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Enrofloxacin, a veterinary antibiotic that persists in food, poses a risk to human health. Here, a monoclonal antibody against enrofloxacin, 1H12, was prepared based on the hapten ENR-1, and showed excellent sensitivity with a 50% inhibitory concentration (IC 50) of 0.03 ng/mL. Using this antibody, 2 lateral-flow immunochromatographic assays were developed for determination of enrofloxacin in egg, milk, honey, and chicken meat samples. The detection ranges (IC 20 –IC 80) were 0.16–0.82 ng/g, 0.24–1.8 ng/g, 0.25–3.6 ng/g, and 0.61–3.9 ng/g by colloidal gold-immunochromatographic sensor (CG-ICS) analysis, and 0.022–0.42 ng/g, 0.054–0.42 ng/g, 0.069–1.4 ng/g, and 0.19–2.2 ng/g by Eu-fluorescence-immunochromatographic sensor (EF-ICS) analysis. The intraassay and interassay recovery rates were 88.9 to 108.5% with coefficients of variation of 1.3 to 7.0% by CG-ICS analysis, and 88.6 to 113.6% with coefficients of variation of 1.3 to 8.1% by EF-ICS analysis. Thus, our newly developed ICS are sensitive and reliable, providing an option for rapid quantitative detection of enrofloxacin in food samples. [ABSTRACT FROM AUTHOR]

A fluorescent immunochromatographic test (FM-ICT) was developed for rapid detection of anti- Orientia tsutsugamushi antibodies in serum samples. The FM-ICT was constructed based on the dual-antigen sandwich method. Truncated 56 kDa outer membrane protein of O. tsutsugamushi strain SJ, was expressed in E. coli and mixed with those of Ptan and Gillam strains. A thin line of the protein mixture was precisely sprayed across a nitrocellulose membrane making this the "Test" line. Polyclonal antibodies (pAbs) to O.tsutsugamushi were sprayed in another line across the membrane making this the "Control" line. Fluorescent microspheres conjugated 56 kDa proteins reacting with sample serum will be captured on the "Test" line if the sample contains antibodies to O.tsutsugamushi. Several experimental parameters were optimized. After optimizing the reaction procedure, the results are visible, within 6 min, with the naked eye under ultraviolet light. The limit of detection (LOD) was determined to be 7.63 ng/mL with prepared polyclonal antibodies. No cross-reaction was observed with sera samples from other febrile diseases. In clinical evaluations, the strips showed 94.92% sensitivity (106/112) and 93.75% specificity (56/60). The FM-ICT we developed will provide a new tool for on-site diagnosis of scrub typhus. • Recombinant proteins of three epidemic strains were mixed as diagnostic antigen. • Fuorescent microsphere were used in immunochromatographic strip for lower LOD. • Results can be read by naked eyes with the help of a portable UV lamp. • Suitable for on-site diagnosis in lab, families, even in the wild or remote areas. [ABSTRACT FROM AUTHOR]

Peste des petits ruminants virus (PPRV) causes a very devastating disease in sheep and goats. Rapid diagnosis and immunisation have been identified as key strategies for successful prevention of the disease. Therefore, a sensitive fluorescent microsphere immunochromatography test strips (FM-ICTS) was developed for rapid detection of special antibodies of PPRV in goats and sheep serum. The FM-ICTS were successfully prepared by fluorescent microspheres (FM) as tracer, which were covalently coupled to PPRV nucleocapsid protein (NP). The NP and monoclonal antibody of NP 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 (T/C) is 0.050. The repeatability of the FM-ICTS was excellent, with an overall average CV of 3.17 %. The detection limit of this assay was 1:5120. Additionally, the FM-ICTS no cross reaction with the sera of other related diseases was observed, only reacting with anti-PPRV serum. 70 serum samples were tested by FM-ICTS and commercial ELISA kit, and the results showed good agreement. Overall, a promising pen-side diagnostic tool was developed for the rapid qualitatively/semi-quantitatively detection of PPRV antibodies within 15 min. • We developed an FM-ICTS approach that can identify antibodies against PPRV. • The FM-ICTS is capable of detecting various types of antibodies in serum, including IgG and IgM. • The FM-ICTS assay can be used as a tool to assess the effects of vaccine immunization after vaccination. [ABSTRACT FROM AUTHOR]

A quantitative immunochromatographic assay (QIA) was developed by using gold nanoparticle (GNP)-based lateral flow strip biosensor (LFSB) and a portable strip reader for rapid and sensitive quantitation of Carbohydrate Antigen 19-9 (CA 19-9) in human plasma. CA 19-9 is a biomarker that has been associated with cancers (such as pancreatic and colorectal cancers) and various non-cancerous diseases. The principle is based on sandwich-type immunoreactions between gold nanoparticle (GNP)-labelled detection antibody, anti-CA 19-9 capture antibody and CA 19-9to capture the GNPs on the test zone of LFSB. The accumulation of GNPs on the test zone gave a red line whose intensity was read with a portable strip reader to quantify the concentration of CA 19-9. Assay parameters including the membrane type, antibody concentration, amount of GNP-anti-CA 19-9 conjugates and the components of the running buffer were optimized to obtain the best sensitivity and reproducibility of the assay. The detection limit of the assay was determined to be 5 U mL −1 (S/N = 3) with a linear range of 5 U mL −1 –100 U mL −1 . CA 19-9 concentrations in healthy human and pancreatic cancer patient plasma samples were successfully evaluated using the developed quantitative immunochromatographic assay (QIA), and the results were in accordance with that obtained with enzyme linked immunosorbent assay (ELISA). The developed assay shows great promise for clinical application and biomedical diagnosis, particularly in limited resource settings. [ABSTRACT FROM AUTHOR]

Highlights • The cT of wild-type rotavirus is lower than Rotarix (median 12.43 verses 29.09). • The limit of detection of the Combi-Strip (Coris, BioConcept) is about Ct 18. • Real-time RT-PCR is more sensitive than an immunochromatographic method. Abstract Background Diagnosis of wild-type rotavirus disease may be complicated by the detection of vaccine-derived virus which can be detected in stool samples following immunisation. We evaluate an immunochromatographic assay and real-time RT-PCR to determine which is more suitable for the detection of wild-type rotavirus. Objectives To compare the Ct values of wild-type rotavirus and Rotarix determined by real-time RT-PCR. To establish the Ct value corresponding to the limit of detection of the immunochromatographic Combi-Strip method (Coris, BioConcept). Study design Retrospective review of real-time RT-PCR Ct values was performed on 100 samples tested by a pan-rotavirus assay (n = 50 wild-type, n = 50 Rotarix). Secondly the limit of detection of the Combi-Strip assay was determined by testing; wild-type rotavirus (n = 33, Ct range 6.85–34.26) samples, Rotarix (n = 9, Ct range 20.86–34.26) samples and rotavirus negative (n = 21) samples. Results The median Ct of 50 wild-type rotavirus was Ct 12.43; range 6.11–32.66 compared with the median of 50 Rotarix, Ct 29.09; range 18.91–35.28, p=<0.0001. The limit of detection of the Combi-Strip method was approximately Ct 18. The 21 rotavirus negative samples were negative by real-time RT-PCR and Combi-Strip. Conclusions We found the Ct value was significantly lower, and therefore the viral load higher, for wild-type rotavirus compared to detectable Rotarix. The Combi-Strip assay detects most wild-type infections; however, it lacks sensitivity to detect low-level wild-type rotavirus and, beneficially, is unlikely to detect Rotarix. It is not a more suitable method than real-time RT-PCR when a definitive rotavirus result is required. [ABSTRACT FROM AUTHOR]

Abstract: Aims: Chinese herbal products for weight loss are popular purchases by women in Iran. They are also available around the world via the internet. The content of some of these popularly purchased products was investigated for the presence of illegal substances and thyroid hormones. Materials and methods: Nine different types of herbal weight loss tablets were obtained from the retail marketplace and subjected to qualitative chemical analysis. Immunochromatographic assays for detection of phencyclidine and radioimmunoassay methods for thyroid hormones (T3 and T4) were employed. Results: All products except three contained triiodothyronine (T3), Magic Slim and 100% Original Super Slim also contained thyroxine (T4), 0.13μmol and 0.81μmol per capsule respectively. Phencyclidine (PCP) was found in Herbarceous Essence, Green Lean Super Slim and Fat Loss. Conclusion: The Chinese herbal slimming products analyzed contained thyroid hormones and PCP without labeling their contents. Accurate labeling and good surveillance systems are required to ensure the protection of consumers. [Copyright &y& Elsevier]

Abstract: We prospectively evaluated the Bio-Rad nonstructural 1 (NS1) enzyme-linked immunosorbent assay (ELISA) and lateral flow immunochromatographic assay (LFIA) in comparison to an in-place reverse transcription–polymerase chain reaction for dengue diagnosis. Among 537 consecutive samples from patients with acute febrile disease, 264 (49.2%) tested positive in reverse transcription–polymerase chain reaction (RT-PCR), 156 (29.1%) in NS1-antigen (Ag) ELISA, and 125 (23.3%) in NS1-Ag LFIA. Compared to the RT-PCR status, the specificity was 100% for the NS1-Ag ELISA and LFIA, but their respective sensitivities were 61.2% [95% confidence interval (CI), 55.2−67.2] and 49.4% (95% CI, 43.2−55.6), with nadirs of 37.9% and 24.1% on day 6 of illness. The NS1-Ag ELISA and LFIA were positive, respectively, for 48.0% and 40.7% of the secondary infections versus 85.0% and 66.7% of the primary infections. For patients <5 years old, NS1-Ag ELISA and LFIA reached respective sensitivities of 100% and 90.5%. Reports of results of dengue NS1-Ag assays should specify that negativity does not preclude DENV infection, and require further investigations in the case of severe disease. [ABSTRACT FROM AUTHOR]

Abstract: Background: The detection of norovirus by ELISA and immunochromatographic methods may facilitate epidemiological studies into the global disease burden associated with norovirus gastroenteritis and provide a quick method of testing for norovirus infection. Objectives: To evaluate the new RIDASCREEN norovirus ELISA (3rd generation) and RIDAQUICK norovirus immunochromatographic test on a collection of samples from Brazilian children with acute gastroenteritis, and compare them against the established 2nd generation IDEIA norovirus assay. Study design: Reverse transcriptase PCR, the study reference standard, was used to test 726 specimens for the presence of norovirus. All 96 norovirus positive samples and a systematic selection of negative samples were tested by RIDASCREEN, RIDAQUICK and IDEIA norovirus tests. Results: The sensitivity of RIDASCREEN for the detection of norovirus was 63% (95% CI: 53–72%) and RIDAQUICK 69% (95% CI: 58–78%); both were >98% specific. The IDEIA had a sensitivity of 45% (95% CI: 35–55%), significantly lower than RIDASCREEN and RIDAQUICK (p ≤0.01). The sensitivity of RIDASCREEN and RIDAQUICK in detecting GII.4 noroviruses, the principal norovirus strain identified in community and nosocomial infection globally, was 78% and 88% respectively. Conclusion: The norovirus RIDASCREEN test may be useful in epidemiological studies of norovirus infection and the norovirus RIDAQUICK test offers an accurate and rapid method of detecting norovirus infection. [ABSTRACT FROM AUTHOR]

[Display omitted] • Based on competitive immunoassay and SERS a rapid and highly sensitive method for the detection of bisphenol A in water was established. • The detection limitation was 0.1pg/mL. • This method shows broad prospects for applications in the fields of biomedical diagnosis and food safety monitoring. Sensitive and selective detection of target analyte is very important in many fields such as commodity inspection and quality monitoring. In this work, based on the principle of competitive immunoassay, surface-enhanced Raman spectroscopy (SERS) was used to establish a rapid and highly sensitive method for the detection of trace amounts of bisphenol A in water. Here, Raman molecule 5,5-dithiobis-2-nitrobenzoic acid and anti-BPA antibody were conjugated with Au (core)@Ag (shell) nanoparticle to serve as SERS nanoprobe. After the SERS nanoprobe is combined with the substance to be tested, it uses the siphon effect to pass through the test line and the charging line on the test strip. And the Raman test was performed on the T line with a Raman spectrometer. The detection limitation was 0.1 pg/mL. Compared with the reported gas chromatography, liquid chromatography, fluorescence analysis, and other detection methods, SERS ICA does not demand complicated sample preparation procedures, and has the advantages of simple detection methods, quick results, High sensitivity, good specificity, and low technical demands for laboratory environment and testers. In addition, Raman spectrometers have gradually developed to be portable, making it easier to meet the needs of on-site rapid and highly sensitive detection, and will show broad prospects for applications in the fields of biomedical diagnosis and food safety monitoring. [ABSTRACT FROM AUTHOR]

Abstract: A one-step immunochromatographic assay (ICA) was developed for the detection of seven kinds of cephems in milk. Polyclonal antibodies (PcAb) with group-specific to cephems were raised in rabbits after immunization with cephalexin–keyhole limpet hemocyanin (KLH) conjugate. The specificity of anti-sera was determined by indirect competitive enzyme-linked immunosorbent assay (icELISA), and the 50% inhibitions (IC50) of cephalexin and cefadroxil were obtained at 1.5ngmL−1; IC50 of cefatiofur, cefapirin, cefazolin, cefalothin and cefotaxine were 4, 3.7, 3.2, 4.5 and 5ngmL−1, respectively. The PcAb against cephems were conjugated to colloidal gold particles as the detection reagent for ICA strips to test for cephems. This method achieved semi-quantitative detection of cephems in <5min, with high sensitivity to cephalexin and cefadroxil (both 0.5ngmL−1). At the same time, cefatiofur, cefapirin, cefazolin, cefalothin and cefotaxine were detected at <100ngmL−1 in spiked processed-milk samples. This method was compared with an enzyme-linked immunosorbent assay by testing 40 milk samples, and the positive samples were validated by a high-performance liquid chromatographic method, with an agreement rate of 100% for both comparisons. In conclusion, the method was rapid and accurate for the multi-residue detection of cephems in milk. [Copyright &y& Elsevier]

Abstract: We describe a multiplex electrochemical immunoassay based on the use of gold nanoparticle (Au-NP) probes and immunochromatographic strips (ISs). The approach takes advantage of the speed and low cost of the conventional IS tests and the high sensitivities of the nanoparticle-based electrochemical immunoassays. Rabbit IgG (R-IgG) and human IgM (H-IgM) were used as model targets for the demonstration of the proof of concept. The Au-NPs based sandwich immunoreactions were performed on the IS, and the captured gold nanoparticle labels on the test zones were determined by highly sensitive stripping voltammetric measurement of the dissolved gold ions (III) with a carbon paste electrode. The detection limits are 1.0 and 1.5ngml−1 with the linear range of 2.5–250ngml−1 for quantitative detection of R-IgG and H-IgM, respectively. The total assay time is around 25min. Such multiplex electrochemical immunoassay could be readily highly multiplexed to allow simultaneous parallel detection of numerous proteins and is expected to open new opportunities for protein diagnostics and biosecurity. [Copyright &y& Elsevier]

Abstract: We evaluated 2 commercial enzyme-linked immunosorbent assays (ELISAs) for the diagnosis of dengue infection; one a serologic test for immunoglobulin M (IgM) antibodies, the other based on detection of dengue virus nonstructural 1 (NS1) antigen. Using gold standard reference serology on paired sera, 41% (38/92 patients) were dengue confirmed, with 4 (11%) acute primary and 33 (87%) acute secondary infections (1 was of indeterminate status). Sensitivity of the NS1-ELISA was 63% (95% confidence interval [CI], 53–73) on admission samples but was much less sensitive (5%; 95% CI, 1–10) on convalescent samples. The IgM capture ELISA had a lower but statistically equivalent sensitivity compared with the NS1-ELISA for admission samples (45%; 95% CI, 35–55) but was more sensitive on convalescent samples (58%; 95% CI, 48–68). The results of the NS1 and IgM capture ELISAs were combined using a logical OR operator, increasing the sensitivity for admission samples (79%; 95% CI, 71–87), convalescent samples (63%; 95% CI, 53–73), and all samples (71%; 95% CI, 65–78). [Copyright &y& Elsevier]

Summary: A New Zealander travelling recreationally to Asia became exposed to Bancroftian filariasis. The traveller had presented incidentally with gastrointestinal illness. In addition to diarrhoea, the traveller''s symptoms were non-specific and there was no eosinophilia, lymphoedema, lymphangitis, lymphadenitis, or pain. The immunochromatographic test for Wuchereria bancrofti was positive indicating that there was or had been an adult filarial worm. The illness resolved completely following treatment with ivermectin. [Copyright &y& Elsevier]

Abstract: A rapid, signal step and sensitive immunochromatographic (IC) test for detection of aflatoxin B1 (AFB) in foods was described. Colloidal gold-labeled polyclonal antibody specific to AFB was used as the marker; AFB–BSA conjugate was the competitive antigen and goat-anti-rabbit antibody as control. Conditions for the analysis of AFB to be completed in less than 10min were optimized. With visual observation, the lower limit was found to be around 2.5ppb. For quantitative analysis by adopting a photometric strip reader, the lower detection limit was found to be around 0.05–0.1ppb. The detection limit for AFB in food extract was around 2μg/kg (ppb). The analytical recoveries for AFB added to extracts of rice, corn, and wheat and spiked directly to these foods range in 2–50ppb were found to be 80.79% (CV, 10.92%) to 110.56% (CV, 7.95%). The CVs of all the assays were between 6.27% and 14.63%. Sixty seven naturally contaminated food samples were subjected to both IC strip and commercial ELISA kit test for AFB. Results showed a good correlation between these two methods with a square of correlation coefficient of 0.93 and slop of 1.13. [Copyright &y& Elsevier]

• A smartphone based enzyme-linked immunochromatographic sensor (ELICS) system was developed. • ELICS had an ambient light sensor and small reading device for quantitative detection of target molecules. • ELICS was easy performing and more sensitive than conventional immunochromatographic assay. • ELICS could be used for on-site detection such as carcinoembryonic antigen (CEA) in clinicals. The development and application of portable, cost-effective, and user-friendly biosensing technology to enable real-time disease diagnosis on the spot are alway a top priority in the in vitro diagnostic (IVD). Here, a smartphone based enzyme-linked immunochromatographic sensor (ELICS) system was developed as required. This hand-held sensing system utilizes built-in ambient light sensor in smartphone and integrated with a specially designed disposable chromatography device. Immunoassay and enzyme coloration are performed on the chromatography device to form a biosensor channel, and the results are read directly by the smartphone ambient light sensor. To demonstrate this platform, the commonly used cancer biomarker carcinoembryonic antigen (CEA) was chosen as a proof-of-concept test. This method was 100-folds more sensitive than conventional used immunochromatographic assay, and whole detection and analysis process was completed within 25 min. For detection of CEA in clinical serum samples, the ELICS results were well correlated with those from chemiluminescence immunoassay (CLIA). With the advantages of high sensitivity, rapid, user-friendly, low cost and portability, ELICS would have wide applicability in family and community medical institution, especially in the areas of poor medical resources. [ABSTRACT FROM AUTHOR]