, and biosensors. Comparisons of these detection technologies were analyzed, aiming to provide some recommendations for the detection of the H5N1 avian influenza virus.

Prokaryotic Argonaute Proteins: A New Frontier in Point-of-Care Viral Diagnostics.

The recent pandemic of SARS-CoV-2 has underscored the critical need for rapid and precise viral detection technologies. Point-of-care (POC) technologies, which offer immediate and accurate testing at or near the site of patient care, have become a cornerstone of modern medicine. Prokaryotic Argonaute proteins (pAgo), proficient in recognizing target RNA or DNA with complementary sequences, have emerged as potential game-changers. pAgo present several advantages over the currently popular CRISPR/Cas systems-based POC diagnostics, including the absence of a PAM sequence requirement, the use of shorter nucleic acid molecules as guides, and a smaller protein size. This review provides a comprehensive overview of pAgo protein detection platforms and critically assesses their potential in the field of viral POC diagnostics. The objective is to catalyze further research and innovation in pAgo nucleic acid detection and diagnostics, ultimately facilitating the creation of enhanced diagnostic tools for clinic viral infections in POC settings.

Europium Nanoparticle-Based Lateral Flow Strip Biosensors Combined with Recombinase Polymerase Amplification for Simultaneous Detection of Five Zoonotic Foodborne Pathogens.

The five recognized zoonotic foodborne pathogens, namely, Listeria monocytogenes, Staphylococcus aureus, Streptococcus suis, Salmonella enterica and Escherichia coli O157:H7, pose a major threat to global health and social-economic development. These pathogenic bacteria can cause human and animal diseases through foodborne transmission and environmental contamination. Rapid and sensitive detection for pathogens is particularly important for the effective prevention of zoonotic infections. In this study, rapid and visual europium nanoparticle (EuNP)-based lateral flow strip biosensors (LFSBs) combined with recombinase polymerase amplification (RPA) were developed for the simultaneous quantitative detection of five foodborne pathogenic bacteria. Multiple T lines were designed in a single test strip for increasing the detection throughput. After optimizing the key parameters, the single-tube amplified reaction was completed within 15 min at 37 °C. The fluorescent strip reader recorded the intensity signals from the lateral flow strip and converted the data into a T/C value for quantification measurement. The sensitivity of the quintuple RPA-EuNP-LFSBs reached a level of 101 CFU/mL. It also exhibited good specificity and there was no cross-reaction with 20 non-target pathogens. In artificial contamination experiments, the recovery rate of the quintuple RPA-EuNP-LFSBs was 90.6-101.6%, and the results were consistent with those of the culture method. In summary, the ultrasensitive bacterial LFSBs described in this study have the potential for widespread application in resource-poor areas. The study also provides insights in respect to multiple detection in the field.

Triplex-Loop-Mediated Isothermal Amplification Combined with a Lateral Flow Immunoassay for the Simultaneous Detection of Three Pathogens of Porcine Viral Diarrhea Syndrome in Swine.

Porcine epidemic diarrhea virus (PEDV), porcine bocavirus (PBoV), and porcine rotavirus (PoRV) are associated with porcine viral diarrhea. In this study, triplex loop-mediated isothermal amplification (LAMP) combined with a lateral flow dipstick (LFD) was established for the simultaneous detection of PEDV, PoRV, and PBoV. The PEDV-gp6, PoRV-vp6, and PBoV-vp1 genes were selected to design LAMP primers. The amplification could be carried out at 64 °C using a miniature metal bath within 30 min. The triplex LAMP-LFD assay exhibited no cross-reactions with other porcine pathogens. The limits of detection (LODs) of PEDV, PoRV, and PBoV were 2.40 × 101 copies/µL, 2.89 × 101 copies/µL, and 2.52 × 101 copies/µL, respectively. The consistency between rt-qPCR and the triplex LAMP-LFD was over 99% in field samples testing. In general, the triplex LAMP-LFD assay was suitable for the rapid and simultaneous detection of the three viruses in the field.

Europium Nanoparticles-Based Fluorescence Immunochromatographic Detection of Three Abused Drugs in Hair.

Drug abuse is becoming increasingly dangerous nowadays. Morphine (MOP), methamphetamine (MET) and ketamine (KET) are the most commonly abused drugs. The abuse of these drugs without supervision can cause serious harm to the human body and also endanger public safety. Developing a rapid and accurate method to screen drug suspects and thus control these drugs is essential to public safety. This paper presents a method for the simultaneous quantitative detection of these three drugs in hair by a europium nanoparticles-based fluorescence immunochromatographic assay (EuNPs-FIA). In our study, the test area of the nitrocellulose membrane was composed of three equally spaced detection lines and a quality control line. The test strip realized the quantitative analysis of the samples by detecting the fluorescence brightness of the europium nanoparticles captured on the test line within 15 min. For the triple test strip, the limits of detection of MOP, KET and MET were 0.219, 0.079 and 0.329 ng/mL, respectively. At the same time, it also showed strong specificity. The strip was stable and could be stored at room temperature for up to one year, and the average recovery rate was 85.98-115.92%. In addition, the EuNPs-FIA was validated by high-performance liquid chromatography (HPLC) analysis, and a satisfactory consistency was obtained. Compared to the current immunochromatographic methods used for detecting abused drugs in hair, this method not only increased the number of detection targets, but also ensured sensitivity, improving detection efficiency to a certain extent. The approach can also be used as an alternative to chromatography. It provides a rapid and accurate screening method for the detection of abused drugs in hair and has great application prospects in regard to public safety.

Protected Geographical Indication Discrimination of Zhejiang and Non-Zhejiang Ophiopogonis japonicus by Near-Infrared (NIR) Spectroscopy Combined with Chemometrics: The Influence of Different Stoichiometric and Spectrogram Pretreatment Methods.

This paper presents a method for the protected geographical indication discrimination of Ophiopogon japonicus from Zhejiang and elsewhere using near-infrared (NIR) spectroscopy combined with chemometrics. A total of 3657 Ophiopogon japonicus samples from five major production areas in China were analyzed by NIR spectroscopy, and divided into 2127 from Zhejiang and 1530 from other areas ('non-Zhejiang'). Principal component analysis (PCA) was selected to screen outliers and eliminate them. Monte Carlo cross validation (MCCV) was introduced to divide the training set and test set according to a ratio of 3:7. The raw spectra were preprocessed by nine single and partial combination methods such as the standard normal variable (SNV) and derivative, and then modeled by partial least squares regression (PLSR), a support vector machine (SVM), and soft independent modeling of class analogies (SIMCA). The effects of different pretreatment and chemometrics methods on the model are discussed. The results showed that the three pattern recognition methods were effective in geographical origin tracing, and selecting the appropriate preprocessing method could improve the traceability accuracy. The accuracy of PLSR after the standard normal variable was better, with R2 reaching 0.9979, while that of the second derivative was the lowest with an R2 of 0.9656. After the SNV pretreatment, the accuracy of the training set and test set of SVM reached the highest values, which were 99.73% and 98.40%, respectively. The accuracy of SIMCA pretreated with SNV and MSC was the highest for the origin traceability of Ophiopogon japonicus, which could reach 100%. The distance between the two classification models of SIMCA-SNV and SIMCA-MSC is greater than 3, indicating that the SIMCA model has good performance.

Metagenomic next-generation sequencing for pleural effusions induced by viral pleurisy: A case report.

BACKGROUND: Viral pleurisy is a viral infected disease with exudative pleural effusions. It is one of the causes for pleural effusions. Because of the difficult etiology diagnosis, clinically pleural effusions tend to be misdiagnosed as tuberculous pleurisy or idiopathic pleural effusion. Here, we report a case of pleural effusion secondary to viral pleurisy which is driven by infection with epstein-barr virus. Viral infection was identified by metagenomic next-generation sequencing (mNGS). CASE SUMMARY: A 40-year-old male with a history of dermatomyositis, rheumatoid arthritis, and secondary interstitial pneumonia was administered with long-term oral prednisone. He presented with fever and chest pain after exposure to cold, accompanied by generalized sore and weakness, night sweat, occasional cough, and few sputums. The computed tomography scan showed bilateral pleural effusions and atelectasis of the partial right lower lobe was revealed. The pleural fluids were found to be yellow and slightly turbid after pleural catheterization. Thoracoscopy showed fibrous adhesion and auto-pleurodesis. Combining the results in pleural fluid analysis and mNGS, the patient was diagnosed as viral pleuritis. After receiving Aciclovir, the symptoms and signs of the patient were relieved. CONCLUSION: Viral infection should be considered in cases of idiopathic pleural effusion unexplained by routine examination. mNGS is helpful for diagnosis.

Attenuating endothelial leakiness with self-assembled DNA nanostructures for pulmonary arterial hypertension.

Vascular endothelium dysfunction plays an important role in oncological and pulmonary diseases. Endothelial barrier dysfunction is the initial step of pulmonary vascular remodeling (PVR) and pulmonary arterial hypertension. Upregulation of a pro-autophagy protein Atg101 in the endothelial cells triggered a cascade of intracellular events that leads to endothelial dysfunction through apoptosis. Herein, we proposed a strategy that used endothelial targeting DNA nanostructures to deliver Atg101 siRNA (siAtg101) as a safe, biocompatible "band-aid" to restore pulmonary arterial endothelial barrier integrity within the intricate milieu of pulmonary cells and the pulmonary vasculature. The siAtg101 and aptamer conjugated DNA nanostructures were found to attenuate hypoxia-induced pulmonary endothelial leakiness with surprisingly high selectivity and efficacy. Further in vivo study revealed that functionalized DNA nanostructures likewise attenuated the vascular remodeling in a monocrotaline-induced PVR mouse model. Mechanistically, functionalized DNA nanostructures suppressed PVR by knocking down Atg101, which in turn, downregulated Beclin-1 and subsequently upregulated VE-cadherin to restore endothelial cells' adherin junctions. This work opened a new window for future nanomaterial design that directly addresses the interfacial endothelial cell layer that often stands between the blood and many diseased sites of nanotherapeutic interest.

The Double-Deck Viscoelastic Technique: a Novel Surgical Technique to Protect the Corneal Endothelium in Penetrating Keratoplasty of Aphakic Silicone Oil-Dependent Eyes after Severe Ocular Injury.

INTRODUCTION: The purpose of this study is to summarize the benefits of the double-deck viscoelastic technique (DDVT), a novel and cost-effective surgical technique that creates a barrier to hinder silicone oil (SO) from connecting and damaging the corneal endothelium in aphakic and SO-dependent eyes. METHODS: Five SO-dependent and aphakic eyes underwent double-deck viscoelastic embedment and penetrating keratoplasty (PKP) in this retrospective case series. At 1, 6, 12, 18, and 24 months after surgery, clinical outcomes including best corrected visual acuity (BCVA), intraocular pressure (IOP), corneal endothelial cell density (ECD), and double-deck viscoelastic layer imaging were evaluated. A Heidelberg Retina Tomograph confocal microscope was used to measure ECD. Ultrasound biomicroscopy (UBM) was used to image the double-deck viscoelastic layer. RESULTS: Postoperatively, the BCVA of the patients ranged from hand motion detection to 20/200, and their IOP was between 7 and 10 mmHg. The two-deck viscoelastic layer remained mostly static. Patients showed varying degrees of ECD reduction, with ECD loss rates in the first 6 months ranging from 6.7 to 75.8 cells/mm2/month and then declining to 2.2-14.3 cells/mm2/month. CONCLUSION: In SO-dependent aphakic eyes, double-deck viscoelastic embedment could effectively inhibit SO-corneal endothelium interaction. This technique could lower the pace of ECD loss and lengthen the time of corneal transparency, giving aphakic and silicone oil-dependent patients the opportunity to accept PKP surgery and get better vision quality.

Antibodies Induced by Homologous or Heterologous Inactivated (CoronaVac/BBIBP-CorV) and Recombinant Protein Subunit Vaccines (ZF2001) Dramatically Enhanced Inhibitory Abilities against B.1.351, B.1.617.2, and B.1.1.529 Variants.

Safe and effective vaccines for Corona Virus Disease 2019 (COVID-19) can prevent the virus from infecting human populations and treat patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this study, we discuss the inhibitory abilities of primary and booster vaccine-induced antibodies inhibitory ability toward the SARS-CoV-2 wild-type strain, as well as B.1.1.7, B.1.351, P.1, B.1.617.2, and B.1.1.529. We confirmed these antibodies had the strongest inhibitory effects on the wild-type strain and cross-inhibition activities against other mutant strains after two inactivated vaccine doses. However, the B.1.351, B.1.617.2 and B.1.1.529 mutants exhibit antibody resistance in the vaccine serum. Antibodies induced by homologous inactivated vaccines (n = 92) presented more effective inhibition against tested SARS-CoV-2 strains (p < 0.0001), especially B.1.351, B.1.617.2, and B.1.1.529 mutant strains, which had strong immune escape characteristics. In addition, a heterologous booster vaccination (n = 50) of a protein subunit vaccine ZifiVax (ZF2001) significantly restored humoral immune responses and even showed an increasing response against wild-type, B.1.351, B.1.617.2, and B.1.1.529 than homologous inactivated vaccines. Our analysis of the humoral immune response elicited by the different vaccine regimens, including inhibiting antibodies, indicated that a booster, whether homologous or heterologous, could be essential for achieving greater efficacy against SARS-CoV-2.

Quantum-Dot-Bead-Based Fluorescence-Linked Immunosorbent Assay for Sensitive Detection of Cry2A Toxin in Cereals Using Nanobodies.

In this study, a quantum-dot-bead (QB)-based fluorescence-linked immunosorbent assay (FLISA) using nanobodies was established for sensitive determination of the Cry2A toxin in cereal. QBs were used as the fluorescent probe and conjugated with a Cry2A polyclonal antibody. An anti-Cry2A nanobody P2 was expressed and used as the capture antibody. The results revealed that the low detection limit of the developed QB-FLISA was 0.41 ng/mL, which had a 19-times higher sensitivity than the traditional colorimetric ELISA. The proposed assay exhibited a high specificity for the Cry2A toxin, and it had no evident cross-reactions with other Cry toxins. The recoveries of Cry2A from the spiked cereal sample ranged from 86.6-117.3%, with a coefficient of variation lower than 9%. Moreover, sample analysis results of the QB-FLISA and commercial ELISA kit correlated well with each other. These results indicated that the developed QB-FLISA provides a potential approach for the sensitive determination of the Cry2A toxin in cereals.

The Efficacy and Safety of New-Generation Intense Pulsed Light in the Treatment of Meibomian Gland Dysfunction-Related Dry Eye: A Multicenter, Randomized, Patients-Blind, Parallel-Control, Non-Inferiority Clinical Trial.

INTRODUCTION: This study aimed to evaluate the efficacy and safety of a new-generation intense pulsed light (IPL) device in improving the symptoms and signs of meibomian gland dysfunction (MGD)-related dry eye, and compare it with a traditional IPL device. METHODS: This multicenter randomized controlled trial enrolled 132 patients with MGD-related dry eye from two centers. Patients were randomly assigned into the new-generation IPL (Eyesis) group or traditional IPL (E-Eye) group, and then blinded to receive treatment on days 0 and 7. Ocular Surface Disease Index (OSDI), tear meniscus height (TMH), tear breakup time (TBUT), corneal fluorescein staining (CFS), Schirmer test, and meibomian gland signs were evaluated on days 0, 7, and 14. The primary outcome was defined as the effective rate of treating MGD at day 14. Any adverse events were recorded for safety assessment. Intergroup comparisons and non-inferiority analysis were performed. p values less than 0.05 were considered statistically significant. RESULTS: Basic information showed no significant difference between treatment groups. The intergroup difference of the effective rate was - 1.7% in the left eye and 1.6% in right eye, verifying the non-inferiority of the Eyesis device (p = 0.927). Significant improvements in OSDI, TBUT, Schirmer test, TMH, CFS, and meibomian gland signs were observed in Eyesis group on days 7 and 14 (all p < 0.05). Compared to the E-Eye group, the Eyesis group achieved more significant improvements in OSDI, TBUT, Schirmer test, TMH, and meibum quality (all p < 0.05). There was no significant difference in the incidences of adverse events between groups (p = 1.000). CONCLUSIONS: The new-generation IPL was effective and safe in relieving the symptoms and signs of MGD-related dry eye, exhibiting a non-inferior effective rate compared to the traditional IPL. Additionally, Eyesis showed more clinical benefits over E-Eye in alleviating symptoms, increasing tear film stability and improving meibomian gland function.

Impact of Air Pollution on the Ocular Surface and Tear Cytokine Levels: A Multicenter Prospective Cohort Study.

Purpose: To assess air pollution-induced changes on ocular surface and tear cytokine levels. Methods: As a prospective multicenter cohort study, 387 dry eye disease (DED) participants were recruited from five provinces in China and underwent measurements of ocular surface disease index (OSDI), Schirmer's I test (ST), tear meniscus height (TMH), tear film break-up time (TBUT), corneal fluorescein staining (CFS), meibomian gland (MG) function, and tear cytokines. The associations between ocular surface parameters and exposure to particulate matter (PM), ozone (O3), nitrogen dioxide (NO2), and sulfur dioxide (SO2) for 1 day, 1 week, and 1 month before the examination were analyzed in single- and multi-pollutant models adjusted for confounding factors. Results: In the multi-pollutant model, the OSDI score was positively correlated with PM with diameter ≤2.5 µm (PM2.5), O3, and SO2 exposure [PM2.5: ß (1 week/month) = 0.229 (95% confidence interval (CI): 0.035-0.424)/0.211 (95% CI: 0.160-0.583); O3: ß (1 day/week/month) = 0.403 (95% CI: 0.229-0.523)/0.471 (95% CI: 0.252-0.693)/0.468 (95% CI: 0.215-0.732); SO2: ß (1 day/week) = 0.437 (95% CI: 0.193-0.680)/0.470 (95% CI: 0.040-0.901)]. Tear secretion was negatively correlated with O3 and NO2 exposures but positively correlated with PM2.5 levels. Air pollutants were negatively correlated with TBUT and positively related with CFS score. Besides SO2, all other pollutants were associated with aggravated MG dysfunction (MG expression, secretion, and loss) and tear cytokines increasement, such as PM2.5 and interleukin-8 (IL-8) [ß (1 day) = 0.016 (95% CI: 0.003-0.029)], PM with diameter ≤10 µm (PM10) and IL-6 [ß (1 day) = 0.019 (95% CI: 0.006-0.033)], NO2 and IL-6 [ß (1 month) = 0.045 (95% CI: 0.018-0.072)], among others. The effects of air pollutants on DED symptoms/signs, MG functions and tear cytokines peaked within 1 week, 1 month, and 1 day, respectively. Conclusion: Increased PM2.5, O3, and SO2 exposures caused ocular discomfort and damage with tear film instability. PM10 exposure led to tear film instability and ocular injury. PM, O3, and NO2 exposures aggravated MG dysfunction and upregulated tear cytokine levels. Therefore, each air pollutant may influence DED via different mechanisms within different time windows.

Simultaneous Detection of Five Foodborne Pathogens Using a Mini Automatic Nucleic Acid Extractor Combined with Recombinase Polymerase Amplification and Lateral Flow Immunoassay.

In recent years, foodborne disease outbreaks have caused huge losses to the economy and have had severe impacts on public health. The accuracy and variety of detection techniques is crucial to controlling the outbreak and spread of foodborne diseases. The need for instruments increases the difficulty of field detection, while manually-handled samples are subject to user error and subjective interpretation. Here, we use a mini automatic nucleic acid extractor combined with recombinant polymerase amplification (RPA) and lateral flow immunoassay (LFIA) for simultaneous quantitative detection of five major foodborne pathogens. The pre-treatment device using the magnetic bead method allows for nucleic acid extraction of the reagent tank without manual operation, which is highly efficient and stable for preventing aerosol contamination. The nuc gene of Staphylococcus aureus, the toxR gene of Vibrio parahaemolyticus, the rfbE gene of Escherichia coli O157:H7, the hlyA gene of Listeria monocytogenes, and the fimY gene of Salmonella enterica were used as target fragments. The labeled antibody concentration is optimized on the LFIA to find the equilibrium point for the binding capacity of the five chemical markers and to efficiently and accurately visualize the bands. The RPA assay shows an optimal performance at 37 °C for 15 min. The optimized RPA-LFIA detection limit can reach 101 CFU/mL. There was no cross-reactivity among forty-eight strains. Furthermore, the average recoveries in spiked food samples were 90.5-104.5%. In summary, the RPA-LFIA established in this study can detect five pathogenic bacteria simultaneously with little dependence on laboratory equipment, and it has promising prospects for screening in low-resource areas.

Low-Cost Detection of Methane Gas in Rice Cultivation by Gas Chromatography-Flame Ionization Detector Based on Manual Injection and Split Pattern.

Rice cultivation is one of the most significant human-created sources of methane gas. How to accurately measure the methane concentration produced by rice cultivation has become a major problem. The price of the automatic gas sampler used as a national standard for methane detection (HJ 38-2017) is higher than that of gas chromatography, which greatly increases the difficulty of methane detection in the laboratory. This study established a novel methane detection method based on manual injection and split pattern by changing the parameters of the national standard method without adding any additional automatic gas samplers. The standard curve and correlation coefficient obtained from the parallel determination of methane standard gas were y = 2.4192x + 0.1294 and 0.9998, respectively. Relative standard deviation (RSD, <2.82%), recycle rate (99.67−102.02%), limit of detection (LOD, 0.0567 ppm) and limit of quantification (LOQ, 0.189 ppm) of this manual injection method are satisfying, demonstrating that a gas chromatography-flame ionization detector (GC-FID), based on manual injection at a split ratio (SR) of 5:1, could be an effective and accurate method for methane detection. Methane gases produced by three kinds of low-methane rice treated with oxantel pamoate acid, fumaric acid and alcohol, were also collected and detected using the proposed manual injection approach Good peak shapes were obtained, indicating that this approach could also be used for quantification of methane concentration.

Research on Rapid Detection Technology for ß2-Agonists: Multi-Residue Fluorescence Immunochromatography Based on Dimeric Artificial Antigen.

To detect two types of ß2-agonist residues at the same time, we coupled two haptens of clenbuterol (CLE) and ractopamine (RAC) to the same carrier protein through diazotization to prepare dimeric artificial antigen, and a fluorescent lateral flow immunoassay method based on europium nanoparticles (EuNP-FLFIA) was established by combining polyclonal antibodies with europium nanoparticles to form probes. Under optimized conditions, the EuNP-FLFIA could simultaneously detect eight aniline-type and one phenol-type ß2-agonists, and the limits of detection (LOD) were 0.11−0.19 ng/mL and 0.12 ng/mL, respectively. The recovery rate of this method was 84.00−114.00%. This method was verified by liquid chromatography−tandem mass spectrometry (LC-MS/MS), and the test results were consistent (R2 > 0.98). Therefore, the method established in this study could be used as a high-throughput screening for the efficient and sensitive detection of ß2-agonists in food.

[Development of a colloidal gold based immunochromatographic strip for 8-OHdG detection].

8-hydroxy-2'-deoxyguanosine (8-OHdG) is a sensitive and stable biomarker for evaluating DNA oxidative damage. A rapid and sensitive colloidal gold immunochromatographic strip was developed for 8-OHdG detection by a competitive method. The sample pad (glass cellulose film), bonding pad (glass cellulose film), nitrocellulose film and absorbent pad were pasted on the polyvinyl chloride (PVC) base plate to construct the test strip. Colloidal gold (AuNPs) was prepared by the reduction of chloroauric acid with sodium citrate. 8-OHdG antibody (Ab) was coated on the outer layer of AuNPs to form Ab@AuNPs as a probe. Bovine serum albumin (BSA) and 8-OHdG were conjugated with carbodiimide hydrochloride to prepare an artificial antigen, which was used as the coating antigen of detection line. Goat anti mouse polyclonal antibody IgG was used as the coating antibody of control line. The experimental parameters were optimized including the type of nitrocellulose membrane, the formula of loading solution, and the spraying amount of gold labeled antibody. The results showed that the appropriate nitrocellulose membrane was CN 95. The optimal loading solution included BSA (1%), Tween-20 (3%), sucrose (3%) and NaCl (0.9%). The optimal spraying amount of gold labeled antibody was 4 µL. 8-OHdG can be detected by the strip under visible light, and the level of 8-OHdG in urine can be preliminarily determined by comparing the color intensity of T line and C line. The 8-OHdG concentration in urine was further calculated by the gray value of T line and the threshold of detection was 2.55 µg/L. This colloidal gold immunochromatographic strip is simple, rapid and specific for detecting 8-OHdG in human urine to preliminarily evaluate the human status.