Approach For Rapid Detection Research Articles

Meat Vulnerabilities to Economic Food Adulteration Require New Analytical Solutions.

Meat has been identified as one of the food categories at most risk of food fraud. Meat species substitution has been in the spotlight with the European horse meat scandal in 2013. Analysis of cases reported on the web shows that incidents of meat substitution are still recurring worldwide. Altogether these cases highlight significant weaknesses in the supply chain transparency and traceability of raw meat materials. This has triggered recent progress from the food industry to apply new software tools enabling the mapping of meat supply chains. Nevertheless, a meat vulnerability assessment showed that meat and derivatives are highly susceptible to many fraudulent malpractices. Therefore, more effective measures are needed to manage the risk and new analytical solutions are required to increase the deterrence of meat adulteration and rapid detection of fraud. DNA-based methods have evolved rapidly as shown with the application of the new LCD array and Next Generation Sequencing (NGS) in order to detect broad meat species adulteration. Moreover, new technologies such as NGS together with the Rapid Evaporative Ionization Mass Spectrometry (REIMS) are emerging as a really promising association of analytical approaches for rapid detection of several malpractices.

Rapid detection and characterization of postpasteurization contaminants in pasteurized fluid milk

Microbial spoilage of pasteurized fluid milk is typically due to either (1) postpasteurization contamination (PPC) with psychrotolerant gram-negative bacteria (predominantly Pseudomonas) or (2) growth of psychrotolerant sporeformers (e.g., Paenibacillus) that have the ability to survive pasteurization when present as spores in raw milk, and to subsequently grow at refrigeration temperatures. While fluid milk quality has improved over the last several decades, continued reduction of PPC is hampered by the lack of rapid, sensitive, and specific methods that allow for detection of PPC in fluid milk, with fluid milk processors still often using time-consuming methods (e.g., Moseley keeping quality test). The goal of this project was to utilize a set of commercial fluid milk samples that are characterized by a mixture of samples with PPC due to psychrotolerant gram-negative bacteria and samples with presence and growth of psychrotolerant sporeforming bacteria to evaluate different approaches for rapid detection of PPC. Comprehensive microbiological shelf-life characterization of 105 pasteurized fluid milk samples obtained from 20 dairy processing plants showed that 60/105 samples reached bacterial counts >20,000 cfu/mL over the shelf-life due to PPC with gram-negative bacteria. Among these 60 samples with evidence of gram-negative PPC spoilage over the shelf-life, 100% (60/60) showed evidence of contamination with noncoliform, non-Enterobacteriaceae (EB) gram-negative bacteria (e.g., Pseudomonas), 20% (12/60) showed evidence of contamination with coliforms, and 7% (4/60) showed evidence of contamination with noncoliform EB. Among the remaining 45 samples, 28 showed levels of gram-positive bacteria above 20,000 cfu/mL and the remaining 17 samples did not exceed 20,000 cfu/mL over the shelf-life. Evaluation of the same set of 105 samples using 6 different approaches {all possible combinations of 2 different enrichment protocols (13°C or 21°C for 18 h) and 3 different plating media [crystal violet tetrazolium agar, EB Petrifilm (3M, St. Paul, MN), and Coliform Petrifilm]} showed that enrichment at 21°C for 18 h, followed by plating on crystal violet tetrazolium agar provided for the most sensitive, accelerated detection of samples that reached >20,000 cfu/mL due to PPC with psychrotolerant gram-negatives (70% sensitivity). These results show that tests still required and traditionally used in the dairy industry (e.g., coliform testing) are not suitable for monitoring for PPC. Rather, approaches that allow for detection of all gram-negative bacteria are essential for improved detection of PPC in fluid milk.

A novel high-resolution melting analysis approach for rapid detection of vancomycin-resistant enterococci.

BACKGROUNDVancomycin-resistant enterococci (VRE) are resistant to most classes of antibiotics. Diagnosis of VRE using standard methods takes 2 to 5 days. Development of a rapid PCR-assay that detects and identifies resistant genes in bacteria would provide time-critical information on the presence of VRE in clinical samples allowing early treatment and management of infected patients.OBJECTIVESInvestigate the use of high resolution melting analysis (HRMA) and 16S-rRNA-PCR approach for rapid and cost-effective identification of VRE.DESIGNDescriptive antibiotic susceptibility studies.SETTINGManchester Academic Health Sciences Centre and School of Translational Medicine, University of Manchester, UK, and Department of Clinical Laboratory Sciences, Taibah University, Saudi Arabia.MATERIALS AND METHODSPCR-HRMA using 16S-rRNA V1-primers was used to detect and identify VRE. DNA from different strains of vancomycin-resistant and -sensitive Enterococcus faecalis (VSE) and Enterococcus faecium were amplified using V1-primer followed by HRMA in a single run. Differentiation of VRE from VSE was based on curve shapes generated against reference organisms (Bacteroides fragilis).MAIN OUTCOMES MEASURESAmplification curves and difference plots for VRE and VSE.RESULTSDifference plots were generated for all vancomycin-resistant and -sensitive E faecalis and E faecium strains by subtracting their fluorescence melting profile from that of a reference-species B fragilis. A characteristic curve shape was produced by vancomycin-sensitive E faecalis and E faecium. However, vancomycin-resistant strains of these bacteria were associated with a markedly different curve shape facilitating a clear differentiation.CONCLUSIONThe 16S-PCR-HRMA approach has the potential for detecting vancomycin-resistant E faecium and E faecalis. Data with VRE provide the basis for combining VRE identification with pathogens speciation in a rapid, cheap assay able to identify a pathogen as an Enterococcus and whether it is vancomycin-sensitive or -resistant E faecium or E faecalis in a single PCR and HRMA run.LIMITATIONSTested on specific, but not all, reference Enterococcus species and clinical isolates.

Nanoparticle-Enhanced Plasmonic Biosensor for Digital Biomarker Detection in a Microarray.

Nanoplasmonic devices have become a paradigm for biomolecular detection enabled by enhanced light-matter interactions in the fields from biological and pharmaceutical research to medical diagnostics and global health. In this work, we present a bright-field imaging plasmonic biosensor that allows visualization of single subwavelength gold nanoparticles (NPs) on large-area gold nanohole arrays (Au-NHAs). The sensor generates image heatmaps that reveal the locations of single NPs as high-contrast spikes, enabling the detection of individual NP-labeled molecules. We implemented the proposed method in a sandwich immunoassay for the detection of biotinylated bovine serum albumin (bBSA) and human C-reactive protein (CRP), a clinical biomarker of acute inflammatory diseases. Our method can detect 10 pg/mL of bBSA and 27 pg/mL CRP in 2 h, which is at least 4 orders of magnitude lower than the clinically relevant concentrations. Our sensitive and rapid detection approach paired with the robust large-area plasmonic sensor chips, which are fabricated using scalable and low-cost manufacturing, provides a powerful platform for multiplexed biomarker detection in various settings.

Closed tube loop-mediated isothermal amplification assay for rapid detection of hepatitis B virus in human blood

Recently, many studies have demonstrated the significant advantages of loop-mediated isothermal amplification (LAMP) based methods over serological tests and PCR for rapid detection of microbial pathogens. Here, a rapid LAMP assay was developed to detect the hepatitis B virus (HBV) from DNA, and particularly, blood samples from infected patients using a commercially available master mix and portable real-time fluorometer. The final optimized fluorescence-based LAMP assay provided significant amplification time of less than 15 minutes compared with over 1 hour for PCR and an opened tube LAMP system described previously. Results indicated that fluorescence-based LAMP assay was more sensitive than PCR as a rapid, sensitive, efficient, and highly reliable approach for rapid detection of HBV.

Highly specific and sensitive determination of propyl gallate in food by a novel fluorescence sensor

Propyl gallate (PG), one of the most widely used synthetic phenolic antioxidants in edible oil, cookies and fried food, has received extensive concern due to its possible toxic effects on human health. Herein, a novel fluorescence analytical method is firstly proposed to sensitively and selectively determine propyl gallate (PG) by utilizing the unique fluorescence quenching property of organic molybdate complex (OMC) formed by the specific reaction between MoO42− and PG to g-C3N4 nanosheets. Under the optimum conditions, the developed fluorescence sensor allows highly sensitive detection of PG in a wide range from 0.5 to 200 μg mL−1 with a detection limit of 0.11 μg mL−1, and possesses excellent specificity and good recoveries. All the analytical results indicate the present method provides an effective approach for rapid detection of PG in common products, which is beneficial for monitoring and reducing the risk of overuse of PG.

A simple approach for rapid detection and quantification of adulterants in stingless bees (Heterotrigona itama) honey

In this study, we propose an easy approach by combining the Fourier transform infrared and attenuated total reflectance (FTIR-ATR) spectroscopy together with chemometrics analysis for rapid detection and accurate quantification of five adulterants such as fructose, glucose, sucrose, corn syrup and cane sugar in stingless bees (Heterotrigona itama) honey harvested in Malaysia. Adulterants were classified using principal component analysis and soft independent modeling class analogy, where the first derivative of the spectra in the wavenumber range of 1180–750cm−1 was utilized. The protocol could satisfactorily discriminate the stingless bees honey samples that were adulterated with the concentrations of corn syrup above 8% (w/w) and cane sugar over 2% (w/w). Feasibility of integrating FTIR-ATR with chemometrics for precise quantification of the five adulterants was affirmed using partial least square regression (PLSR) analysis. The study found that optimal PLSR analysis achieved standard error of calibrations and standard error of predictions within an acceptable range of 0.686–1.087% and 0.581–1.489%, respectively, indicating good predictive capability. Hence, the method developed here for detecting and quantifying adulteration in H. itama honey samples is accurate and rapid, requiring only 7–8min to complete as compared to 3h for the standard method, AOAC method 998.12.

A “drop‐wipe‐test” SERS method for rapid detection of pesticide residues in fruits

AbstractA simple “drop‐wipe‐test” approach for rapid detection of pesticide residues in fruits was developed based on surface‐enhanced Raman spectroscopy (SERS) coupled with wiper‐type filter paper substrate. The filter paper was coated with silver nanoparticles (Ag NPs) and used as a flexible and absorbent wiper‐type SERS substrate. The first two steps “drop” and “wipe” were combined to simplify the procedures of extraction and sampling of the analyte molecules. “Test” was the last step to obtain the spectral data using a portable Raman spectrometer (Hx‐Spec) developed by our laboratory. The entire detection process was completed just in a few minutes. The optimal wipe time of ~15 s was confirmed used to ensure a thorough extraction of analyte molecules. The as‐prepared SERS substrate was used for rapid detection of pesticide residue (i.e., thiram) in apple, pear, and grape by “drop‐wipe‐test” method. Results demonstrate that the concentrations of thiram spiked on the three fruits skin show a linearly relationship with the average intensity (n = 7) of SERS spectra with R‐square values of 0.9991, 0.9872, and 0.9841, respectively. The limit of detection of thiram in apple, pear, and grape peel was 4.6261, 5.1799, and 5.7061 ng/cm2, respectively. The detection limits are all below the maximum residue limits for pesticide in food that were set by the National Food Safety Standard of China (GB). The results demonstrate that SERS method coupled with a flexible and absorbent SERS substrate can be used as a practical application for a reliable, rapid, and sensitive detection of pesticide residues.

Highly sensitive detection of triazophos pesticide using a novel bio-bar-code amplification competitive immunoassay in a micro well plate-based platform

This study reports a novel bio-bar-code amplification competitive immunoassay for the detection of pesticide residue combined with a micro well plate. The sensing competitive immunoassay was made up of two types of particles: (1) the gold nanoparticles (AuNPs) with recognition elements (monoclonal antibody: McAb) and hundreds of thiolated single-strand oligonucleotide bar-codes; and (2) the magnetic microparticle (MMPs) with competition elements (hapten-OVA) for the target pesticide. Target pesticide and pesticide hapten competed with McAb labeled on the surface of AuNPs. The bar-code strands were released by dithiothreitol. Then a simple method based on micro well plate was used for the quantification of the bar-code strands. The bar-code strands with the half-complementary biotinylated DNA and half-complementary DNA-modified gold nanoparticles probe were immobilized onto the surface of a streptavidin-coated micro well plate, and the signal was amplified by silver enhancement. Triazophos (TAP), as a pesticide model, was detected by the proposed immunoassay. The linear range was from 2.5×10−2 to 40.0ngmL−1, and LOD of the immunoassay was 1.96×10−2ngmL−1. The correlation was further studied between this method and GC–MS analysis. Therefore, this method provided a promising approach for rapid detection and screening of pesticide residue.

High-throughput screening of rare metabolically active tumor cells in pleural effusion and peripheral blood of lung cancer patients

Malignant pleural effusion (MPE), the presence of malignant cells in pleural fluid, is often the first sign of many cancers and occurs in patients with metastatic malignancies. Accurate detection of tumor cells in pleural fluid is crucial because the presence of MPE denotes an advanced stage of disease and directs a switch in clinical managements. Cytology, as a traditional diagnostic tool, has limited sensitivity especially when tumor cells are not abundant, and may be confounded by reactive mesothelial cells in the pleural fluid. We describe a highly sensitive approach for rapid detection of metabolically active tumor cells in MPE via exploiting the altered glucose metabolism of tumor cells relative to benign cells. Metabolically active tumor cells with high glucose uptake, as evaluated by a fluorescent glucose analog (2-NBDG), are identified by high-throughput fluorescence screening within a chip containing 200,000 addressable microwells and collected for malignancy confirmation via single-cell sequencing. We demonstrate the utility of this approach through analyzing MPE from a cohort of lung cancer patients. Most candidate tumor cells identified are confirmed to harbor the same driver oncogenes as their primary lesions. In some patients, emergence of secondary mutations that mediate acquired resistance to ongoing targeted therapies is also detected before resistance is manifested in the clinical imaging. The detection scheme can be extended to analyze peripheral blood samples. Our approach may serve as a valuable complement to cytology in MPE diagnosis, helping identify the driver oncogenes and resistance-leading mutations for targeted therapies.

Towards Cost-Effective Operational Monitoring Systems for Complex Waters: Analyzing Small-Scale Coastal Processes with Optical Transmissometry

The detection and prediction of changes in coastal ecosystems require a better understanding of the complex physical, chemical and biological interactions, which involves that observations should be performed continuously. For this reason, there is an increasing demand for small, simple and cost-effective in situ sensors to analyze complex coastal waters at a broad range of scales. In this context, this study seeks to explore the potential of beam attenuation spectra, c(λ), measured in situ with an advanced-technology optical transmissometer, for assessing temporal and spatial patterns in the complex estuarine waters of Alfacs Bay (NW Mediterranean) as a test site. In particular, the information contained in the spectral beam attenuation coefficient was assessed and linked with different biogeochemical variables. The attenuation at λ = 710 nm was used as a proxy for particle concentration, TSM, whereas a novel parameter was adopted as an optical indicator for chlorophyll a (Chl-a) concentration, based on the local maximum of c(λ) observed at the long-wavelength side of the red band Chl-a absorption peak. In addition, since coloured dissolved organic matter (CDOM) has an important influence on the beam attenuation spectral shape and complementary measurements of particle size distribution were available, the beam attenuation spectral slope was used to analyze the CDOM content. Results were successfully compared with optical and biogeochemical variables from laboratory analysis of collocated water samples, and statistically significant correlations were found between the attenuation proxies and the biogeochemical variables TSM, Chl-a and CDOM. This outcome depicted the potential of high-frequency beam attenuation measurements as a simple, continuous and cost-effective approach for rapid detection of changes and patterns in biogeochemical properties in complex coastal environments.

Comparative Sensitivity Analysis Between two methods for Species Differentiation and Interspecies Cross Contamination in Animal Cell culture

Background and Aims : The present article focuses on design and development of a highly sensitive and convenient approach for rapid detection of animal species and cross contaminations quickly during cell cultures as most important document for manufacturing working cell bank system. This test is one of the four most important documents during implementing the banking system. By using this modified test also one of the major risks in cell culture laboratories, cross- contamination and misidentifications of cell lines will be also under test. Materials and Methods : A PCR _RFLP assay was optimized based on the use of a pair of primers that anneal to a portion the cytochrome b gene in all the species. The amplification product was digested with a panel of six restriction enzyme and the pattern derived was resolved on 3% high resolution agarose gel for 2 species, human & primate. As a control test we used from conventional method iso enzyme assay. Results : This protocol produced a unique restriction pattern and the origin of this animal cells resulted to be confirmed by this analysis. Its sensitivity in detecting interspecies cross contamination was at least 100 pg DNA/reaction, which was sufficient for detection of each species of DNA. Conclusion : For the last few years the RAZI vaccine and serum research institute in IRAN has been involved in developing such an ideal Iranian vaccine based on local Iranian material. The method developed in this study will provide a useful tool for the authentication of animal species comparable and most time consuming, cost benefit to other conventional analysis. Using the method (PCR-RFLP) developed during this research not only significant differences between human and non human also cross- contamination between different cell lines can simply distinguish.

Comparative Sensitivity Analysis Between two methods for Species Differentiation and Interspecies Cross Contamination in Animal Cell culture

Background and Aims : The present article focuses on design and development of a highly sensitive and convenient approach for rapid detection of animal species and cross contaminations quickly during cell cultures as most important document for manufacturing working cell bank system. This test is one of the four most important documents during implementing the banking system. By using this modified test also one of the major risks in cell culture laboratories, cross- contamination and misidentifications of cell lines will be also under test. Materials and Methods : A PCR _RFLP assay was optimized based on the use of a pair of primers that anneal to a portion the cytochrome b gene in all the species. The amplification product was digested with a panel of six restriction enzyme and the pattern derived was resolved on 3% high resolution agarose gel for 2 species, human & primate. As a control test we used from conventional method iso enzyme assay. Results : This protocol produced a unique restriction pattern and the origin of this animal cells resulted to be confirmed by this analysis. Its sensitivity in detecting interspecies cross contamination was at least 100 pg DNA/reaction, which was sufficient for detection of each species of DNA. Conclusion : For the last few years the RAZI vaccine and serum research institute in IRAN has been involved in developing such an ideal Iranian vaccine based on local Iranian material. The method developed in this study will provide a useful tool for the authentication of animal species comparable and most time consuming, cost benefit to other conventional analysis. Using the method (PCR-RFLP) developed during this research not only significant differences between human and non human also cross- contamination between different cell lines can simply distinguish.

Towards Translation of Discrete Frequency Infrared Spectroscopic Imaging for Digital Histopathology of Clinical Biopsy Samples.

Fourier transform infrared (FT-IR) spectroscopic imaging has been widely tested as a tool for stainless digital histology of biomedical specimens, including for the identification of infiltration and fibrosis in endomyocardial biopsy samples to assess transplant rejection. A major barrier in clinical translation has been the slow speed of imaging. To address this need, we tested and report here the viability of using high speed discrete frequency infrared (DFIR) imaging to obtain stain-free biochemical imaging in cardiovascular samples collected from patients. Images obtained by this method were classified with high accuracy by a Bayesian classification algorithm trained on FT-IR imaging data as well as on DFIR data. A single spectral feature correlated with instances of fibrosis, as identified by the pathologist, highlights the advantage of the DFIR imaging approach for rapid detection. The speed of digital pathologic recognition was at least 16 times faster than the fastest FT-IR imaging instrument. These results indicate that a fast, on-site identification of fibrosis using IR imaging has potential for real time assistance during surgeries. Further, the work describes development and applications of supervised classifiers on DFIR imaging data, comparing classifiers developed on FT-IR and DFIR imaging modalities and identifying specific spectral features for accurate identification of fibrosis. This addresses a topic of much debate on the use of training data and cross-modality validity of IR measurements. Together, the work is a step toward addressing a clinical diagnostic need at acquisition time scales that make IR imaging technology practical for medical use.

A rapid method for detecting objects with rectangular structures based on line correspondences

Rectangles commonly appear in man-made environments. This paper presents an approach for rapid detection of objects with rectangular structures. Considering that the object to be detected may have different textures, colors or other characteristics, only geometric structure information can be used for identification. Therefore, the key task in detecting rectangles is to acquire correct line correspondences. We analyze the reason why a basic frame of 2D homography computation and verification cannot meet the practical requirement for detection speed and then propose a two-step algorithm to solve the problem. First, we utilize a unified expression of homography between an unknown size rectangle and a quadrangle on the image to simplify the homography computation. Second, we propose a rotated cuboid bound constraint of the camera centre to rapidly remove incorrect homographies with unknown size parameters. Experiments with simulated and real data verify the correctness of our method.

Amperometric Determination of Sulfide by Glassy Carbon Electrode Modified with Hemin Functionalized Reduced Graphene Oxide

AbstractThis work describes a new approach for rapid detection of sulfide using a glassy carbon electrode (GCE) modified with hemin functionalized reduced graphene oxide (hemin‐rGO). The modified GCE was applied to the selective amperometric detection of sulfide at a working potential of 0.05 V (vs. Ag/AgCl) at pH 7.5, which gave a linear range of 0.002–0.212 mM, a sensitivity of 246.5 µA mM−1 cm−2, and a detection limit of 1.3 µM. The proposed method was applied in determination of sulfide‐spiked water, and the method was verified with recovery percentage of standard samples with an acceptable satisfaction.

Electrochemical determination of sulfide in fruits using alizarin–reduced graphene oxide nanosheets modified electrode

This study presents a new approach for rapid detection of sulfide using a glassy carbon electrode (GCE) modified with alizarin (Az) and reduced graphene oxide (rGO) nanosheets. The fabricate Az–rGO/GCE sensor shows a notable electrocatalytic activity to sulfide oxidation. The currents of anodic peak centered at +465mV in 0.2M pH 7.0 phosphate buffer were related linearly to the concentrations of sulfide, based on the cyclic voltammetric studies. The linear range was 0.002–3.28mM, and the detection limit was 1μM. The proposed method was applied in sulfide determination of hydrogen sulfide pretreated fruits, and the method was also verified with recovery studies.

PCR detection of Ralstonia solanacearum: A new approach for rapid detection of bacterium from infected plants

Ralstonia solanacearum (Smith) is a soil-borne plant pathogen responsible for causing bacterial wilt and having wide host range which includes monocots, dicots, annual plants/trees and shrubs. It is a most destructive disease of solanceaous crops and ginger in north eastern region of India. The pathogen is primarily present in soils as saprophytic bacterium and it has ability to survive for long periods of time in various natural habitats. The bacterium causes sudden wilting in plants and difficult to detect at the initial level as similar symptom may also occur with many fungal organisms like Fusarium spp. and Verticillium spp. An attempt was made to develop a PCR-based rapid method for detection of this pathogen. This method requires only 3-5 hours against the conventional methods which generally require minimum 3 days to detect the pathogen. The PCR uses previously reported primer pairs for fliC gene (Rsol_fliC), which amplify 400bp region of fliC gene. The bacterial ooze from infected tissues was directly used as a source of DNA. The amplified product was cloned and sequenced for confirmation. The PCR based method developed in this report is very simple, robust and inexpensive and was successfully tested on four infected samples and further validated on over 50 samples of tomato which were infected by R. solanacearum.

Small oscillation fault detection for a class of nonlinear systems with output measurements using deterministic learning

Early detection of small faults is an important issue in the literature of fault diagnosis. In this paper, for a class of nonlinear systems with output measurements, an approach for rapid detection of small oscillation faults is presented. Firstly, locally accurate approximations of unknown system dynamics and fault functions are achieved by combining a high gain observer and a deterministic learning (DL) theory. The obtained knowledge of system dynamics for both normal and fault modes is stored in constant RBF networks. Secondly, a bank of dynamical estimators are constructed for all the normal mode and oscillation faults. The knowledge obtained through DL is reused with a nonhigh-gain design. The occurrence of a fault can be detected if one of residual norms of a fault estimator becomes smaller than that of the normal estimator in a finite time. A rigorous analysis of the detectability properties of the proposed fault detection scheme is also given, which includes the fault detectability condition and the fault detection time. The attractions of the paper lie in that with output measurements, the knowledge of modeling uncertainty and nonlinear faults is obtained and then is utilized to enhance the sensitivity to small faults.

Multidrug resistant tuberculosis treatment in India.

Multidrug-resistant tuberculosis (MDR-TB) is posing a major public health threat as well as a big challenge to global efforts of tuberculosis control. The management of MDR-TB patients is difficult, expensive, challenging and quite often leads to treatment failure. To avoid further transmission, a comprehensive approach for rapid detection, proper treatment and effective public health measures must be ensured. It must also be emphasized that even optimal treatment of MDR-TB will not alone curb the epidemic. Efforts must be focused on the effective use of first-line drugs in every new case so as to prevent the ultimate emergence of MDR-TB.