Search

Phytoproducts are involved in various fields of industry. Small-molecule (Mw < 900 Da) organic compounds can be used to indicate the quality of plant samples in the perspective of efficacy by measuring the necessary secondary metabolites and in the perspective of safety by measuring the adulterant level of toxic compounds. The development of reliable detection methods for these compounds in such a complicated matrix is challenging. The lateral flow immunoassay (LFA) is one of the immunoassays well-known for its simplicity, portability, and rapidity. In this review, the general principle, components, format, and application of the LFA for phytoproducts are discussed. [ABSTRACT FROM AUTHOR]

Abstract Background Brucellosis is a serious zoonosis disease that frequently causes significant economic loss in animal husbandry and threatens human health. Therefore, we established a rapid, accurate, simple and sensitive fluorescent immunochromatographic strip test (ICST) based on quantum dots (QDs) for detection the antibodies of Brucella infection animals serum. Results The test strips were successfully prepared by quantum dot fluorescent microspheres (QDFM) as tracers, which were covalently coupled to an outer membrane protein of Brucella OMP22. The outer membrane protein OMP28 and monoclonal antibodies of OMP22 were separately dispensed onto a nitrocellulose membrane as test and quality control lines, respectively. The critical threshold for determining negative or positive through the ratio of the fluorescent signal of the test line and the control line (HT / HC) is 0.0492. The repeatability was excellent with an overall average CV of 8.78%. Under optimum conditions, the limit of detection was 1.05 ng/mL (1:512 dilution). With regard to the detection of brucellosis in 150 clinical samples, the total coincidence rate of ICST and Rose Bengal plate test (RBPT) was 97.3%, the coincidence rate of positive samples was 98.8%, the coincidence rate of negative samples was 95.3%, the sensitivity of RBPT is 1:32, and no cross reaction with the sera of other related diseases was observed. Conclusion In our present study, the QDFM has promising application for on-site screening of brucellosis owing to its high detection speed, high sensitivity, high specificity and low cost.

We designed and synthesized novel haptens to produce monoclonal antibodies (mAb) against vitamin B6 (VB6). A group-specific mAb (2F9) that recognized pyridoxine (PN), pyridoxamine (PM), and pyridoxal (PL) was prepared using a homologous strategy with 50% maximal inhibitory concentration (IC50) values of 106.60, 250.57, and 400.11 ng/mL, respectively. Based on this, a gold nanoparticles (AuNPs)-based immunochromatographic strip (ICS) test was established for the detection of VB6 in energy drinks and B-vitamin complex tablets. The developed ICS test results could be semi-quantitatively evaluated by the naked eye within 10 min, and displayed the visual limit of detection (vLOD) values of 250, 500, and 1,000 ng/mL for PN, PM, and PL, respectively. For quantitative analysis, the results obtained by strip reader, with calculated LOD values for PN, PM, and PL were 14.10, 55.58, and 56.25 ng/mL, respectively. Commercial energy drinks and B-vitamin complex tablet samples were detected by the strips and the results were confirmed with high-performance liquid chromatography. Overall, the developed AuNPs-based immunochromatographic sensor was suitable and promising for the group-specific recognition and rapid detection of VB6 in fortified foods and dietary supplements. [ABSTRACT FROM AUTHOR]

Fasciolosis is a zoonotic disease caused by Fasciola gigantica or F. hepatica infections, which are frequently occurring parasites in animals and humans. The present gold-standard diagnostic technique involves finding parasite eggs through microscopy. However, this method is also restricted due to low specificity and low sensitivity. An alternative to coprological diagnosis is the immunochromatographic strip (ICS) test, which is rapid, simple, convenient, and cost-effective, with high sensitivity and high specificity. Cathepsin L1H (CathL1H) is a cysteine protease secreted by F. gigantica, which is found in high amounts in newly excysted juvenile (NEJ) and juvenile stages. Cathepsin L1H plays an important role in both the immune response to invading pathogens and in the ability of some pathogens to evade the host immune system. The present study aims to develop an ICS test and detect antibodies against CathL1H in mice and cattle serum using the recombinant F. gigantica Cathepsin L1H (rFgCathL1H) and rabbit anti-rFgCathL1H antibody. The F. gigantica-infected serum and non-infected serum of mice and cattle were tested using the ICS test. Moreover, the strip results were confirmed with an indirect enzyme-linked immunosorbent assay (indirect ELISA). The relative sensitivity, specificity, and accuracy of the ICS strip were 97.5, 99.99, and 99.00%, respectively. Therefore, these data suggest that the ICS method could be used to detect F. gigantica antibodies to highly enhance throughput, reduce costs, and determine the best alternative on-site method.

Objective: To produce, purify, and characterize a polyclonal antibody against acrylamide (anti-AA) for an application to immunochromatographic strip tests for AA. Material and Methods: Polyclonal anti-AA was prepared by injecting N-acryloxysuccinimide-conjugated bovine serum albumin hapten-antigen into New Zealand white rabbits. The antibody was purified using protein A, characterized using sodium dodecyl sulfate-polyacrylamide gel elec¬trophoresis (SDS-PAGE) and conjugated with gold nanoparticles (AuNP). The conjugated antibody was then characterized using UVVis and FTIR spectroscopy and transmission electron microscopy (TEM). Immunochromatographic strip tests were performed using sample pads, conjugated pads, test zones, control zones, and absorbent pads. Strip tests were finally validated using standard AA solutions followed by the application of various concentrations of coffee samples. Results: Using SDS-PAGE, the purified anti-AA antibody was resolved at 50 and 25 kDa, indicat¬ing the presence of heavy and light chains, respectively. The conjugation of anti-AA with AuNP was confirmed using wavelength shifts in UVVis and FTIR spectra, and TEM analyses revealed increased diameters of AuNPs after conjugation. The immunochromatographic strip test was sen-sitive to 1 mgml−1 standard AA. Various concentrations of coffee samples resulted in red color differences in the test zone. High and low coffee concentrations produced thick and thin red lines, respectively. Conclusion: Purified anti-AA can be conjugated with AuNP to produce strip tests for detecting AA in coffee samples. The present immunochromatographic strip tests quantitatively showed increasing intensities of red lines with increasing AA concentrations. [J Adv Vet Anim Res 2019; 6(3.000): 366-375]

Nickel hydroxide nanoparticles [Ni(OH)2-NPs] synthesized by a complexation-precipitation method under hydrothermal conditions were employed as a probe in immunochromatographic strip tests for the selective detection of melamine. The characterization of Ni(OH)2-NPs and their conjugation to anti-melamine antibody (anti-MEL) were performed using a UV- visible spectrophotometer, Fourier transform infrared (FTIR) spectroscopy, and TEM. On the basis of the green line intensity, the strip test can selectively detect melamine at a minimum concentration of 25 ppm. Our results suggest that this system is promising for the quantitative detection of melamine. [ABSTRACT FROM AUTHOR]

Background: Brucellosis is a serious zoonosis disease that frequently causes significant economic loss in animal husbandry and threatens human health. Therefore, we established a rapid, accurate, simple and sensitive fluorescent immunochromatographic strip test (ICST) based on quantum dots (QDs) for detection the antibodies of Brucella infection animals serum. Results: The test strips were successfully prepared by quantum dot fluorescent microspheres (QDFM) as tracers, which were covalently coupled to an outer membrane protein of Brucella OMP22. The outer membrane protein OMP28 and monoclonal antibodies of OMP22 were separately dispensed onto a nitrocellulose membrane as test and quality control lines, respectively. The critical threshold for determining negative or positive through the ratio of the fluorescent signal of the test line and the control line (HT / HC) is 0.0492. The repeatability was excellent with an overall average CV of 8.78%. Under optimum conditions, the limit of detection was 1.05 ng/mL (1:512 dilution). With regard to the detection of brucellosis in 150 clinical samples, the total coincidence rate of ICST and Rose Bengal plate test (RBPT) was 97.3%, the coincidence rate of positive samples was 98.8%, the coincidence rate of negative samples was 95.3%, the sensitivity of RBPT is 1:32, and no cross reaction with the sera of other related diseases was observed. Conclusion: In our present study, the QDFM has promising application for on-site screening of brucellosis owing to its high detection speed, high sensitivity, high specificity and low cost. [ABSTRACT FROM AUTHOR]

Here, two monoclonal antibodies (MAbs) specific to different epitopes on ToxB, a toxin produced by Vibrio parahaemolyticus that causes acute hepatopancreatic necrosis disease (VPAHPND), were employed to develop a rapid strip test. One MAb was conjugated to colloidal gold to bind to ToxB at the application pad, and another MAb was used to capture colloidal gold MAb–protein complexes at the test line (T) on the nitrocellulose strip. To validate test performance, a downstream control line (C) of goat anti‐mouse immunoglobulin G antibody was used to capture the free colloidal gold conjugate MAb. The sample in the application buffer could be applied directly to the application well, and the test result was obtained within 15 min. The sensitivity of the kit is approximately 6.25 µg/ml of toxin, which was equivalent to the toxin produced by approximately 107 cfu/ml of bacteria. This kit is convenient and easy to use since it can be used to identify VPAHPND directly using a single colony of bacteria grown on agar culture plates. Because of its high specificity and simplicity, as well as not being reliant on sophisticated equipment or specialized skills, this strip test could be used by farmers for surveillance for ToxB‐producing bacteria. [ABSTRACT FROM AUTHOR]

The Lateral Flow Immunoassay (LFIA) is by far one of the most successful analytical platforms to perform the on-site detection of target substances. LFIA can be considered as a sort of lab-in-a-hand and, together with other point-of-need tests, has represented a paradigm shift from sample-to-lab to lab-to-sample aiming to improve decision making and turnaround time. The features of LFIAs made them a very attractive tool in clinical diagnostic where they can improve patient care by enabling more prompt diagnosis and treatment decisions. The rapidity, simplicity, relative cost-effectiveness, and the possibility to be used by nonskilled personnel contributed to the wide acceptance of LFIAs. As a consequence, from the detection of molecules, organisms, and (bio)markers for clinical purposes, the LFIA application has been rapidly extended to other fields, including food and feed safety, veterinary medicine, environmental control, and many others. This review aims to provide readers with a 10-years overview of applications, outlining the trends for the main application fields and the relative compounded annual growth rates. Moreover, future perspectives and challenges are discussed.

Adult-onset immunodeficiency syndrome (AOID) patients with autoantibodies (autoAbs) against interferon-gamma (IFN-γ) generally suffer from recurrent and recalcitrant disseminated non-tuberculous mycobacterial diseases. Since the early stages of AOID do not present specific symptoms, diagnosis and treatment of the condition are not practical. A simplified diagnostic method for differentiating AOID from other immunodeficiencies, such as HIV infection, was created. Anti-IFN-γ is generally identified using enzyme-linked immunosorbent assay (ELISA), which involves an instrument and a cumbersome process. Recombinant IFN-γ indirectly conjugated to colloidal gold was used in the modified immunochromatographic (IC) strips. The biotinylated-IFN-γ was incorporated with colloidal-gold-labeled 6HIS-maltose binding protein-monomeric streptavidin (6HISMBP-mSA) and absorbed at the conjugate pad. The efficacy of the IC strip upon applying an anti-IFN-γ autoAb cut-off ELISA titer of 2500, the sensitivity and specificity were 84% and 90.24%, respectively. When a cut-off ELISA titer of 500 was applied, the sensitivity and specificity were 73.52% and 100%, respectively.

Individual drug concentration data can be a valuable tool for the clinical management of antiretroviral therapy (ART) for the treatment of HIV infection. High performance liquid chromatography (HPLC) based assays are currently the gold standard for drug measurement but its high cost and requirement of technical expertise limits its widespread use. Simpler user-friendly and inexpensive detection assays are needed. A novel immunochromatographic (IC) strip test to detect HIV-1 protease inhibitors (PIs) was fabricated by combining the proteolysis activity of HIV-protease (PR) and an immunochromatographic reaction. The PIs-IC strip cut-off to detect lopinavir (LPV) concentrations was set at 1,000 ng mL−1. We evaluated this novel PIs-IC strip for the semi-quantification of HIV PIs in plasma samples collected from healthy subjects and HIV-infected patients receiving antiretroviral treatment with and without LPV. LPV plasma drug levels were quantified by HPLC and evaluated (blinded to the HPLC results) using the PIs-IC strip. Results of plasma samples tested using the PIs-IC strip were available within 5 min. Using the PIs-IC strip test the accuracy, specificity and sensitivity were 97.8%, 97.1%, and 100%, respectively, compare to the gold-standard assay, to detect LPV in human plasma samples. This novel PIs-IC strip test could be used as a simple tool for the rapid monitoring of PIs levels in HIV-infected patients, although further clinical evaluation is needed. Image 1 • Semi-quantitative IC strip is suitable for detecting the therapeutic PIs level in plasma of HIV-infected patients receiving ART. • The IC strip is capable of monitoring any HIV PIs. • The IC strip can be applied for screening the lead compounds for discovering of novel PIs. [ABSTRACT FROM AUTHOR]

Objective: To produce, purify, and characterize a polyclonal antibody against acrylamide (anti-AA) for an application to immunochromatographic strip tests for AA. Material and Methods: Polyclonal anti-AA was prepared by injecting N-acryloxysuccinimideconjugated bovine serum albumin hapten-antigen into New Zealand white rabbits. The antibody was purified using protein A, characterized using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and conjugated with gold nanoparticles (AuNP). The conjugated antibody was then characterized using UV-Vis and FTIR spectroscopy and transmission electron microscopy (TEM). Immunochromatographic strip tests were performed using sample pads, conjugated pads, test zones, control zones, and absorbent pads. Strip tests were finally validated using standard AA solutions followed by the application of various concentrations of coffee samples. Results: Using SDS-PAGE, the purified anti-AA antibody was resolved at 50 and 25 kDa, indicating the presence of heavy and light chains, respectively. The conjugation of anti-AA with AuNP was confirmed using wavelength shifts in UV-Vis and FTIR spectra, and TEM analyses revealed increased diameters of AuNPs after conjugation. The immunochromatographic strip test was sensitive to 1 mgml-1 standard AA. Various concentrations of coffee samples resulted in red color differences in the test zone. High and low coffee concentrations produced thick and thin red lines, respectively. Conclusion: Purified anti-AA can be conjugated with AuNP to produce strip tests for detecting AA in coffee samples. The present immunochromatographic strip tests quantitatively showed increasing intensities of red lines with increasing AA concentrations. [ABSTRACT FROM AUTHOR]

Pueraria candollei (P. candollei) is a traditional Thai herb widely used for estrogen replacement therapy because it contains many unique chromenes that possess potent estrogenic activity, one of which is known as isomiroestrol. Since isomiroestrol is a promising compound that is solely present in P. candollei, it can be used as an identifying marker for standardization of P. candollei. Here, we developed a lateral-flow immunochromatographic strip (ICS) test using a colloidal gold nanoparticle-conjugated anti-isomiroestrol monoclonal antibody (12C1-mAb) for the detection of isomiroestrol in plant samples and products of P. candollei. The advantages of the developed ICS over an enzyme-linked immunosorbent assay are its simplicity and rapidity, as the ICS test can be completed 15 min after dipping the strip into the analyte solution. The detectable concentration of isomiroestrol was 7.0 µg/mL. Considering the demand for the standardization of P. candollei due to concerns regarding its quality, our ICS test using isomiroestrol as an identifying marker would be effective and useful to assess the presence of isomiroestrol. [ABSTRACT FROM AUTHOR]

In this study, we report the simultaneous use of gold and silver nanoparticles to set a multicolor multiplex lateral flow immunoassay (xLFIA). Silver nanoparticles (AgNPs), spherical in shape and characterized by a brilliant yellow color, were obtained by a new viable one-step synthetic protocol. AgNPs were stable over time and acceptably robust to conditions used for fabricating LFIA devices. These AgNPs were employed as a colorimetric probe in combination with two different kinds of gold nanoparticles (AuNPs) to set a visual xLFIA for detecting allergens. Surface plasmon resonance peaks of probes (AgNPs, spherical and desert rose-like AuNPs) were centered at 420, 525, and 620 nm, respectively. Therefore, the xLFIA output was easily interpreted through a "yellow magenta cyan (YMC)" color code. The prospect of the YMC xLFIA was demonstrated by simultaneously detecting three major allergens in bakery products. Antibodies directed towards casein, ovalbumin, and hazelnut allergenic proteins were individually adsorbed onto metal nanoparticles to produce three differently colored specific probes. These were inserted in a LFIA comprising three lines, each responsive for one allergen. The trichromatic xLFIA was able to detect allergenic proteins at levels as low as 0.1 mg/l and enabled the easy identification of the allergens in commercial biscuits based on the color of the probes. Graphical Abstract [ABSTRACT FROM AUTHOR]

Abstract A multiplex Lateral Flow Immunoassay was developed based on the use of a single Test line and multicolour gold nanoparticles (GNPs) as signal reporters. Red and blue GNPs were linked to antibodies directed towards two different analytes and included in a typical lateral flow immunoassay configuration, in which the Test line was formed by the mixture of two antigens. As a result of the immunoreactions occurring at the Test zone, diverse combinations of red and blue GNPs labels were captured. Therefore, the Test line assumed different colours depending on which – and how much – analyte is present in the sample. The multiplexing capability of the 'colour-encoded assay' is illustrated by the simultaneous detection of aflatoxin B1 (AFB1) and type-B fumonisins (FMs) in wheat and food products that made with wheat. Reproducible detection of AFB1 and FMs contamination in raw and processed food was achieved with visual cut-off levels at 1 ng mL−1 and 50 ng mL−1, respectively. The contaminant was identified based on the colour of the label according with a specific colour code. Furthermore, strips images were acquired by means of a common smartphone and analysed through RGB data analysis providing semi-quantitative detection of the two mycotoxins. Graphical abstract fx1 Highlights • A novel lateral flow assay using dual colour gold nanoparticles is described. • Aflatoxins and fumonisins were simultaneously detected in cereal-based food. • A single Test line was fabricated that was sensitive to both mycotoxins. • A colour code allowed for detecting mycotoxins and discriminating among the two Smartphone-based detection provided quantification through RGB data analysis. [ABSTRACT FROM AUTHOR]

Abstract Background Theileria uilenbergi and T. luwenshuni are tick-borne protozoan parasites, transmitted by Haemaphysalis qinghaiensis and H. longicornis, respectively. They are the main causative agents of theileriosis in small ruminants in China. The disease has resulted in severe economic losses and hindered the development of sheep and goat husbandry industry in the endemic regions. Methods In this study, a colloidal gold-based immunochromatographic strip (ICS) was developed for the detection of T. uilenbergi and/or T. luwenshuni infections. A recombinant T. uilenbergi immunodominant protein (rTuIP) was used as antigen for the ICS. The nitrocellulose membrane was incubated with rTuIP on the test (T) line and anti-rTuIP antiserum on the control (C) line, respectively. The rTuIP conjugated to colloidal gold particles was used as the detection system for visualization of the lines. Then the sample pad, conjugate pad, nitrocellulose membrane and absorbent pad were assembled onto a backing plate in the appropriate order. Results The ICS was able to detect antibodies in the sera of animals experimentally infected with T. uilenbergi from 14 to 85 days. It also reacted with the serum from T. luwenshuni infected sheep. However, there was no cross-reactivity with sera from animals infected with Babesia motasi and Anaplasma ovis. Comparison of the ICS with the rTuIP antigen based indirect enzyme-linked immunosorbent assays (ELISA) using test field samples showed good correlations with 93.1 % (81/87) sensitivity and 100 % (40/40) specificity, respectively, with an almost perfect agreement (Kappa = 0.895, P

Aim: The present study was undertaken to detect the presence of canine parvovirus (CPV) in fecal samples of diarrheic dogs by conventional polymerase chain reaction (PCR) and immunochromatographic (IC) strip test and to compare the diagnostic potential of these tests. Materials and Methods: A total of 50 fecal samples collected from diarrheic dogs suspected for CPV infection were subjected to PCR using CPV-555 primer amplifying the gene coding for the VP1 protein. These samples were also tested by IC strip test using a commercial rapid Ag test kit. The results were statistically analyzed using McNemar test. Results: A total of 22 samples (44%) were detected as positive by PCR, which yielded a specific amplicon of 583 bp. In IC strip test, 18 (36%) samples were found to be positive. The sensitivity of the test as compared to PCR was found to be 72.22% and specificity was 92.86%. Positive predictive value and negative predictive value of IC strip test was found to be 88.89% and 81.25%, respectively. Statistical analysis of the results of PCR and IC assay using McNemar test revealed no significant difference (p>0.05). Conclusion: The IC strip test could be employed as a rapid field level diagnostic tool for the diagnosis of canine parvoviral diarrhea.

A rapid, simple, and sensitive fluorescent immunochromatographic strip test (ICST) based on quantum dots (QDs) has been developed to detect 1-aminohydantoin (AHD), a major metabolite of nitrofurantoin in animal tissues. To achieve this, QD-labeled antibody conjugates, which consist of CdSe/ZnS QDs and monoclonal antibodies, were prepared by an activated ester method. Under optimal conditions, with the nitrophenyl derivative of AHD as the target, the ICST had a linear range from 0.1 to 100 ng/mL, with a correlation coefficient of 0.9656 and a 50% inhibitory concentration of 4.51 ng/mL. The limit of detection was 0.14 ng/g, which was below the minimum required performance limit of 1 μg/kg for AHD established by the European Commission. The recoveries for AHD ranged from 81.5% to 108.2%, with coefficients of variation below 13%, based on intraday and interday analysis. Furthermore, for AHD in real samples, the ICST showed high reliability and high correlation with liquid chromatography-tandem mass spectrometry (correlation coefficient of 0.9916). To the best of our knowledge, this is the first report of a novel and sensitive method based on a fluorescent ICST to detect AHD below the minimum required performance limit. The ICST demonstrated high reliability, and could be ideally suited for rapid, simple, and on-site screening of AHD contamination in animal tissues. [ABSTRACT FROM AUTHOR]

Spiroplasma eriocheiris is an emerging pathogen in freshwater crustaceans. In recent years, Eriocheir sinensis, Procambarus clarkii, Litopenaeus vannamei, Macrobrachium rosenbergii and Macrobrachium nipponense had been infected by this pathogen in China. An immunochromatographic strip test using gold nanoparticles was developed for rapidly detecting this pathogen. The strip test based on the principle of sandwich immunoassay by the specific combination between the pathogen and polyclonal antibody on a nitrocellulose membrane. Positive samples were displayed as red lines at the test and control zones of the nitrocellulose membrane, while negative samples resulted in a red line only at the control zone. The limit of detection was proved to be 106 Color Change Unit/ml. The test strip could be visually detected within 15 min and do not have cross-reaction with other aquatic bacteria. This test strip allows on-site rapid detection of S. eriocheiris in crustacean without the requirement of specialized equipment and professional personnel. The one-step test strips developed in our study had high sensitivity, specificity, reproducibility and stability. In conclusion, this method was proved to be convenient, feasible, rapid and effective for detecting S. eriocheiris. [ABSTRACT FROM AUTHOR]

A rapid, portable, and semi-quantitative immunochromatographic strip was developed for rapid and visual detection of alternariol monomethyl ether (AME). For this purpose, the anti-AME monoclonal antibody (mAb) was prepared and identified. AME coupled to bovine serum albumin (BSA) via methyl 4-bromobutanoate was prepared as immunogen. The recoveries of AME in spiked cherry and orange fruits determined by competitive ELISA were 86.1% and 80.7%, respectively. A colloidal gold nanoparticle (CGN) and CGNs-mAb conjugate were synthesized, and on this basis, a competitive colloidal gold immunochromatographic strip was developed and applied to the detection of AME toxin in fruit samples. The intensity of red density of the test line (T line) is inversely proportional to AME concentration in the range 0.1-10 ng/mL. The visual limit of detection (LOD) of AME was found to be about 10 ng/mL. The semi-quantitative detection can be completed in 10 min. Moreover, the immunochromatographic strip has lower cross-reactivity with AME analogues, and it has a good stability performance (following 3 months of storage). Hence, the colloidal gold immunochromatographic strip could be used as a semi-quantitative tool for the on-site, rapid, and visual detection of AME in fruit. [ABSTRACT FROM AUTHOR]

Harringtonine (HT) is a natural compound, which is mainly produced by the genus Cephalotaxus , and has been clinically utilized in China for the treatment of acute leukemia and lymphoma. However, the amounts of HT in the Cephalotaxus species are very small; therefore, plant tissue cultures have been focused upon to enhance HT production. Qualitative/quantitative methods for HT detection are required to screen superior cell lines. We developed a one-step indirect competitive immunochromatographic assay (ICA) using colloidal gold nanoparticles conjugated with highly specific monoclonal antibodies against HT (MAb 1D2) for simple, rapid, and sensitive detection of HT in plant samples. This ICA can be completed in 15 min after dipping the strip into analytes with a limit of detection of ∼313 ng/mL. In developed ICA, fiber pad which is usually used for conventional ICA, was not used to shorten the time for preparing chromatographic strip, resulting in a decrease in the volume of valuable analytes (20 μL). Considering simplicity, rapidity, and sensitivity of the developed ICA, this study could be applied to a fieldwork study for finding new natural resources containing HT. [ABSTRACT FROM AUTHOR]

Two monoclonal antibodies (MAbs) specific to different epitopes on ICP11, a non-structural protein of white spot syndrome virus (WSSV), were employed to develop a highly sensitive immunochromatographic strip test (ICP11 strip test). One MAb (WI-11) was conjugated to colloidal gold to bind to ICP11 and another MAb (WI-16) was used to capture colloidal gold MAb-protein complexes at the test line (T) on the nitrocellulose strip. A downstream control line (C) of goat anti-mouse immunoglobulin G (GAM) antibody was used to capture the free colloidal gold conjugated MAb to validate the test performance. Homogenate of shrimp sample in application buffer could be applied directly to the application well and the test result was obtained within 15 min. The sensitivity of the kit is 40 times more sensitive than the detection limit of previously reported strip test using MAbs specific to VP28, and approximately 400 times more sensitive than that of Shrimple®, but approximately 50 times less sensitive than that of one-step PCR. For experimentally WSSV-infected shrimps, the ICP11 strip could detect WSSV as early as 12–18 h post infection. Due to its high specificity, simplicity and no requirement on sophisticated equipment or specialized skills, the strip test could be adopted to surveillance of early WSSV infection at the pond site. [ABSTRACT FROM AUTHOR]

Elephant endotheliotropic herpesvirus (EEHV) is the causative agent of EEHV-hemorrhagic disease (EEHV-HD) in elephants worldwide. This disease is highly virulent and a predominant cause of fatalities in young Asian elephants. Rapid diagnosis and aggressive therapies have been determined to be a key strategy in the successful treatment of this disease. Herein, we have developed the immunochromatographic strip test for EEHV detection. Accordingly, 31.2 kDa of partial EEHV DNA polymerase (DNApol) protein was expressed in Escherichia coli and used to generate rabbit polyclonal anti-EEHV DNApol antibodies. These were then used to develop an ICS test for EEHV antigen detection using the double-antibody sandwich colloidal gold method. Anti-EEHV DNApol antibodies conjugated with 40 nm colloidal gold solution were used as a detector, while rabbit anti-EEHV DNApol and goat anti-rabbit IgG antibodies immobilized on the nitrocellulose membrane were used as the test and control lines, respectively. The test had a detection limit of 1.25 × 105 viral genome copies (vgc)/mL of EEHV obtained from blood samples. Moreover, no specialized equipment or laboratory infrastructure was required in the administration of this test. This developed ICS test for EEHV antigen detection can be used in field application for the rapid detection of EEHV in resource-limited environments. • A novel immunochromatographic strip (ICS) test for rapid EEHV antigen detection in Asian elephants was developed in the present study. • Anti-EEHV DNApol antibodies conjugated with colloidal gold solution were used as a detector, while rabbit anti-EEHV DNApol was used at the test line. • This newly developed test had a limit of detection (LOD) value of EEHV in the whole blood samples of 125,000 vgc/mL and could be applied to saliva sample. • No special laboratory equipment required in the administration of this test. [ABSTRACT FROM AUTHOR]

An immunochromatographic strip test with enhanced sensitivity for the detection of infectious myonecrosis virus (IMNV) was developed using three monoclonal antibodies specific to N- and C-termini fragments of IMNV capsid protein. This strip test can detect IMNV with 20 times higher sensitivity than the previous test strip and approximately 50 times lower than that of one-step RT-PCR. The shrimp sample can be heat-treated to augment the release of antigen from the muscular tissue and ensure the sterilization of the sample. Due to its high specificity, field friendly and rapid result, this test strip is suitable for surveillance of IMNV outbreaks and confirmation of IMNV infection in shrimp farming. Statement of relevance The IMNV strip test will help farmers to monitor IMNV infection during shrimp culture. The test kit has sensitivity of approximately 50 times lower than that of one-step RT-PCR. [ABSTRACT FROM AUTHOR]

Fasciolosis is a zoonotic disease caused by Fasciola gigantica or F. hepatica infections, which are frequently occurring parasites in animals and humans. The present gold-standard diagnostic technique involves finding parasite eggs through microscopy. However, this method is also restricted due to low specificity and low sensitivity. An alternative to coprological diagnosis is the immunochromatographic strip (ICS) test, which is rapid, simple, convenient, and cost-effective, with high sensitivity and high specificity. Cathepsin L1H (CathL1H) is a cysteine protease secreted by F. gigantica , which is found in high amounts in newly excysted juvenile (NEJ) and juvenile stages. Cathepsin L1H plays an important role in both the immune response to invading pathogens and in the ability of some pathogens to evade the host immune system. The present study aims to develop an ICS test and detect antibodies against CathL1H in mice and cattle serum using the recombinant F. gigantica Cathepsin L1H (rFgCathL1H) and rabbit anti-rFgCathL1H antibody. The F. gigantica -infected serum and non-infected serum of mice and cattle were tested using the ICS test. Moreover, the strip results were confirmed with an indirect enzyme-linked immunosorbent assay (indirect ELISA). The relative sensitivity, specificity, and accuracy of the ICS strip were 97.5, 99.99, and 99.00%, respectively. Therefore, these data suggest that the ICS method could be used to detect F. gigantica antibodies to highly enhance throughput, reduce costs, and determine the best alternative on-site method.

Aim: The present study was undertaken to detect the presence of canine parvovirus (CPV) in fecal samples of diarrheic dogs by conventional polymerase chain reaction (PCR) and immunochromatographic (IC) strip test and to compare the diagnostic potential of these tests. Materials and Methods: A total of 50 fecal samples collected from diarrheic dogs suspected for CPV infection were subjected to PCR using CPV-555 primer amplifying the gene coding for the VP1 protein. These samples were also tested by IC strip test using a commercial rapid Ag test kit. The results were statistically analyzed using McNemar test. Results: A total of 22 samples (44%) were detected as positive by PCR, which yielded a specific amplicon of 583 bp. In IC strip test, 18 (36%) samples were found to be positive. The sensitivity of the test as compared to PCR was found to be 72.22% and specificity was 92.86%. Positive predictive value and negative predictive value of IC strip test was found to be 88.89% and 81.25%, respectively. Statistical analysis of the results of PCR and IC assay using McNemar test revealed no significant difference (p>0.05). Conclusion: The IC strip test could be employed as a rapid field level diagnostic tool for the diagnosis of canine parvoviral diarrhea. [ABSTRACT FROM AUTHOR]

Here we developed a sensitive, specific, and rapid immunochromatographic strip test for the detection of Cronobacter. Silica-coated magnetic nanoparticles were used to separate nucleic acid from Cronobacter lysate and eliminate the interference of food matrices successfully. A couple of 5′-end labeled probes, which was complementary to the 16S ribosomal DNA of Cronobacter, was used to hybridize with the nucleic acid. The hybrid product, labeled with digoxigenin on one side and biotin on the other side, was directly submitted to the immunochromatographic strip test and the anti-digoxigenin monoclonal antibody was immobilized on nitrocellulose membrane in the test line. The visualization was achieved by gold nanoparticles conjugated to streptavidin, and double red bands appearing in both test and control line indicated a positive result of the presence of Cronobacter in testing sample. The detection limit was 107cfumL-1 in pure culture. After silica-coated magnetic nanoparticles treatment, the detection limit was 105 and 106cfumL-1 in pure culture and powdered infant formula, respectively, and maintained stable even under the interference of 108cfumL-1Salmonella typhimurium. Furthermore, 100 positive powdered infant formula samples spiked 108cfumL-1Cronobacter and 20 negative samples with none bacteria were tested by the strip, and the sensitivity and specificity of the test were both as high as 100%. This approach showed promise for microbial detection concerning food safety or clinical diagnosis. [ABSTRACT FROM AUTHOR]

An immunochromatographic strip test based on the complex reaction of antigen-antibody (melamine-antimelamine) was developed for quantitative detection of melamine. Gold nanoparticles (AuNP) were used to form AuNP-labeled antibody, which then acted as a biosensor. Melamine quantification was performed by the determination of AuNP using anodic stripping voltammetry technique with a boron-doped diamond as the working electrode. With sample volume of 100μL and immunoreaction time of 7 min, the developed immunochromatographic strip test produced a linear calibration curve for melamine concentration range of 0-0.6 mg/L, with detection limit of 0.1 mg/L and RSD of ~5%. Furthermore, negative results were obtained for samples containing cyanuric acid and urea, indicating that the developed immunochromatographic strip test has potential for selective and quantitative detection of melamine. Strip test berbasis imunokromatografi berdasarkan reaksi pembentukan kompleks antigen-antibodi (melamin-antimelamin) dikembangkan untuk mendeteksi melamin secara kuantitatif. Nanopartikel emas (AuNP) digunakan sebagai label pada antibodi untuk membentuk antibodi berlabel AuNP yang kemudian berfungsi sebagai biosensor. Kuantifikasi melamin diperoleh dengan menentukan konsentrasi AuNP menggunakan teknik anodic stripping voltammetry. Boron-doped diamond digunakan sebagai elektroda kerja. Dengan volume sampel 100μL dan waktu imunoreaksi 7 menit, strip test menghasilkan kurva linier pada kisaran konsentrasi 0-0,6 mg/L dengan batas deteksi 0.1 mg/L dan RSD ~5%. Selain itu hasil negatif diperoleh ketika strip test diaplikasikan pada sampel yang mengandung asam sianurat dan urea, hal tersebut mengindikasikan bahwa strip test yang dikembangkan dapat digunakan sebagai pendeteksi melamin secara selektif dan kuantitatif. [ABSTRACT FROM AUTHOR]

The article focuses on a study that evaluated an immunochromatographic (IC) strip assay for Hemoglobin (Hb) Bart's disease (HB) as a routine screening test for alpha thalassaemia in area with a high prevalence of thalassaemia and haemoglobinopathies. As mentioned, the result showed a high sensitivity for screening for alpha-thalassaemia using IC strip assay for HB, and the article mentions that this test in association with conventional methods can significantly reduce cases for DNA analysis.

Electrochemical detection of hydrogen peroxide (H2O2) at a platinum-deposited boron doped diamond was studied for an application in melamine strip test. Deposition of Pt particles at a boron-doped diamond surface was performed using cyclic voltammetry method. The method was also used for electrochemical measurements. The oxidation-reduction peak currents of H2O2 at + 0.6 V and - 0.1 V (vs. Ag/AgCl), respectively were found to be linear in the concentration range of 0.05--20 mM (R² = 0.99). Linearity was also observed to be dependent on horseradish peroxidase (HRP) concentration in the constant concentration of H2O2. The method was then applied in immunochromatographic strip test for melamine detection to determine the activity of HRP labeled at melamine antibody. Taking an assumption that the activity of HRP was equivalent to melamine concentration, linearity of the current responses to the concentrations of standard melamine solutions in the range of 5-100 µg/ml could be achieved. Limit of detection of 0.51 µg/ml was estimated. The obtained results demonstrated that the designed biosensor for detection of H2O2 could be applied for the quantitative and selective detection of melamine. [ABSTRACT FROM AUTHOR]

The foot-and-mouth disease (FMD) is the most important transboundary viral disease of livestock in the international context, because of its extreme contagiousness, widespread diffusion, and severe impact on animal trade and animal productions. The rapid and on-field detection of the virus responsible for the FMD represents an urgent demand to efficiently control the diffusion of the infection, especially in low resource setting where the FMD is endemic. Colorimetric lateral flow immunoassay (LFIA) is largely used for the development of rapid tests, due to the extreme simplicity, cost-effectiveness, and on-field operation. In this work, two multiplex LFIA devices were designed for the diagnosis of FMD and the simultaneous identification of major circulating serotypes of the FMD virus. The LFIAs relied on the sandwich-type immunoassay and combined a set of well-characterised monoclonal antibodies (mAb) pairs. One LFIA aimed at detecting and identifying O, A and Asia-1 serotypes, the second device enabled the detection and differentiation of the SAT 1 and SAT 2 serotypes. Both devices also incorporated a broad-specific test line reporting on infection from FMDV, regardless the strain and the serotype involved. Accordingly, five and four reactive zones were arranged in the two devices to achieve a total of six simultaneous analyses. The development of the two multiplex systems highlighted for the first time the relevance of the mAb positioning along the LFIA strip in connection with the use of the same or different mAb as capture and detector ligands. In fact, the excess of detector mAb typically employed for increasing the sensitivity of sandwich immunoassay induced a new type of hook effect when combined with the same ligand used as the capture. This effect strongly impacted assay sensitivity, which could be improved by an intelligent alignment of the mAb pairs along the LFIA strip. The analytical and diagnostic performances of the two LFIAs were studied by testing reference FMDV strains grown in cell cultures and some representative field samples (epithelium homogenates). Almost equivalent sensitivity and specificity to those of a reference Ag-ELISA kit were shown, except for the serotype SAT 2. These simple devices are suitable in endemic regions for in-field diagnosis of FMD accompanied by virus serotyping and, moreover, could be deployed and used for rapid confirmation of secondary outbreaks after FMD incursions in free-areas, thus contributing to promptly implement control measures. [Display omitted] • Two multiplex lateral flow devices were developed for diagnosing foot-and-mouse disease. • The LFDs enabled detecting the FMD virus and differentiate three and two virus types. • The LFD were applied to for the point-of-care detection of FMDV isolates from outbreaks. • Diagnostic sensitivity and specificity were in perfect agreement with the reference ELISA. [ABSTRACT FROM AUTHOR]

Campylobacter jejuni is a worldwide foodborne pathogen recognized as a leading cause of human gastrointestinal enteritis. A rapid, sensitive, and specific method is required to monitor food and water in cases of contamination by this pathogen. This report presents a novel immunochromatographic test (ICT) using fluorescent microspheres labeled with polyclonal antibodies of C. jejuni as the capture reagent dispensed onto the conjugate pad. Polyclonal antibodies against the outer membrane protein PEB1 of C. jejuni were used as the detective reagent at the test line, whereas the goat anti-rabbit IgG was used on the control line. PEB1 was obtained by gene cloning and expression to prepare its antibody. In this study, a simple and rapid ICT is reported for detecting C. jejuni for the first time with a detection limit of 10 CFU/ mL. [ABSTRACT FROM AUTHOR]

Abstract: An immunochromatographic strip test is described for detection of the polyhedrin protein of Penaeus monodon nucleopolyhedrovirus (PemoNPV). The test employs one monoclonal antibody (MAb MBV5) conjugated to colloidal gold to bind to polyhedrin protein and a 1:1:1 mixture of 3 other MAbs (MBV8, 14 and 21) to capture colloidal-gold MAb–protein complexes at a test (T) line on the nitrocellulose strip. A downstream control (C) line of goat anti-mouse immunoglobulin G (GAM) antibody is used to capture excess free colloidal-gold conjugated MBV5 to validate test performance. Heating of homogenates of PemoNPV-infected P. monodon postlarvae prepared in PBS for 30min was necessary to maximize T line color intensity, and homogenates of infected postlarvae could still be scored as PemoNPV-positive when diluted 1:64. A strip test result was obtained within 15min of sample application, and although about 200-fold lower than a one-step PCR test for PemoNPV, its detection sensitivity was comparable to a dot blot. Due to its simplicity not reliant on sophisticated equipment or specialized skills, the strip test could be adopted to screen easily for PemoNPV infections at shrimp hatcheries and farms. [Copyright &y& Elsevier]

Abstract: An immunochromatographic strip test using gold nanoparticles was developed for the rapid detection of Salmonella typhi (S. typhi) in human serum. The strip test based on the principle of sandwich immunoassay by the specific binding of antigens from S. typhi O901 and antibody of S. typhi O901 on a nitrocellulose membrane. Antibody–gold nanoparticle conjugate was used as the label and was coated onto a glass fiber membrane, which was used as a conjugate pad. To create a test and control zone, antibody of S. typhi O901 and an anti-IgG were dotted on the nitrocellulose membrane, respectively. Positive samples were displayed as red dots at the test and control zones of the nitrocellulose membrane, while negative samples resulted in a red dot only in the control zone. The limit of detection (LOD) was found to be 1.14×105 cfumL−1, which could be visually detected by the naked eye within 15min. This strip test provided a lower detection limit and analysis time than a dot blot immunoassay (8.88×106 cfumL−1 for LOD and 110min for reaction time). In addition, our immunochromatographic strip test was employed to detect S. typhi in human serum effectively, with high accuracy. This strip test offers great promise for a rapid, simple and low-cost analysis of S. typhi. [Copyright &y& Elsevier]

Salbutamol, one of the β-agonists, is misused as a growth promoter in meat producing animals. In-house synthesized colloidal gold was conjugated with the polyclonal anti-salbutamol antibodies. A rapid immunochromatographic assay was developed in a competitive format. The salbutamol-BSA conjugate and goat anti-rabbit IgG were immobilized on a nitrocellulose membrane as test and control lines, respectively. The color intensity of a purple test line was inversely proportional to the amount of salbutamol presenting in the samples. The sensitivity was estimated to be about 80 ng/mL of salbutamol in PBS. The method can be useful as an “on-site” screening procedure for detection of salbutamol. [ABSTRACT FROM AUTHOR]

Abstract: Objective: This study compared the performance of the immunochromatographic strip (ICS) to the Venereal Disease Research Laboratory (VDRL) test and Treponema pallidum haemagglutination assay (TPHA) at a primary health care setting. Methods: The study group was comprised of 150 females randomly drawn from a population of pregnant women attending their first antenatal visit or follow-up visits at West Maternity Hospital in Eldoret Kenya, but without a previous syphilis test during that pregnancy. On-site VDRL, ICS and TPHA tests were performed and immediate treatment provided where appropriate. The performance of the three tests was compared. Results: The sero-prevalence of syphilis as determined by the VDRL test was 3%. There was no significant difference between the ICS and the VDRL test (P > 0.05). The sensitivity and specificity of the ICS test were 80% and 98.6% respectively, while the negative predictive value (NPV) and positive predictive value (PPV) were both 100%. On the other hand, the sensitivity and specificity of the VDRL test were 66.7% and 99.3%, while the NPV and PPV were 80% and 98.6% respectively. The Treponema pallidum haemagglutination assay was used as a reference test and had sensitivity, specificity, NPV and PPV of 100%. Conclusion: The diagnostic accuracy of the ICS compared favorably with the VDRL gold standard. The use of the ICS in Kenya can improve the diagnosis of syphilis in health facilities both with and without laboratories and allow community health care workers to make a rapid diagnosis of the disease, and consequently make immediate therapeutic decisions. [Copyright &y& Elsevier]

Alpha-thalassaemia 1 genetic disorder occurs when there is a deletion of two linked alpha-globin genes. The interaction between these abnormal genes leads to the most severe type of thalassaemia disease, haemoglobin (Hb) Bart's hydrops fetalis. The identification of alpha-thalassaemia 1 carriers and genetic counselling are essential for the prevention and control of severe thalassaemia diseases. In this study, we have developed a rapid screening method for identifying alpha-thalassaemia 1. A sandwich-type immunochromatographic (IC) strip test was developed, using the generated monoclonal anti-Hb Bart's antibody, to trace the Hb Bart's in haemolysates. When assayed by our IC strip test, all alpha-thalassaemia 1, HbH disease, HbH-Constant Spring (H-CS) disease, HbH-CS and heterozygous HbE (CSEA) Bart's disease, and homozygous alpha-thalassaemia 2 showed positive results. No false negative results were observed in these blood samples. In alpha-thalassaemia 2 heterozygotes, 83% of them showed positive reactivity. Among HbE (both homozygotes and heterozygotes), beta-thalassaemia (heterozygotes, homozygotes and beta-thalassaemia/HbE) and normal subjects, the IC strip test revealed negative reactivity of 100, 85 and 97%, respectively. These results indicate that this novel immunodiagnostic kit, in combination with red blood cell indices, is suitable for screening and ruling out mass populations for the presence of alpha-thalassaemia 1. [ABSTRACT FROM AUTHOR]

The aim of this study was to detect the sensitivity and specificity of rapid syphilis diagnostic tests (immunochromatographic strip [ICS] test and rapid test device [RTD]) performed by low-skilled paramedics in field clinics and by highly-skilled technologists in laboratories and compare them with the gold standard (rapid plasma reagin [RPR] and Treponema pallidum haemagglutination [TPHA]) tests for diagnosis of syphilis. A cross-sectional study was conducted among female sex workers (FSWs) in Dhaka, Bangladesh, from August 2004 to July 2005. Blood specimens were tested for syphilis using (i) ICS, (ii) RTD, (iii) RPR tests performed by low-skilled paramedics; and (i) ICS, (ii) RTD, (iii) RPR and (iv) TPHA tests by highly-skilled technologists. The sensitivity and specificity of the ICS and RTD test performed by low- and highly-skilled personnel were compared with the gold standard. A total of 684 FSWs were enrolled and the prevalence of syphilis among FSWs was 20.8% as determined by the gold standard. There was no significant difference in the performance of ICS test done by paramedics in the field when compared with the gold standard performed by highly-skilled technologists in the laboratory (sensitivity, 94.45%; specificity, 92.6%). The ICS test could fulfil the need for a non-invasive, rapid screening test for syphilis. [ABSTRACT FROM AUTHOR]

Abstract: Currently, high-performance liquid chromatographic (HPLC) methods are mainly used to measure antiretroviral plasma concentrations in HIV-infected patients. Although the utility of routine therapeutic drug monitoring (TDM) as an additional tool to optimize long-term antiretroviral therapy is unclear, if TDM is to be widely used, the availability of simple, cheap and reliable methods for the measurement of antiretroviral drug levels are needed, particularly in resource-limited settings. In this study, an immunochromatograhic (IC) strip test to detect the presence of nevirapine (NVP) in body fluids has been developed. Antiserum to NVP was first raised in rabbits by immunization against NVP chemically conjugated with bovine serum albumin, and subsequently validated by Western immunoblotting and competitive indirect ELISA. The partially purified anti-NVP antibodies were conjugated with colloidal gold particles. The conjugation of the colloidal gold and polyclonal antibodies was monitored by UV–vis spectroscopy, while transmission electron microscopy images were used to characterize the particle size and shape of the conjugates. The resulting colloidal gold conjugates were used for the production of an IC strip test to detect nevirapine in human plasma. Preliminary assessment suggests no-cross reactivity of the NVP polyclonal antibodies but assessment of plasma samples from HIV-infected patients receiving HAART needs to be conducted. This assay could potentially be used for drug monitoring as part of the clinical care of HIV infected patients. [Copyright &y& Elsevier]

The Lateral Flow Immunoassay (LFIA) is by far one of the most successful analytical platforms to perform the on-site detection of target substances. LFIA can be considered as a sort of lab-in-a-hand and, together with other point-of-need tests, has represented a paradigm shift from sample-to-lab to lab-to-sample aiming to improve decision making and turnaround time. The features of LFIAs made them a very attractive tool in clinical diagnostic where they can improve patient care by enabling more prompt diagnosis and treatment decisions. The rapidity, simplicity, relative cost-effectiveness, and the possibility to be used by nonskilled personnel contributed to the wide acceptance of LFIAs. As a consequence, from the detection of molecules, organisms, and (bio)markers for clinical purposes, the LFIA application has been rapidly extended to other fields, including food and feed safety, veterinary medicine, environmental control, and many others. This review aims to provide readers with a 10-years overview of applications, outlining the trends for the main application fields and the relative compounded annual growth rates. Moreover, future perspectives and challenges are discussed. [ABSTRACT FROM AUTHOR]

Plum pox, or Sharka disease, caused by infection with plum pox virus (PPV), results in enormous economic losses to the stone fruit industry. However, the frequency and distribution of PPV remain unclear in China, the world's largest stone fruit producer. Systemic visual surveys were performed on stone fruit trees in China from 2008 to 2018, and the results suggest that plum pox disease is widely distributed on common apricots ( Prunus armeniaca ) and Japanese apricots ( Prunus mume ), with an average symptoms incidence rate >30% in the latter. In samples collected from Beijing, Nanjing, Shanghai, Wuhan, Wuxi, and Yuncheng, PPV was detected in 77% (85 of 110) of collected samples by immunochromatographic (IC) strip tests and reverse transcription PCR, and 96% (67 of 70) of samples showing Sharka symptoms were PPV positive. Transmission electron microscopy revealed filamentous particles of ∼640 × 12.5 nm ( n = 19) in size and pinwheel inclusions in symptomatic plants but not in the asymptomatic and PPV-negative plants. Full-length genomes were determined for four isolates (three from Japanese apricot and one from common apricot), and phylogenetic analyses indicated that all four isolates belong to a clade PPV-D, despite slight differences in genome size. These findings not only highlight the widespread occurrence and distribution of PPV in China but also provide detailed information about the genomic characteristics and evolutionary position of PPV isolates in China.

Adult-onset immunodeficiency syndrome (AOID) patients with autoantibodies (autoAbs) against interferon-gamma (IFN-γ) generally suffer from recurrent and recalcitrant disseminated non-tuberculous mycobacterial diseases. Since the early stages of AOID do not present specific symptoms, diagnosis and treatment of the condition are not practical. A simplified diagnostic method for differentiating AOID from other immunodeficiencies, such as HIV infection, was created. Anti-IFN-γ is generally identified using enzyme-linked immunosorbent assay (ELISA), which involves an instrument and a cumbersome process. Recombinant IFN-γ indirectly conjugated to colloidal gold was used in the modified immunochromatographic (IC) strips. The biotinylated-IFN-γ was incorporated with colloidal-gold-labeled 6HIS-maltose binding protein-monomeric streptavidin (6HISMBP-mSA) and absorbed at the conjugate pad. The efficacy of the IC strip upon applying an anti-IFN-γ autoAb cut-off ELISA titer of 2500, the sensitivity and specificity were 84% and 90.24%, respectively. When a cut-off ELISA titer of 500 was applied, the sensitivity and specificity were 73.52% and 100%, respectively. [ABSTRACT FROM AUTHOR]

• A lanthanide-labeled immunochromatographic strip test for pathogen is reported. • Immunomagnetic separation is combined as pretreatment to increase sensitivity. • Our custom-designed portable reader provides rapid quantitative determination. • The detection limit is 103 CFU/mL in milk and human serum with good specificity. • Detection process is rapid (< 1.5 h) and easy to use in food and clinical fields. Sensitive point-of-care pathogen detection methods are urgently required as pathogens pose a significant threat to food safety and human health. Here, we reported a platform based on a lanthanide-labeled immunochromatographic strip test combined with immunomagnetic separation for the detection of pathogens in food and clinical samples. First, immunomagnetic separation technology was employed as a pre-treatment to eliminate the effect of background in the samples. Then, the lanthanide chelate-loaded carboxyl-modified polystyrene nanoparticles, exhibiting bright luminescence, wide Stokes shift, and excellent stability, were prepared and used to label pathogens with antibody. Finally, an immunochromatographic strip test, based on a sandwich format and supported by our custom-designed portable reader, was used to rapidly quantify the result. Using Salmonella typhimurium as a model pathogen, under optimal conditions, we achieved a detection limit of 103 CFU/mL and a linear range of 104–106 CFU/mL in milk and human serum with good recovery, reproducibility, and specificity. Compared with the existing colloidal gold-based immunochromatographic strip test, our platform showed high sensitivity (100-fold improvement) and provided quantitative determination. Our detection platform was therefore demonstrated to be highly sensitive, rapid (within 1.5 h), and cost-effective, providing a promising platform for point-of-care pathogen detection in food and clinical fields. [ABSTRACT FROM AUTHOR]

A rapid test for detecting total immunoglobulins directed towards the nucleocapsid protein (N) of severe acute syndrome coronavirus 2 (SARS CoV-2) was developed, based on a multi-target lateral flow immunoassay comprising two test lines. Both test lines bound to several classes of immunoglobulins (G, M, and A). Specific anti-SARS immunoglobulins were revealed by a colorimetric probe formed by N and gold nanoparticles. Targeting the total antibodies response to infection enabled achieving 100% diagnostic specificity (95.75–100, C.I. 95%, n = 85 healthy and with other infections individuals) and 94.6% sensitivity (84.9–98.9, C.I. 95%, n = 62 SARS CoV-2 infected subjects) as early as 7 days post confirmation of positivity. Agreeing results with a reference serological ELISA were achieved, except for the earlier detection capability of the rapid test. Follow up of the three seroconverting patients endorsed the hypothesis of the random rise of the different immunoglobulins and strengthened the 'total antibodies' approach for the trustworthy detection of serological response to SARS CoV-2 infection. Image 1 A rapid test based on the lateral flow immunoassay technology was established to detect the total serological response to the SARS CoV-2 infection. • A sensitive and specific lateral flow immunoassay for detecting antibodies to Covid-19. • Broad-specific agents to capture total immunoglobulins enabled increasing the sensitivity. • Two test lines were combined to guarantee no false positive results. • Diagnosis based on the multi-target LFIA can complement molecular assays. [ABSTRACT FROM AUTHOR]

• Reliable detection of urinary PSA was performed in 10 minutes through a new intuitive lateral flow biosensor. • The lateral flow biosensor showed a limit of detection and a range of quantification of 20 ng mL-1 and 37 – 420 ng mL-1, respectively. • The biosensor showed 92% of accuracy and an almost perfect concordance with the reference ECLIA method. • The biosensors showed acceptable precision with CV % ≤ 13% and diagnostic sensitivity, specificity, positive predictive value and negative predictive value of 100%, 64%, 74% and 100%, respectively. • The uPSA biosensor is a convenient tool to guide clinical decision-making in prostate cancer diagnosis management process. This work describes the development and the application of a lateral flow biosensor for the detection of the prostate specific antigen in urine (uPSA). The biosensor allowed uPSA detection in 10 minutes with a limit of detection and a range of quantification respectively of 20 ng mL-1 and 37 – 420 ng mL-1, showing within and between-day coefficients of variation ≤ 13%. It showed 92% of accuracy and an almost perfect concordance with the reference electrochemiluminescence immunoassay method. The biosensor design provides the disappearance of the Test line signal at the cut-off concentration. This was achieved with a double layer sensing strategy, in which gold nanoparticles were functionalized with Staphylococcal protein A – a mediator – instead of anti-PSA antibody. This strategy allow making a fine-tune on the concentration of the specific antibody, obtaining an on/off switch of the Test line at the cut-off value. The cut-off value was also established in this work, based on the distribution of uPSA levels from 140 patients, who were suspected of prostate cancer and who underwent to first biopsy. The clinical application of the biosensor to predict repeat biopsy outcome in 28 patients showed sensitivity, specificity, positive and negative predictive values of 100%, 64%, 74% and 100%, respectively. [ABSTRACT FROM AUTHOR]

• A rapid immunochromatographic strip test was developed for LMG detection. • The qualitative sensitivity for LMG detection was 2 µg/L. • The quantitative LOD was 0.28 µg/L. • The developed immunochromatographic strip test can be performed use easily with short analysis time. A rapid and simple immunochromatographic strip test assay based on competitive format was developed for leucomalachite green (LMG) detection. LMG-bovine serum albumin and rabbit anti-sheep IgG were immobilized on nitrocellulose membrane for the test line and control line, respectively. Anti-LMG-colloidal gold conjugate was immobilized onto the conjugate pad. For qualitative detection, the cut-off limit of the strip test was determined at 2 µg/L by the naked eye. For quantitative analysis, the working range of the LMG detection was 0.7–2 µg/L with LOD at 0.28 µg/L. A one-step immunochromatographic strip test for LMG detection can be completed within 5 min without any incubation, washing and blocking steps. Analysis results of LMG in aquatic animals obtained from the immunochromatographic strip test were in good agreement with those realized from enzyme-link immunosorbent assay. The developed the immunochromatographic strip test offered rapid detection as a simple (one-step), cost-effective, instrument-free assay and no need for handling reagents. [ABSTRACT FROM AUTHOR]

A rapid, portable, and semi-quantitative immunochromatographic strip was developed for rapid and visual detection of alternariol monomethyl ether (AME). For this purpose, the anti-AME monoclonal antibody (mAb) was prepared and identified. AME coupled to bovine serum albumin (BSA) via methyl 4-bromobutanoate was prepared as immunogen. The recoveries of AME in spiked cherry and orange fruits determined by competitive ELISA were 86.1% and 80.7%, respectively. A colloidal gold nanoparticle (CGN) and CGNs-mAb conjugate were synthesized, and on this basis, a competitive colloidal gold immunochromatographic strip was developed and applied to the detection of AME toxin in fruit samples. The intensity of red density of the test line (T line) is inversely proportional to AME concentration in the range 0.1-10 ng/mL. The visual limit of detection (LOD) of AME was found to be about 10 ng/mL. The semi-quantitative detection can be completed in 10 min. Moreover, the immunochromatographic strip has lower cross-reactivity with AME analogues, and it has a good stability performance (following 3 months of storage). Hence, the colloidal gold immunochromatographic strip could be used as a semi-quantitative tool for the on-site, rapid, and visual detection of AME in fruit.