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Paclitaxel (PTX), methotrexate (MTX), and 5-fluorouracil (5-FU) are commonly-used small molecule anti-tumor drugs for breast cancer. Unfortunately, drug resistance occurs with long-term treatment or excessive use, and the high concentrations of PTX, MTX, and 5-FU in patients may lead to side effects with dose-limiting toxicities, such as myelosuppression, hepatotoxicity, and peripheral neuropathy. Therefore, concentration monitoring of PTX, MTX, and 5-FU in clinical treatment is very important. We prepared highly sensitive and specific monoclonal antibodies using several haptens, and established a multiple paper-based sensor utilizing optical signals of gold nanoparticles, which simultaneously detected PTX, MTX, and 5-FU in human plasma or urine with 10 min. A portable scanner for quantitative detection in plasma and urine samples was used, and the calculated limit of detection (cLOD) values were 0.002 and 0.142 µg/mL for PTX, 0.187 and 0.976 ng/mL for MTX, and 0.057 and 0.128 µg/mL for 5-FU, respectively. In the recovery test, the recovery rates and the coefficient of variation were 85.84%–108.81% and 1.23%–8.80%, respectively, indicating the reliability and accuracy of the multiple gold immunochromatographic strip (GIS). In addition, for the determination of collected clinical plasma samples, the correlation between the test data of the multiple GIS and liquid chromatography–tandem mass spectrometry (LC–MS/MS) was good. Therefore, the developed multiple GIS could be applied to the rapid detection of PTX, MTX, and 5-FU in different clinical samples. [ABSTRACT FROM AUTHOR]

Human epidermal growth factor receptor 2 (HER2) is an important biomarker for detection and treatment of breast cancer. In this study, we developed monoclonal antibodies against the extracellular domain (ECD) of HER2 and established a rapid and accurate lateral flow immunoassay (LFIA) for use in community medical institutions. The gene sequence of human HER2-ECD was obtained from the National Center for Biotechnology Information (NCBI) to construct the expression plasmid. HER2-ECD protein expressed in HEK293F cells was used to immunize BALB/c mice. The monoclonal antibodies were produced in mouse ascites and isolated by hybridoma cell screening. Antibodies were analyzed for purity by SDS-PAGE (sodium dodecyl sulphate-polyacrylamide gel-electrophoresis) and affinity was assessed by enzyme-linked immunosorbent assay (ELISA) while subtypes were detected using the commercial kits. The HER2-ECD test strip was prepared based on the sandwich method and evaluated using a portable detection instrument. The affinity of the paired antibodies, 4D8 and 8D9, both reached 1 × 108 L/mol. Both antibodies specifically recognized the HER2-ECD protein in serum. The limit of detection (LOD) of the gold nanoparticle (AuNP)-based LFIA was 1.7 ng/mL with a detection range of 1.7–400 ng/mL, and the performance of the HER2-ECD strip correlated well with that of a Siemens chemiluminescent immunoassay (CLIA) kit. In conclusion, the paired antibodies were successfully prepared with high affinity and specificity. The AuNP-based LFIA of HER2-ECD provides a fast and accurate method to detect the concentration of HER2-ECD in serum samples for clinical use in community medical institutions, and could contribute to determining the progress of the disease or the effectiveness of treatment. [ABSTRACT FROM AUTHOR]

Norovirus is one of the main pathogens causing acute gastroenteritis worldwide, and possesses rich genetic diversity. We established a simple, fast, and suitable colloidal gold immunochromatographic detection method for common epidemic strains of Norovirus. A pair of monoclonal antibodies that are sensitive to recognizing Norovirus was successfully screened and used as gold-labeled antibody and capture antibody, respectively. The assembly conditions of the test strip were optimized to determine the labeling pH, the concentration of capture antibody and concentration of AuNP-labeled antibody, then the performance of the strips, including sensitivity testing and specificity testing, was evaluated. The minimum detection concentration of the established Norovirus colloidal gold test strip detection method is 10 ng mL−1. This antibody has no cross-reactivity with HCoV-NL63, HCoV-OC43, Influenza A (H1N1), Influenza A (H9N2), respiratory syncytial virus or Varicella zoster virus. The established colloidal gold detection method was used to analyze 11 fecal samples, and the results showed that only two samples were positive and the rest were negative, in agreement with the RT-PCR result. The whole colloidal gold test strip detection method process took 15 min, and could be used for on-site detection. The established colloidal gold test strip detection method has good specificity and stability, and can be used for the detection of common Norovirus strains and in large-scale epidemiological investigations. [ABSTRACT FROM AUTHOR]

Dibutyl phthalate (DBP) is widely used as a plasticizer in the production of polymeric materials to give them flexibility, strength and extensibility. However, due to its negative impact on human health, in particular reproductive functions and fetal development, the content of DBP must be controlled in food and the environment. The present study aims to develop a sensitive, fast and simple fluorescence polarization immunoassay (FPIA) using monoclonal antibodies derived against DBP (MAb-DBP) for its detection in open waters. New conjugates of DBP with various fluorescein derivatives were obtained and characterized: 5-aminomethylfluorescein (AMF) and dichlorotriazinylaminofluorescein (DTAF). The advantages of using the DBP-AMF conjugate in the FPIA method are shown, the kinetics of binding of this chemical with antibodies are studied, the analysis is optimized, and the concentration of monoclonal antibodies is selected for sensitivity analysis—16 nM. The calibration dependence of the fluorescence polarization signal for the detection of DBP was obtained. The observed IC50 (DBP concentration at which a 50% decrease in the fluorescence polarization signal occurs, 40 ng/mL) and the limit of detection (LOD, 7.5 ng/mL) values were improved by a factor of 45 over the previously described FPIA using polyclonal antibodies. This technique was tested by the recovery method, and the high percentage of DBP discovery in water ranged from 85 to 110%. Using the developed method, real water samples from Lake Onega were tested, and a good correlation was shown between the results of the determination of DBP by the FPIA method and GC-MS. Thus, the FPIA method developed in this work can be used to determine DBP in open-water reservoirs. [ABSTRACT FROM AUTHOR]

Valproic acid (VPA) is mainly used in the clinic to treat epilepsy, for which the therapeutic window is narrow to avoid causing adverse reactions such as hepatotoxicity and teratogenicity. Therefore, timely therapeutic drug monitoring is needed. A hapten containing a benzene ring and an amino group was designed and used to screen a monoclonal antibody (mAb) 3G10 with high specificity and sensitivity. The IC50 value of mAb 3G10 was ascertained as 68.13 ng mL−1 through an indirect competitive enzyme-linked immunosorbent assay. A colloidal gold-based immunochromatographic strip (CG-ICS) for the detection of free VPA in human serum was developed with gold-labeled mAb 3G10. Qualitative analysis of human serum samples can be conducted through visual observation. The visual limit of detection (vLOD) was 2 μg mL−1, and the cut-off value was 100 μg mL−1. A standard curve for quantitative detection was generated using a portable scanner, with a calculated LOD (cLOD) value of 0.144 μg mL−1 and a linear range of 0.565–48.385 μg mL−1. Comparing the results of CG-ICS for actual positive samples with those of a direct chemiluminescence kit, there was a good correlation between the two methods. Therefore, our CG-ICS can be applied to the rapid clinical monitoring of free VPA. [ABSTRACT FROM AUTHOR]

In this study, we synthesized two haptens similar in structure to nitrofen (NIT), and screened out five monoclonal antibodies with the ability to recognize NIT and bifenox (BIF) by competitive ELISA, with the lowest IC50 values of 0.87 ng mL−1 and 0.86 ng mL−1, respectively. The antibody 5G7 was selected to be combined with colloidal gold to establish a lateral flow immunochromatographic assay strip. This method was shown to qualitatively and quantitatively detect the residues of NIT and BIF in fruit samples. The visual limits of detection for qualitative detection were 5 μg kg−1 and 10 μg kg−1 for NIT and BIF, respectively. The calculated limits of detection for quantitative detection were 0.75 μg kg−1, 1.77 μg kg−1 and 2.55 μg kg−1 respectively, for nitrofen in orange, apple and grapes, and 3.54 μg kg−1, 4.96 μg kg−1 and 5.26 μg kg−1, respectively, for bifenox. Thus the strip assay could be used for rapid analysis of fruit samples. [ABSTRACT FROM AUTHOR]

Cannabidiol (CBD), the most predominant cannabinoid, may cause addiction and liver damage. In this study, we synthesized a CBD hapten containing the carboxyl group of the spacer arm by derivatizing CBD. A highly specific and sensitive monoclonal antibody (mAb) was prepared with a half-maximal inhibitory concentration of 2.03 ng mL−1 and a limit of detection of 0.32 ng mL−1. MAb was highly specific for CBD. We developed an immunochromatographic assay (ICA) for the detection of CBD in functional beverages with a visible limit of detection of 100 ng mL−1 and a cut-off of 1000 ng mL−1. Compared with HPLC, ICA is more efficient and accurate and can be used for the rapid on-site detection of CBD in samples. [ABSTRACT FROM AUTHOR]

Residues of diquat (DQ), a bipyridyl herbicide, can pose a threat to human health. In this study, we designed two semi-antigens and obtained a highly specific monoclonal antibody (mAb) against DQ. The half maximal inhibitory concentration of mAb was 0.63 ng mL−1 with a limit of detection of 0.14 ng mL−1. Using this specific mAb, we developed an immunochromatographic assay with a cut-off value of 0.1 mg kg−1 in fruit samples, which was consistent with the HPLC-MS results, confirming that the test strips can be used in real samples. Our developed test strip can be used for screening DQ in food samples. Compared to instrumental methods, test strips offer several advantages. [ABSTRACT FROM AUTHOR]

Chlordimeform (CDM) is a broad-spectrum and highly effective insecticide and acaricide used to control pests in agriculture. We produced two monoclonal antibodies (mAbs) against CDM and developed an immunochromatographic assay to screen CDM in cucumbers and tomatoes. MAb 4A3 had high sensitivity with a 50% inhibitory concentration of 0.287 ng mL−1. The assay had a cut-off value of 25 μg kg−1 and a visual limit of detection (vLOD) of 1 μg kg−1 in cucumbers and a cut off value of 50 μg kg−1 and a vLOD of 2.5 μg kg−1 in tomatoes. The calculated limit of detection (cLOD) in cucumbers and tomatoes was 0.115 μg kg−1 and 0.215 μg kg−1, respectively. The recovery rates were 97.9% to 106.9% for cucumbers and 97.8% to 107.4% for tomatoes, consistent with the results obtained from indirect competitive ELISA. Our findings showed that the immunochromatographic assay is an efficient and accurate method for CDM detection in cucumbers and tomatoes. [ABSTRACT FROM AUTHOR]

Anthranilic diamide insecticides, including chlorantraniliprole (CHL), cyantraniliprole (CYA), cyclaniliprole (CYC), and tetrachlorantraniliprole (TEA), are widely used in agricultural production, resulting in potential risk to human health. In this study, we designed novel haptens for the preparation of a broad-specific monoclonal antibody (mAb) against CHL, CYA, CYC, and TEA simultaneously. The mAb 4F5 we produced belonged to the IgG1 subtype and had 50% inhibition concentration (IC50) values ranging from 0.06 to 0.19 ng mL−1 for all four anthranilic diamides. We further developed a mAb-based lateral flow immunochromatographic strip for the detection of anthranilic diamides in vegetables and fruits. Under optimal conditions, the strip provided cut-off values of 2.5, 5, 10, and 10 ng g−1 for CHL, CYA, CYC, and TEA, respectively, within 15 min. Collectively, these data show that the proposed strip assay is a convenient and practical method for the rapid screening of anthranilic diamides in food samples. [ABSTRACT FROM AUTHOR]

In this study, we developed a monoclonal antibody (mAb)-based colloidal gold immunochromatography assay (CG-ICA) strip for the rapid and sensitive detection of flubendiamide (FBD) in food samples. Our anti-FBD mAb 2B1 was highly specific and had a half-maximal inhibitory concentration (IC50) of 1.55 ng/mL under optimal conditions. It belongs to the IgG2a isotype and has a Kaff value of 1.52 × 109 mol/L. The strip provided a visual detection limit of 50 ng/g for both grapes and tomatoes, with a cut-off value of 1,000 ng/g and these qualitative results were observed within 15 min. For quantitative analysis, the calculated detection limits were 6 ng/g and 5 ng/g in grapes and tomatoes, respectively. The average recoveries of FBD ranged from 88.8% to 111.8% in grapes and 94.5% to 110.6% in tomatoes. The proposed strip assay is highly practical for screening FDB in food samples. [ABSTRACT FROM AUTHOR]

In this study, an excellent monoclonal antibody (mAb) was produced that could sensitively and specifically recognize Flu in fruit samples. The mAb belonged to the IgG2 subclass and had a half‐inhibitory concentration (IC50) of 0.59 ng/ml and a limit of detection (LOD) of 0.13 ng/ml. A cross‐reactivity test revealed that the mAb had good specificity for Flu. A gold nanoparticle‐based lateral‐flow immunochromatographic (ICA) strip was used for the rapid screening of Flu in fruit samples. The method had a visual cut‐off value of 10 µg/kg for Flu in three different fruit samples when evaluated with the naked eye. The LODs were 5.25, 3.13, and 4.64 µg/kg for Flu in apples, grapes, and oranges, respectively, as obtained with the aid of a strip scan reader. Therefore, this ICA strip assay represented a potential tool for the detection of Flu in fruit samples. [ABSTRACT FROM AUTHOR]

Mercury is a major pollutant in food crops. In this study, we synthesized an anti-mercury monoclonal antibody (mAb; IC50 was 0.606 ng mL−1) with high sensitivity and specificity and different immunogens and coating antigens and developed an immuno-chromatographic assay (ICA) for the detection of mercury in rice. The ICA strip had a visible detection limit of 20 ng g−1 and a cut-off value of 500 ng g−1 in rice. The performance of the ICA strip was consistent with that of ICP-MS and ic-ELISA. The recoveries of mercury in rice ranged from 94.5% to 113.7% with ic-ELISA and from 93.6% to 116.45% with ICP-MS. Qualitative analysis by ICA can be obtained with the naked eye. The ICA strip is an effective and practical method for the rapid and high-throughput determination of mercury in rice. [ABSTRACT FROM AUTHOR]

A monoclonal antibody against triamcinolone acetonide (TCA) and budesonide (BUD) was prepared using a hapten that was generated by introducing a carboxyl group into the structure of TCA. Based on the prepared monoclonal antibody, a gold nanoparticle-based lateral-flow immunoassay (GLFA) was developed with the ability to screen TCA and BUD in milk. The visible limits of detection of the GLFA for the analysis of TCA and BUD were 0.1 and 0.5 ng/mL with a cutoff value of 5 and 10 ng/mL, respectively, in milk. Average recoveries of TCA and BUD in milk were 92.0–102.2% and 96.0–98.8% with a good correlation between the results from the GLFA and LC-MS/MS analysis. These results demonstrated that the GLFA method for the rapid detection of TCA and BUD in milk samples is reliable and sensitive. [ABSTRACT FROM AUTHOR]

Butralin is a dinitrobenzene pesticide, has been widely used as a herbicide in many crops. Its high levels of residues threaten the ecological balance and human health. Therefore, establishment of a sensitive monoclonal antibody (mAb) for rapid detection of butralin residues is critical. In this study, special haptens were designed with good preservation of the characteristic structure of target compound. After mice immunization, a highly sensitive monoclonal antibody was produced. The half-maximum inhibitory concentration (IC 50) was 1.936 ng/mL. And we applied it to develop a method of lateral flow immunoassay (LFIA), with vLOD value of the LFIA strip to be 10 ng/mL. In watermelon and pear samples, the cLOD values of the LFIA strip were 0.432 ng/mL and 0.426 ng/mL, respectively. The recoveries of the developed method ranged from 94.4% ± 2.1%–112.1% ± 3.4% and 89% ± 5.4%–103% ± 4.1% in watermelons and pears samples, with a CV of 2.9%–3.4% and 2.2%–5.2%, respectively. The results demonstrated that the developed method showed great prospect in the detection and monitoring of butralin in real food samples. • New haptens of butralin was synthesized successfully. • Based on the anti- butralin monoclonal antibody, the strip assay was established. • The visual detection limit for flumioxazin was 5 ng/mL. • The strip assay can be applied in on-site monitoring of watermelon and pear samples. [ABSTRACT FROM AUTHOR]

• A novel AMT hapten was designed by adding a carboxyl group with 4-C spacer arms. • The sensitive and specific anti-AMT mAb was prepared based on hapten design. • The immunochromatographic assay was firstly developed for AMT rapid detection. • The established mehod can meet the requirements of MRLs for AMT residues in foods. Amitraz (AMT) is a broad-spectrum formamidine insecticide and acaricide. In this study, we produced an anti-AMT monoclonal antibody (mAb) with high performance. The half-maximal inhibitory concentration of the anti-AMT mAb was 4.418 ng/mL, the cross reactivity with other insecticides was negligible, and an affinity constant was 2.06 × 109 mmol/L. Additionally, we developed an immunochromatographic assay for the rapid detection of AMT residues in oranges, tomatoes, and eggplants. The cut-off values were 2000 μg/kg in oranges and tomato samples and 1000 μg/kg in eggplant samples and the calculated limits of detection were 14.521 μg/kg, 6.281 μg/kg, and 3.518 μg/kg in oranges, tomatoes, and eggplants, respectively, meeting the detection requirements for AMT in fruits and vegetables. The recovery rates ranged between 95.8 % and 105.2 %, consistent with the recovery rates obtained via LC-MS/MS. Our developed immunochromatographic assay can effectively, accurately, and rapidly determine AMT residues in oranges, tomatoes, and eggplants. [ABSTRACT FROM AUTHOR]

Residues of flumetralin, a dinitroaniline herbicide, in foods pose a health risk to humans. In this study, we produced a sensitive monoclonal antibody (mAb) against flumetralin and developed a gold nanoparticle-based lateral flow immunoassay (LFIA) strip for screening flumetralin in orange. The subtype of mAb 3F5 was IgG1 and had a half-maximal inhibitory concentration of 9.43 ng mL−1. The cross-reactivity assay indicated that mAb had good specificity. The LFIA strip had a visual limit of detection of 200 ng g−1 in orange. We obtained results with the naked eye within 15 min. The calculated LOD of the strip in orange was 33.26 ng g−1, with a linear detection of 80.72–1672.10 ng g−1. The strip had recovery rates ranging from 98.4% to 110.1%. Therefore, our developed method is an effective and reliable tool for the rapid detection of flumetralin in orange. [ABSTRACT FROM AUTHOR]

In this study, a highly specific and sensitive monoclonal antibody against dicofol (DIC) was prepared and used to create a colloidal gold immunochromatographic strip (ICS) for the quantitative analysis of DIC in liquorice and Angelica sinensis samples. We found that for both the liquorice and Angelica sinensis samples, the cut-off value for the ICS was 500 ng g−1, respectively, and using a colloidal gold test strip reader, the half-maximal inhibitory concentrations (IC50) were found to be 35 ng g−1 and 88 ng g−1, the limits of detection were 2 ng g−1 and 3 ng g−1, and the linear detection scopes (IC20–IC80) were from 6 to 201 ng g−1 and from 10 to 819 ng g−1, respectively. In the recovery test, we found that recoveries were within the range of 90.6% to 97.2% and the coefficients of variation were less than 8.6% in the intra-assay and inter-assay for the liquorice samples and the recoveries ranged from 90.8% to 97.3% and the coefficients of variation were less than 9.1% in the intra-assay and inter-assay for the Angelica sinensis samples. The established ICS assay could be used for the rapid quantitative screening of chemicals in Chinese traditional medicinal materials. [ABSTRACT FROM AUTHOR]

Butralin is a widely used dinitroaniline herbicide. Butralin residues in vegetables or fruits represent a threat to human health. In this study, we developed a rapid and sensitive gold-based lateral flow immunoassay (LFIA) for butralin detection in tomato and green pepper samples based on a screened monoclonal antibody (mAb) against butralin. The mAb possessed a half-maximal inhibitory concentration (IC50) of 12.7 ng/mL, with no cross-reactivity toward other dinitroaniline herbicides. The established LFIA strip had a visible limit of detection (LOD) of 50 ng/g and a cut-off value of 2000 ng/g in tomato and green pepper samples. According to the calibration curves for quantitative analysis, the calculated LODs of the LFIA strip were 4.7 ng/g and 4.3 ng/g in tomato and green pepper, respectively. The results were obtained within 10 min. The average recoveries ranged between 95.4% and 109.6% with a coefficient of variation (CV) of 4.3% to 7.1% in tomato samples and between 94.8% and 109.1% with a CV of 3.9% to 6.1% in green pepper samples. These data suggested that our proposed LFIA is a sensitive, specific, and reliable method for the rapid detection of butralin in real samples. [ABSTRACT FROM AUTHOR]

In this study, a monoclonal antibody (mAb) 1G5 against novobiocin with high sensitivity and specificity was prepared from a newly-designed hapten. According to the results of an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA), the 50%-inhibitory concentration of the anti-novobiocin mAb was 6.9 ng/mL and the cross-reactivity was less than 0.1% to its analogues. Furthermore, a rapid colloidal gold immunochromatographic assay (ICA) was successfully developed for the determination of novobiocin in spiked samples. Two calibration curves were established respectively, for beef and chicken samples. The ICA results showed a visual colorimetric value of 50 ng/mL and a cut-off value of 300 ng/mL in beef samples. The ICA results of chicken samples were almost the same as that of beef. When quantitative detection was performed using a strip reader, the detection ranges for quantitative analysis in beef and chicken were 23.7–287.5 and 19.7–263.8 µg/kg respectively. Recoveries were between 82.7 and 95.3% for beef samples with the coefficient of variation (CV) ranging from 2.5 to 5.1%. Recoveries were in the range of 89.6–105.5% with the CV ranging from 2.9% to 6.3% for chicken samples. Importantly, these results from the ICA were highly consistent with the results obtained by LC-MS/MS. Therefore, this ICA could be used as an alternative means for the rapid determination of NOV in a large number of beef and chicken samples. [ABSTRACT FROM AUTHOR]

tert-Butylhydroquinone (TBHQ) residues in foods pose a threat to human health. Therefore, it is necessary to develop a rapid method for TBHQ detection. In this study, a sensitive monoclonal antibody 5C3 (IgG2a subclass) against TBHQ was produced. It possessed a half maximal inhibitory concentration of 7.43 ng mL−1. A gold nanoparticle-based immunochromatographic assay (ICA) was established for the rapid and sensitive screening of TBHQ in soybean oil. Qualitative analysis results were obtained within 10 min and observed with the naked eye. The visual limit of detection (LOD) was 50 ng g−1 and the cut-off value was 1000 ng g−1. A hand-held strip reader was used for quantitative analysis, in which the calculated LOD was defined as 18.68 ng g−1. The average recoveries of TBHQ ranged from 89.55% ± 2.70% to 100.66% ± 3.02% for soybean oil, with a coefficient of variation of 2.89%–7.05%. Therefore, our developed ICA is a useful tool for the rapid and on-site detection of TBHQ in real food samples. [ABSTRACT FROM AUTHOR]

Sirolimus is a potent macrolide immunosuppressant, with a long half-life, a narrow therapeutic window, and large individual variations in pharmacokinetics. In this study, an indirect enzyme-linked immunosorbent assay (ic-ELISA) and a colloidal gold-based immunochromatographic strip were developed to establish a rapid and efficient clinical screening of sirolimus. The hapten for sirolimus was synthesized by the oximation reaction and then coupled to keyhole limpet hemocyanin (KLH) and bovine serum albumin (BSA) to prepare the immunogen and coating antigen. Based on highly specific monoclonal antibodies (mAbs), the 50% inhibitory concentration (IC50) of the optimized ic-ELISA was 1.54 ng mL−1 and the limit of detection (LOD) was 0.19 ng mL−1 in whole blood samples. Good specificity was revealed by its low cross-reactivity (CR) with several analogs of sirolimus. The visual limit of detection (vLOD) and cut-off values of the strip were 20 and 100 ng mL−1 in whole blood samples, as assessed by the naked eye. Therefore, both methods could be used as potentially rapid monitoring approaches for the detection of sirolimus in human whole blood. [ABSTRACT FROM AUTHOR]

Hyoscyamine (HSM), which acts as an antagonist of the acetylcholine muscarinic receptor and can induce a variety of distinct toxic syndromes in mammals (anti-cholinergic poisoning), is hazardous to human health. Therefore, it is urgent to develop a rapid, sensitive, and cost-effective method to determine HSM. A fluorescent microsphere based immunochromatographic assay was developed for this analyte and gold nanoparticles (AuNPs) were used as a comparison. A monoclonal antibody against HSM was prepared with a 50% inhibition concentration (IC50) of 1.17 ng mL−1, with no cross-reactivity with five drugs. Under optimized conditions, the cut off limits using the fluorescence-labeled monoclonal antibody strips were 10 ng mL−1 in 0.01 M PBS and 20 ng mL−1 in pork, pig urine, and honey samples, and the assay could be completed within 10 min. In comparison with a AuNP immunochromatographic assay, the developed method offered a higher coupling rate and lower amounts of antibodies. This approach could be used for simple, sensitive and rapid screening, and is suitable for on-site screening applications. [ABSTRACT FROM AUTHOR]

In this study, a highly specific and sensitive monoclonal antibody (mAb) against quinclorac (Qui) was prepared. Based on the selected mAb, 2G3, an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and an immunochromatographic strip assay were established for the detection of Qui in actual samples. The 50%-inhibitory concentration of mAb 2G3 against Qui was 48.763 ng mL−1. No cross-reaction with other quinolines indicated that mAb 2G3 had high specificity. The recovery of the established ic-ELISA method was in the range of 85.6% to 98.9%. The cut-off value of Qui in cucumber and tomato by immunochromatographic strip was 200 ng g−1. The analysis results of ic-ELISA and immunochromatographic strip assay were consistent with the results of LC-MS/MS, which further proved that the established ic-ELISA and immunochromatographic strip assay could provide valuable tools for the rapid detection of Qui residues in cucumber and tomato samples. [ABSTRACT FROM AUTHOR]

The excessive use of dapsone (DDS) in food animals could result in its accumulation in humans through the food chain, which in turn endangers human health. A sensitive monoclonal antibody (mAb) against DDS with a half inhibitory concentration (IC50) of 0.586 ng mL−1 was prepared in this study. Furthermore, a lateral flow immunoassay (LFIA) was established for the detection of DDS based on the anti-DDS mAb. Under optimized conditions, the developed LFIA had outstanding sensitivity with a visual limit of detection (vLOD) and a cut-off value of 1 ng mL−1 and 20 ng mL−1 for DDS in milk, respectively, which could be used for semi-quantitative detection of DDS. In milk sample analysis, a red test line on the LFIA strip signified <1 ng mL−1 DDS and a colorless test line signified >20 ng mL−1 DDS. In spiked samples and the recovery test, the results of the LFIA were in agreement with those of ic-ELISA, and the test using the LFIA strip could be completed within 15 minutes. Therefore, the established LFIA method in this study represents a reliable and compelling analysis for the rapid detection of DDS in milk. [ABSTRACT FROM AUTHOR]

We have developed a sensitive and rapid gold nanoparticle-based immunochromatographic strip (GNP-ICS) for the detection of phenacetin (PNCT) and paracetamol (PAP) using an anti-PNCT monoclonal antibody (mAb). The sensitive anti-PNCT mAb (2D6) had a half maximal inhibitory concentration (IC50) and limit of detection (LOD) of 3.51 and 0.21 ng mL−1, respectively. Additionally, its cross-reactivity with PAP was approximately 10.1%. The developed GNP-ICS assay based on GNP-labeled mAb was sensitive for the detection of PNCT with vLOD and cut-off values of 2.5 and 50 ng mL−1 respectively and a vLOD value of 25 ng mL−1 for PAP. Furthermore, the developed icELISA and GNP-ICS assays were applied to determine PNCT-spiked beverage samples without pretreatment, in addition to a kind of PAP-containing drug. The recoveries were validated using high performance liquid chromatography (HPLC). The results revealed that the developed GNP-ICS assay was reliable for the detection of PNCT in practical samples. [ABSTRACT FROM AUTHOR]

We prepared monoclonal antibodies (mAbs) against diminazene and used them in the development of a gold nanoparticle-based lateral-flow test (GNT) strip and indirect competitive enzyme-linked immunosorbent assay for the detection of diminazene in beef and beef liver samples. MAbs, which belong to the IgG2a subclass, had a half maximal inhibitory concentration of 0.04 ng mL−1. Based on cross-reactivity, mAb against diminazene was highly specific. The visual limit of detection (vLOD) of the GNT strip was 0.1 μg kg−1, and the cut-off value was 1 μg kg−1 in beef samples. The vLOD of the GNT assay was 0.1 μg kg−1, and the cut-off value was 2 μg kg−1 in beef liver samples. The average recoveries of diminazene ranged from 97.5% to 103.7% when using ic-ELISA. The accuracy of the developed GNT strip was confirmed by comparing the results with the ic-ELISA results. We developed a reliable GNT strip assay for the rapid detection of diminazene in beef and beef liver samples. [ABSTRACT FROM AUTHOR]

This report describes the development of a sensitive and broadly specific indirect competitive enzyme-linked immunosorbent assay (icELISA) and a gold nanoparticle-based immunochromatographic strip (GNP-ICS) assay for the detection of benzo[a]pyrene (B[a]P), using an anti-B[a]P monoclonal antibody (mAb). A broad-specific anti-B[a]P mAb (4E8) was raised from two types of haptens, with half maximal inhibitory concentrations and limits of detection (LOD) values of 2.51 and 0.54 ng mL−1, respectively. In addition, the cross-reactivity was up to 390% with structurally related compounds. The GNP-ICS assay based on a GNP-labeled mAb showed broad specificity in the detection of B[a]P and its analogues, with cut-off and visual LOD values of 100 and 10 ng mL−1, respectively. Furthermore, the recoveries from the developed icELISA and GNP-ICS assay in edible oil samples spiked with B[a]P were validated by high-performance liquid chromatography–fluorescence detection. The results revealed that the icELISA could reliably detect B[a]P in edible oils. [ABSTRACT FROM AUTHOR]

Chlorpheniramine (CPM) is an illegal additive found in herbal teas and health foods, and its excessive intake can cause health problems. In this study, a CPM monoclonal antibody (mAb) was developed based on a new type of hapten. The mAb was found to belong to the IgG2b subclass and showed high sensitivity and specificity when used in ELISA, with a half-maximal inhibitory concentration (IC50) of 0.98 ng mL−1 and cross-reactivity (CR) values below 1.8% when compared to antiallergic drugs. Based on the mAb produced, a fluorescent microsphere-based immunochromatographic strip assay (FM-ICS) and a gold nanoparticle-based immunochromatographic strip assay (GNP-ICS) were developed for the rapid and sensitive detection of CPM in herbal tea samples. Under optimal conditions, the cut-off values for the FM-ICS and GNP-ICS were 10 ng mL−1 and 100 ng mL−1, respectively, in herbal tea samples. The FM-ICS exhibited a higher sensitivity than GNP-ICS, but both could produce results within 15 min. In addition, a variety of high-throughput rapid immunoassay formats could be implemented based on this mAb for use as a convenient and reliable tool for the determination of CPM exposure in foods and the environment. [ABSTRACT FROM AUTHOR]

In this study, a highly specific and sensitive monoclonal antibody (mAb) against azoxystrobin (AZX) was prepared. Based on this mAb and the use of colloidal gold, an immunochromatographic strip (ICS) was developed to specifically detect AZX in cucumber, tomato, and cabbage samples. For qualitative detection, the cut off value using the ICS was 100 ng mL−1 using the naked eye and results could be seen within 10 min. For quantitative detection, the linear regression equations were obtained using a strip reader and the half maximal inhibitory concentrations (IC50) were found to be 4.16, 10.64, and 8.90 ng mL−1 in cucumber, tomato, and cabbage samples, the limit of detections (LODs) were 0.36, 1.03, and 0.92 ng mL−1, and the linear detection ranges (IC20–IC80) were respectively 0.64–21.77, 1.86–65.15, and 1.62–49.26 ng mL−1. The intra-assay recoveries range from 82.5% to 91.4%, with a coefficient of variation of less than 8.2%, and the inter-assay recoveries range from 81.7% to 92.5%, with the coefficient of variation less than 10.2%. The results demonstrated that the ICS could be used as a rapid tool for the qualitative and quantitative detection of AZX in vegetable samples. [ABSTRACT FROM AUTHOR]

We prepared a monoclonal antibody (mAb) which was sensitive and specific against xylazine based on a new hapten. The 50%-inhibitory concentration (IC50) of the mAb against xylazine was 0.399 ng mL−1 and the mAb was of the IgG2b subclass. A cross-reactivity test showed that the mAb had very high specificity for xylazine. An indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and gold nanoparticle-based lateral-flow test (GNT) strip were developed for the rapid screening of xylazine in milk samples. The limit of detection (LOD) and cut-off value of the GNT assay were evaluated to be 20 and 200 ng mL−1 in milk samples with the naked eye. The average recoveries of xylazine which was detected by the ic-ELISA ranged from 95.1% to 105.1%. Real samples were used to confirm the accuracy of the developed GNT strip. These results demonstrated that we had developed a very reliable method for rapid detection of xylazine in milk samples. [ABSTRACT FROM AUTHOR]

In this study, the monoclonal antibody-based indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and an immunochromatographic strip assay were developed for the rapid screening of robenidine hydrochloride (ROBH) in samples. The 50% inhibitory concentration (IC50) of ROBH was 0.927 ng mL−1, and the standard curve showed a linear correlation coefficient of 0.99932. There was no cross-reaction between ROBH and other commonly used anticoccidial drugs, which indicated that the monoclonal antibody had high specificity. The recoveries of ic-ELISA were in the range of 87.8% to 102.0%. The immunochromatographic strip assay displayed cut-off values of 10, 5 and 10 ng g−1 for shrimp, chicken breast and chicken liver samples, respectively. In addition, the results can be obtained within 10 min by naked eye observations. And in sample analysis, the results of ic-ELISA and the immunochromatographic strip assay were in accordance with those of LC-MS/MS. Thus, the ic-ELISA and immunochromatographic strip assay are effective methods for the detection of ROBH in shrimp, chicken breast and chicken liver samples. [ABSTRACT FROM AUTHOR]

In this study, a high sensitivity and specificity monoclonal antibody (mAb) was developed based on the hydroxy and carboxy-termini of ochratoxin A (OTA). A fluorescent microsphere immunochromatographic test strip (FM-ICTS) was assembled for the rapid detection the OTA in rice flour. Some relevant parameters were optimized including the best concentration of coating antigen and optimal diluent buffer composition. Under optimal conditions, the strip assay had a visual limit of detection (LOD) of 2 ng/mL and a cut-off value of 16 ng/mL for OTA in rice flour samples. By means of a strip scan reader, we obtained a quantitative measurement for OTA with an LOD of 1.27 ng/mL. No significant difference in the strip test results was seen when compared to an ic-ELISA assay or LC–MS/MS. This also shows, therefore, that the FM-ICTS has potential application for rapid and accurate quantitative detection in the market place. [ABSTRACT FROM AUTHOR]

In this study, a monoclonal antibody with selectivity for clopidol was produced based on a new hapten. The 50% inhibition concentration (IC50) for the developed ic-ELISA was 0.275 ng/mL. Cross-reactivity tests showed that the monoclonal antibody had high specificity for clopidol. Using this antibody, a lateral-flow colloidal gold immunoassay (LCGA) was created for the rapid screening of clopidol in raw chicken samples. With the naked eye, the cut-off value of the strip assay was 5 μg/kg for clopidol in chicken samples. Therefore, this LCGA provides a sensitive and rapid method for on-site detection of clopidol in chicken samples. [ABSTRACT FROM AUTHOR]

In developing countries, pesticides such as triazophos (TZP) are widely used in agriculture. However, the misuse TZP poses a threat to human health and the environment due to its high chemical and photochemical stability. In this study, we developed a lateral flow assay to determine TZP in cucumber. We produced anti-TZP monoclonal antibody with half inhibitory concentration of 2.013 ng/mL according to ELISA. Under optimum conditions, the lateral flow assay had TZP cut-off values of 100 ng/mL in 0.01 M PBS and 250 ng/mL in cucumber, and the results could be visualised with the naked eye in 5 min. our findings revealed that lateral flow assay is a rapid and sensitive method for detect TZP in cucumber. [ABSTRACT FROM AUTHOR]

Citreoviridin (CTV) is a toxic secondary metabolite that can be found in mouldy cereals. In this study, a sensitive and ethanol-tolerant anti-CTV monoclonal antibody (6B2) was produced with a 50% inhibition concentration of 4.1 ng/mL and then labelled using gold nanoparticle (GNP). Based on competitive inhibition of the binding of CTV-COOH-BSA conjugate sprayed onto a membrane to limited GNP-labelled antibody by free CTV in the samples, an easy-to-operate immunochromatographic strip (ICS) was developed for the fast screening of CTV in rice. The results are seen as a colour change within 5-10 min. We used relatively safe ethanol instead of highly toxic methanol or chloroform as the extraction solution and found a visible detection limit of 100 μg/kg and cut-off value of 1000 μg/kg. The developed ICS assay worked well and represented a reliable, safe, fast and a highthroughput method for the detection of CTV residues in rice samples. [ABSTRACT FROM AUTHOR]

In this study, an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and a gold immunochromatographic assay were developed to detect the furaltadone metabolite, 3-amino-5-morpholinomethyl-2-oxazolidinone (AMOZ). The detection of AMOZ was based on the AMOZ derivative 3-([2-nitrophenyl] methyleneamino)-5-morpholinomethyl-2-oxazolidinone (2-NPAMOZ). The monoclonal anti-2-NPAMOZ antibody 4G11, was prepared and exhibited a 50%-inhibitory concentration (IC50) of 0.049 ng/mL. Its cross-reactivity with structurally related analogues was less than 3%. This immunochromatographic assay was assembled for the rapid screening of AMOZ in catfish samples. The strip assay had a cut-off value of 0.1 μg/kg and a limit of detection (LOD) of 0.009 μg/kg. Analysis of AMOZ in catfish indicated that the results from the strip assay were highly comparable to results obtained using ic-ELISA and LC-MS/MS. Therefore, the colloidal gold (CG) immunoassay is a sensitive screening method for the detection of AMOZ residues in catfish samples. [ABSTRACT FROM AUTHOR]

In this study, we developed a monoclonal antibody against picoxystrobin (PIC). After cell fusion, four cell lines (3C2, 4D1, 4G4 and 5D4) capable of producing monoclonal antibodies against oxystrobin were obtained. The monoclonal antibody produced by the cell line 3C2 was the most sensitive to PIC, and its IC50 value was 0.1 ng/ml. The monoclonal antibody was then used to prepare immunochromatographic strips, and its cut-off values in both phosphate-buffered saline solution and cucumber samples were 50 and 100 ng/ml, respectively. It was concluded that the ICS can sensitively and rapidly detect PIC in cucumber samples. [ABSTRACT FROM AUTHOR]

In this study we developed a rapid and simple assay to detect RFP in fish using an immunochromatographic assay. We produced a sensitive and selective monoclonal antibody against RFP with a half-maximal inhibitory concentration (IC50) of 10.7 ng/mL. Fish samples were extracted with ethyl acetate, then centrifuged at 8000 rpm for 10 min, and concentrated by drying over nitrogen. We found under optimal conditions, that the RFP cut-off limits for the test strip was 10 µg/mL in both 0.01 M phosphate buffered saline and fish samples, and each test could be completed within 5 min. Therefore, immunochromatographic test can be used as a reliable, rapid, and sensitive method for the detection of RFP in fish. [ABSTRACT FROM AUTHOR]

Tricaine (TMS) is usually used as an anesthetic in the transportation of aquatic animals. However, when consumed, the numerous residual drug residues found in fish can cause a high risk to human health. Therefore, it is important to develop a rapid and sensitive method for the detection of this drug in food. Here we have developed a novel lateral-flow immunochromatographic strip (LF-ICS) method for the detection of TMS in fish samples, using a very effective anti-TMS monoclonal antibody with a half-maximal inhibitory concentration value of 31.79 ng/mL. After the K2CO3 and coating antigen concentrations were optimized in phosphate buffered saline (pH 7.4), the LF-ICS was used to determine TMS levels in fish samples spiked with varying concentrations of the drug. Following this, the values for the visual limit of detection and the cut-off for TMS were found to be less than 0.1 and 1 μg/mL, respectively. These results indicated that our developed LF-ICS is applicable for on-site screening of TMS in fish samples. [ABSTRACT FROM AUTHOR]

In this study, we produced a monoclonal antibody (mAb) 2F7 against cadmium (Cd) with IC50 of 0.20 ng/mL. The cross-reactivity of mAb 2F7 with other eight metals was < 1%. A fluorescent immunoassay strip was developed for the determination of Cd in rice. The cut-off value by visual inspection of the test strip was 50 μg/kg, and the quantitative detection range determined by the strip reader was 3.86–48.92 μg/kg. Both ic-ELISA and the fluorescent immunoassay strip can be used to detect Cd rice. Therefore, our developed fluorescent immunoassay strip may be an effective tool for detecting Cd in rice. [ABSTRACT FROM AUTHOR]

Lead (Pb) is a toxic metal that can accumulate in the body and negatively impact human health. In this study, we prepared a highly sensitive and specific monoclonal antibody, 2C3, that can recognize Pb(II) with an IC50 and linear range of 0.5 ng/mL and 0.08–1.86 ng/mL, respectively. Additionally, based on this antibody we developed a fluorescent test strip, which can be used for both qualitative and quantitative detection of Pb(II) in brown rice with a detection range of 4.67–47.8 ng/mL. Therefore, the method we developed has high sensitivity suitable for the detection of Pb(II) in brown rice. [ABSTRACT FROM AUTHOR]

In this study, we produced a specific monoclonal antibody (mAb) against triadimefon (TDF) and triadimenol (TDN). The half-maximal inhibitory concentration for TDF and TDN was 5.25 and 9.98 ng/mL, respectively, with a linear detection range (IC20–IC80) of 1.09–25.35 and 2.29–43.61 ng/mL, respectively. Subsequently, we developed a colloidal gold immunochromatography test strip for the analysis of TDF and TDN in tomato. The results obtained from the colloidal gold immunochromatography test strip were in accordance with those obtained from the indirect competitive enzyme-linked immunosorbent assay. The colloidal gold immunochromatography test strip is efficient and suitable for on-site detection of TDF and TDN. [ABSTRACT FROM AUTHOR]

The medicinal properties and toxicity of aconitine in traditional Chinese medicine have caused widespread concern. In this study, we screened a highly specific and sensitive monoclonal antibody with an IC50 of 3.65 ng/mL generated by immunizing mice and cell fusion, and the limits of detection of the ic-ELISA were 1.13 and 11.76 ng/mL. We then developed a colloidal gold test strip based on the antibody. For rapid detection of aconitine in herbs, the visual limit and detection limit of the test strip are 10 and 25 ng/mL, respectively; the results are obtained within 5 min and are visible to the naked eye. Therefore, the colloidal gold test strip is very suitable for on-site detection and quality screening of aconitine in Chinese herbal medicine. [ABSTRACT FROM AUTHOR]

Aminophylline (AMP), a bronchodilator drug, is a modified form of theophylline (the pharmacological active ingredient). AMP is often given to treat respiratory diseases, including bronchial asthma, blocked emphysema, panting bronchitis, and cardiogenic asthma. In this study, we developed a rapid and sensitive method to determine AMP concentration in mouse serum. A sensitive monoclonal antibody against AMP was produced by immunizing BALB/c mice with a well-characterized AMP2-keyhole limpet hemocyanin and coating antigen (hapten-AMP1-OVA). The coating antigen and goat anti-mouse IgG antibody were sprayed onto a nitrocellulose membrane representing the test and control lines, respectively. Under optimized conditions, the cut-off limits of the test strip were 50 ng/mL in 0.01 M phosphate buffered saline (pH 7.4) and 250 ng/mL in serum. The results were obtained within 10 min and revealed that this immunochromatographic strip test is a sensitive, rapid, and simple tool for the detection of AMP in serum. [ABSTRACT FROM AUTHOR]

The label is a significant factor when analyzing the performance of lateral flow immunoassays (LFIAs) in practical applications. In this study, we first produced a broad-specificity monoclonal antibody (mAb) against five antibacterial synergists (ASGs) whose subclass was IgG2b and affinity constant was 1.30 × 1010 L mol−1. Then, time-resolved fluorescent microspheres (TRFMs) and colloidal gold nanoparticles (CGs) were used to label the mAbs, and the two different label-based LFIAs were developed and compared for their ability to quantitatively detect ASGs in chicken samples. Under optimal conditions, the limits of detection (LODs) of the TRFM-based LFIA were 0.001–0.01 μg kg−1 and those of the CG-based LFIA were 0.01–0.11 μg kg−1. The sensitivity of the TRFM-based LFIA was higher than that of the CG-based LFIA. In addition, owing to the visible test zone of the CG-based LFIA, qualitative results can be easily obtained. Analysis of real samples showed that results from the two LFIAs were consistent with that of an ic-ELISA. [ABSTRACT FROM AUTHOR]

Cyclopiazonic acid (CPA) is an indole‐tetramine mycotoxin commonly produced by Penicillium and Aspergillus and is widely found in agricultural products, fermented food, and feed. Food contaminated with CPA poses a substantial health risk to consumers. Therefore, eco‐friendly immunoassays, including an indirect competitive enzyme‐linked immunosorbent assay (ic‐ELISA) and a lateral flow immunochromatographic strip (LFICS), were developed to monitor CPA in maize and rice samples. For this purpose, a monoclonal antibody (3H12) posed highly resistant to pH (5.6 to 9.6) and ethanol (≤50%) was generated by mouse immunization. Negative maize and rice samples or samples spiked with CPA were extracted with ethanol/0.01 M sodium borate buffer (4/1, v/v, pH 8.4). For ic–ELISA analysis, the limits of detection (LODs) were 0.48 and 0.28 ng/g for maize and rice samples, respectively. The recovery for spiked maize was 76.9% to 83.5% with the highest variable coefficient (CVmax) being 9.32%. For spiked rice, the recovery was 85.3% to 105.1% with a CVmax of 8.56%. For LFICS analysis, the visible LODs were 2.5 and 1 ng/g and cutoff values were 5 and 2.5 ng/g for maize and rice samples, respectively. The LFICS method gave results within 5 to 10 min, providing an auxiliary analytical tool for the rapid, sensitive, and portable screening of the massive samples onsite. [ABSTRACT FROM AUTHOR]

In this study, a kitasamycin (KIT) hapten was prepared through the o-carboxymethoxylamine method and used to produce a monoclonal antibody against KIT and josamycin (JOS). The half inhibition concentration for an indirect competitive enzyme-linked immunosorbent assay was 1.49 and 2.67 ng/mL, respectively. Based on this antibody, a gold immunochromatographic assay (GICA) was developed for the detection of KIT and JOS residues in milk and egg samples. A hand-held strip scanner was used for quantitative analysis, with limits of detection for KIT and JOS of 1.51 and 1.91 μg/L in milk, and 3.0 and 2.72 μg/kg in eggs. The proposed GICA was validated by LC–MS/MS, which indicated that the GICA method would be a useful tool for the on-site detection of KIT and JOS residues in milk and egg samples. [ABSTRACT FROM AUTHOR]

An anti-cimaterol (cima) monoclonal antibody, 2H8, was prepared and used to develop an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and an immunochromatographic test strip assay for the detection of cima, a newly described β-agonist. The half-maximal inhibitory concentration of the antibody was 1.56 ng/mL, and no cross-reactivity with other β-adrenergic agonists was observed. The antibody's limit of detection was 0.416 ng/mL, and its linear range of detection was 0.416–5.868 ng/mL. The recovery rates of cima in swine urine ranged from 86% to 92.5%, and the test strip had a cut-off value of 10 ng/mL. Both ic-ELISA and the developed strip assay are effective when detecting cima in swine urine. [ABSTRACT FROM AUTHOR]

Praziquantel (PZQ) is a broad-spectrum antiparasitic drug used in mammals and fish. In this study, we developed an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) for the detection of PZQ residues. The hapten PZQ-HS produced by introducing an amino group at a benzene ring synthesized the immunogen and the coating antigen with carrier proteins. Highly sensitive monoclonal antibodies (mAbs) were prepared following mouse immunization and cell fusion. Under optimum conditions, the half maximal inhibitory concentration of the cell line 4E9 was 7.4 ng/mL, and the working range was 2.4–22.8 ng/mL. Immunochromatographic strips (ICS) were developed for the rapid detection of PZQ residues in mackerel. The reliability of the ICS assay was verified with PZQ-negative mackerel and confirmed by HPLC/MS. The cutoff value for ICS was 50 ng/mL PZQ. Our findings revealed that ic-ELISA and ICS can be used for the rapid detection of PZQ in mackerel. [ABSTRACT FROM AUTHOR]