Gold Immunochromatographic Assay Research Articles

Rapid identification of triptolide in Tripterygium wilfordii products by gold immunochromatographic assay

Triptolide colloidal gold immunoassay strip was prepared by using colloidal gold labeled monoclonal antibody purified with saturated ammonium sulfate, triptolide succinate-bovine serum albumin and sheep anti-mouse IgG for the first time in our lab. Under optimized conditions, the detection limit of TP strip prepared in this study were determined to be 1 μg/mL and the total analysis time (including sample preparation) was less than 50 min. Sixty-six batches of Tripterygium wilfordii (T. wilfordii) and its adulterations were analyzed. It was found that 28 batches of T. wilfordii were positive as detected by the strips and 38 batches were negative. The result of test strip detection was in consistent with that from the UFLC-ESI-MS/MS method. Gold immunochromatography assay was demonstrated as a rapid, cost-effective, reliable technique for on-site screening of T. wilfordii and its preparations. The prepared colloidal gold immunoassay strip can be conveniently used for rapid identification of triptolide containing products.

Ultrasensitive detection of microcystin-LR with gold immunochromatographic assay assisted by a molecular imprinting technique

A simple and highly sensitive lateral flow immunochromatographic assay (LFICA) towards microcystin-LR (MC-LR) was proposed in this study. Molecular imprinting technique was combined with enzyme assisted colorimetric method to substantially enhance the sensitivity of traditional LFICA. The target, i.e., MC-LR molecular, was first separated from the complex matrix by molecularly-imprinted polymers (MIPs). Then, the obtained MC-LR was detected by LFICA based on the blue color generated by an enzyme–substrate reaction. Using the proposed assay, under optimal conditions, the determination of MC-LR was doable in a wide linear range from 0.1 ng/mL to 100 ng/mL with a detection limit of 0.04 ng/mL. In addition, the reliability of the developed method was validated by determining MC-LR contents in real samples. The overall results suggested that the neoteric LFICA method possess great potential in sensitive detection of MC-LR.

Quantitative Analysis of Immunochromatographic Strip Based on Convolutional Neural Network

Gold immunochromatographic assay (GICA) is a widespread rapid detection method with less cost but high efficiency. It is easy to operate and dispense with professional staff and equipment, which conforms to the trend of point-of-care testing that advocated by modern medicine. With the development and progression of medical detection technology, the qualitative analysis that could be easily performed with the naked eye is not satisfying anymore. In recent years, improving the performance of quantitative analysis of the GICA has become a hot research topic. However, the GICA is susceptible to noise interference due to various factors when used in the qualitative analysis in clinics. The rise of artificial intelligence has provided us with new ideas and directions. As a popular neural network in deep learning, convolutional neural network (CNN) has achieved excellent results in image processing and has been widely applied to many fields, including biomedical engineering. In this paper, CNN is applied to the image segmentation of gold immunochromatographic strip. The grayscale features of the pre-processed images are learned by the established CNN network, and then, the control and test lines are accurately extracted and further quantitative analysis is performed. The results show that the method proposed in this paper has a good segmentation effect on the GICA, and it also provides a new scheme for the quantitative analysis of the GICA.

Gold immunochromatographic assay for kitasamycin and josamycin residues screening in milk and egg samples

ABSTRACT 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.

Development of monoclonal antibody-based colloidal gold immunochromatographic assay for analysis of halofuginone in milk

ABSTRACTA highly sensitive, specific, and rapid immunochromatographic assay for halofuginone (HFG) has been developed. A well-characterized immunogenic conjugate of HFG with bovine serum albumin was produced using the N,N″-Carbonyldiimidazole method. A sensitive monoclonal antibody specific for HFG was then generated by immunizing BALB/c mic with the HFG conjugate. The antigen, HFG-CDI-ovalbumin and goat anti-mouse IgG were attached to a nitrocellulose membrane as the test line and the control line, respectively to produce an immunochromatographic test strip for the rapid detection of HFG in milk. Under optimized conditions, the detection limits of the semi-quantitative test strip for HFG were as low as 50 ng/mL in 0.01 M PBS (pH 7.4) and 100 ng/mL in milk. All the results were obtained within 5 min. The newly developed immunochromatographic assay provides a sensitive, rapid, and specific procedure for on-site screening for HFG.

Rapid Detection of Severe Fever with Thrombocytopenia Syndrome Virus via Colloidal Gold Immunochromatography Assay.

To develop the point-of-care testing method to facilitate the clinical detection of severe fever with thrombocytopenia syndrome virus (SFTSV), colloidal gold paper-based lateral flow immunochromatography test strips (LFITSs) have been fabricated for the rapid detection for the first time. The pH value and the amount of monoclonal antibody to prepare colloidal gold nanoparticle-labeled monoclonal antibody bioconjugates were optimized. In addition, 0.4% bovine serum albumin was considered to be the best concentration for blocking nitrocellulose membranes. Under optimal conditions, the limit of detection for SFTSV was as low as 1 ng/mL depending on a visual line. Meanwhile, the entire detection process required no more than 10 min with a volume of only 50 μL of the analyte solution. Moreover, paper-based LFITSs were evaluated in real samples of human serum of patients with satisfactory results. In addition, all strips were of high stability and specificity. In the light of advantages such as simple, portable, rapid, and low cost, the developed LFITSs will extensively come into service, especially in remote areas.

Clinical value of ELISA combined with colloidal gold immunochromatography in serum anti-CCP antibody detection of patients with rheumatoid arthritis

Objective To investigate the clincial value of ELISA combined with colloidal gold immunochromatography in the detection of anti-cyclic citrullinated peptide (CCP) antibody in patients with rheumatoid arthritis (RA). Methods From October 2014 to October 2016, 120 patients with RA who admitted to Fuyang People's Hospital were selected as RA group, and 120 healthy subjects were selected as the control group.Serum samples of patients were collected and tested for anti-CCP antibody by ELISA and ELISA combined with colloidal gold immunochromatography. Results ELISA method was lower than ELISA combined with colloidal gold immunochromatography test (χ2=3.943, P<0.05). The sensitivity, specificity, positive predictive value, negative predictive value of ELISA combined with colloidal gold immunochromatography assay were 93.33%, 91.67%, 84.85%, 96.49%, respectively, which were higher than single ELISA method (all P<0.05). Conclusion ELISA combined with colloidal gold immunochromatography assay for detection of serum anti-CCP antibody in patients with RA is effective and can obtain high diagnostic sensitivity and specificity, and it is worthy of promotion. Key words: Arthritis, rheumatoid; Enzyme-linked immunosorbent assay; Colloidal gold immunochromatography; serum anti-cyclic citrullinated peptide; Sensitivity and specificity

A GICA strip for Campylobacter jejuni real-time monitoring at meat production site

Campylobacter jejuni (C. jejuni) contamination occurs vastly and inevitably at the meat production site, which makes the real-time monitoring of C. jejuni an increasingly key part for the food safety control. Aiming to establish a C. jejuni on-site detection method, a colloidal gold immunochromatographic assay (GICA) was developed with a visual lowest detection limit of 102 CFU/μL of C. jejuni. Although the larger volume of antigen (bacteria) increased the difficulty of research, the developed GICA allowed a 10-min monitor of C. jejuni in pork samples at the production site with an accuracy of 93%, compared with traditional culture method. By analysing samples with the different cleanliness, both the specificity (0.94) and the accuracy (0.88) of meat samples versus culture were higher than those from fecal samples. By monitoring samples with a series of C. jejuni carriage loads, GICA performed more sensitive in pork samples, which both the specificity (0.98) and the accuracy (0.93) were higher than those in chicken meat samples. The developed GICA is a more portable and practical method for C. jejuni detection without the bacterial cultivation, which can provide a technical assistance for the real-time detection and the hazard control of C. jejuni in meat production.

Comparison of Chicken IgY and Mammalian IgG in Three Immunoassays for Detection of Sulfamethazine in Milk

Antibodies are the most important reagents for the development of highly sensitive and specific immunoassays to quantify analytes of interest in food and environmental samples. While immunoglobulin G (IgG)-derived antibodies from rabbit and mouse are traditionally employed in immunoassays, recent findings suggest that chicken egg yolk antibody (immunoglobulin Y (IgY)) provides several advantages over mammalian IgG. However, limited studies to date have examined the possibility of replacing IgG with IgY in immunoassays. In the current investigation, the performance of chicken IgY and IgG derived from rabbit and mouse was systematically compared in terms of sensitivity, specificity, and matrix effect under parallel conditions with three typical assay formats, specifically, indirect competitive enzyme-linked immunosorbent assay (icELISA), fluorescence polarization immunoassay (FPIA), and colloidal gold immunochromatographic assay (GICA), for detection of sulfamethazine (SMZ) as the reference molecule. We evaluated and discussed the influence of different coating antigens, tracers, and physicochemical factors on the performance of IgY and IgG in the immunoassays. Under optimized conditions, the sensitivities of icELISA (IC50 values of 6.70, 4.76, and 1.66 ng mL−1 with recoveries of 86.1–131.8% and precision of < 12%) and FPIA (IC50 values of 24.79, 20.87, and 10.83 ng mL−1 with recoveries of 81.8–120.2% and precision of < 17.3%) based on both IgY and IgG were sufficient to detect SMZ in milk while only GICA based on mouse IgG provided acceptable sensitivity. Our collective data indicate that IgY could be an acceptable alternative to mammalian antibodies in some situations (in icELISA and FPIA) for use in the development of effective immunoassays for screening and detection of veterinary drug residues in food samples.

A peptide/maltose-binding protein fusion protein used to replace the traditional antigen for immunological detection of deoxynivalenol in food and feed

A deoxynivalenol (DON) epitope clone (D8) was obtained by phage display technology using anti-DON monoclonal antibodies as a target molecule. Subsequently, a DON antigen mimic (D8-maltose-binding protein [MBP]) was synthesized by fusing the mimic epitope peptide with MBP. An enzyme-linked immunosorbent assay (ELISA) and urchin-like gold nanoparticle immunochromatographic assay was developed based on D8-MBP for detection of DON in maize and wheat. The half-maximal inhibitory concentration, lower detection limit, and linear range of the D8-MBP ELISA were 57.98 ± 0.97, 9.83, and 11.32–286.77 ng/mL, respectively. The sensitivity of the D8-MBP ELISA was nearly 2.5 times higher than that of traditional ELISA using DON-bovine serum albumin (BSA). The detection threshold of the colloidal gold immunochromatographic assay for D8-MBP was 25 ng/mL. Thus, D8-MBP could be used to replace the traditional DON-BSA antigen for the immunological detection of DON, permitting low cost, rapid detection of DON.

Rapid detection of aflatoxin B1 in medicinal materials of radix and rhizome by gold immunochromatographic assay

A rapid screening of the most toxic aflatoxin B1 (AFB1) in medicinal materials of radix and rhizome was performed by an immune chromatography method for the first time. The colloidal gold immunochromatographic strip was prepared after optimization of the conjugation of gold particles with monoclonal antibody, the test line and the control line. Under optimized conditions, the detection limit of the constructed test strip was as low as 0.1 ng mL−1 and the total analysis was conducted within 15 min by naked eyes. Four kinds of medicinal materials (Gastrodia elata, Poria cocos, Bletilla striata and Radix Angelicae Dahuricae) were investigated by the strip. Various complex matrixes pay a significant influence on the feasibility and effectiveness of the strip screening in medicinal materials. Aiming to the characteristics of selected medicinal materials, the screening was successfully proceeded with extraction by 70% methanol-water as well as three-fold dilution in Gastrodia elata and Radix Angelicae Dahuricae, 70% methanol-PBS as well as four-fold dilution in Poria cocos., and 60% methanol-water as well as four-fold dilution in Bletilla striata. Among the collected 40 samples, one was found to be positive of AFB1 with level above 5 μg kg−1. The result was in a good agreement with those obtained from LC-MS/MS determination (6.12 μg kg−1). The gold immunochromatographic strip was demonstrated as a rapid, cost-effective, reliable and on-site screening technique for mycotoxins in starch and polysaccharides-rich herbal medicines.

The effect of fish matrix on colloidal gold immunochromatographic assay of antibiotics: the source of interference and removal method

ABSTRACT The matrix effect is a serious problem for the immunoassay of antibiotic residues, which greatly restricts its real application in fishery products as well as other foodstuffs. Till now the related information on the colloidal gold immunochromatographic assay (GICA) is still limited. Therefore, five species of fish as samples, and the interference of main matrix components on the analysis of ciprofloxacin was investigated. Some water-soluble proteins were demonstrated to have significant affluence on GICA. Moreover, magnesium is also an important source of the matrix interference was revealed for the first time, and its interaction with some immunoglobin (Ig)G was assumed to be a possible reason for this. Based on these results, corresponding approaches for elimination of the interference were also explored. The matrix interference was fully eliminated and the sensitivity of GICA was increased about 8 times for the quantitative analysis of ciprofloxacin via acid pre-treatment followed by pH adjustment.

A gold immunochromatographic assay for simultaneous detection of parathion and triazophos in agricultural products

A multi-component gold immunochromatographic assay was developed for the rapid and simultaneous detection of parathion and triazophos in agricultural products.

Establishment and Evaluation of Colloidal Gold Immunochromatography Assay for Detection of EV71-IgM

Aim: The HFMD caused by EV71 virus has extremely high lethality and morbidity. EV71's pathogenesis has not understood thoroughly and the antiviral drug has been under development, which led to its emergence as a clinically fatal neurotropic virus. Early diagnosis is one of the main methods to reduce mortality. The aim of this study was to establish and evaluate a colloidal gold immunochromatography for qualitatively detecting the EV71-IgM in serum sample. Method: In this study, the different kinds of coating antigen were the focus of optimization. The pH value, particle size of the colloidal gold and other parameters and materials were also considered to achieve the good performance in detecting strips. The CA16-positive, EV71-positive and negative serum were used to compare and evaluate the accuracy and specificity of strips. Result: The accuracy of the strips coated by EV71-VP1-VP2-VP3 was higher than the EV71-VP1 strips 20%. The specificity of the EV71-VP1 strips was slightly higher than EV71-VP1-VP2-VP3 strips according to CA16 positive serum samples. Compared with commercial strips, this diagnostic method just needed 2 µL serum samples for detection, and the accuracy of the EV71-VP1-VP2-VP3 strips was significantly higher than the commercial strips. Conclusion: The developed method established in this study can apply to early diagnosis of HFMD caused by EV71 virus.

Matrix effect of five kinds of meat on colloidal gold immunochromatographic assay for sulfamethazine detection

A colloidal gold immunochromatographic assay (CG-ICA) was developed to detect sulfamethazine (SM2) residues in five kinds of meat: namely, chicken, pork, shrimp, beef, and fish.

Matrix effect of swine urine on time-resolved fluorescent nanobeads and colloidal gold immunochromatographic assay

ABSTRACT Immunochromatographic assay (ICA) is an efficient analytical technique and rapid, convenient, easy-to-use, low-cost, and on-site detection method that has been widely used to evaluate food safety. However, an important issue to be addressed for this method is its matrix effect. In this work, time-resolved fluorescent nanobead ICA (TRFN-ICA) and colloidal gold ICA (CG-ICA) were developed to detect clenbuterol in swine urine. Under optimized working conditions, the limits of detection of TRFN-ICA and CG-ICA were 16 and 68 pg/mL, respectively. The matrix effect on TRFN-ICA and CG-ICA was assessed in 20 swine urine samples. Results indicated that the sensitivity of TRFN-ICA was better than that of CG-ICA, and the detection time of the former was shorter than that of the latter. The matrix effect on TRFN-ICA was more serious than that on CG-ICA.

Gold Nanoparticle-Based Paper Sensor for Simultaneous Detection of 11 Benzimidazoles by One Monoclonal Antibody.

A colloidal gold immunochromatographic assay based on a generic monoclonal antibody is developed for the simultaneous detection of benzimidazoles and metabolite residues in milk samples. The monoclonal antibody is prepared using 2-(methoxycarbonylamino)-3H-benzimidazole-5-carboxylic acid as the hapten, and it can recognize 11 types of benzimidazoles simultaneously. The immunochromatographic strip is assembled and labeled using gold nanoparticles. This strip can detect 11 benzimidazoles including albendazole, albendazole s-oxide, albendazole sulfone, fenbendazole, fenbendazole sulfone, flubendazole, mebendazole, parbendazole, oxfendazole, oxibendazole, and carbendazim within 15 min in milk samples. Results are obtained visually with the naked eye, and the cutoff values and the visual limit of detection values for these benzimidazoles are 25, 6.25, 12.5, 12.5, 50, 25, 50, 50, 50, 6.25, and 25 ng mL-1 , and 6.25, 3.125, 3.125, 1.56, 12.5, 6.25, 12.5, 12.5, 6.25, 0.78, and 12.5 ng mL-1 , respectively. Results are also obtained using a hand-held strip scan reader, with calculated limit of detection values for these benzimidazoles of 0.83, 0.77, 1.83, 0.98, 7.67, 3.50, 3.96, 5.71, 0.92, 0.59, and 1.69 ng mL-1 , respectively. In short, the developed paper sensor is a useful tool for rapid and simple screening of residues of benzimidazoles in milk samples.

Development of an immunochromatographic strip for the rapid detection of maduramicin in chicken and egg samples

ABSTRACT Following the steps of antigen synthesis, immunization, cell fusion, ascites preparation and purification, a maduramicin (MD) monoclonal antibody (mAb) was produced. This MD-mAb demonstrated a 50% inhibition concentration value of 3.75 ng/ml, an affinity constant of 3.70 × 1010 l/mol, and the isotype was IgG3. The MD-mAb has no cross-reactivity with other polyether antibiotics. Using this MD-mAb, a gold immunochromatographic assay was developed to detect MD residues in chicken breast and egg samples. For semi-quantitative detection by the naked eye, the visual limit of detection was 5 ng/g in chicken breast, 10 ng/g in egg. Quantitative results can be obtained by a hand-held strip scan reader, with the detection range of 5.11–19.34 ng/g in chicken breast and 6.46–27.87 ng/g in egg. The strip test took 10 min to run in total. This strip assay is suitable for on-site detection of MD residues in chicken breast and egg samples.

Reduced thrombin activatable fibrinolysis inhibitor and enhanced proinflammatory cytokines in acute coronary syndrome

ObjectiveA study was made of the changes in the serum levels of thrombin activatable fibrinolysis inhibitor (TAFI), proinflammatory cytokines and acute phase proteins in the acute stage of acute coronary syndrome (ACS), in order to explore the possibility of using TAFI as a biomarker for ACS risk assessment. MethodsA total of 211 patients with ACS were enrolled, and healthy subjects were used as controls. Blood samples were taken within 24h after admission. Serum TAFI levels were determined by immunoturbidimetry. Serum levels of interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) were determined by enzyme linked immunosorbent assay (ELISA). Procalcitonin (PCT) and C-reactive protein (CRP) levels were measured by gold-immunochromatographic assay. ResultsSerum TAFI levels in ACS patients were significantly decreased versus the controls. The IL-1β, IL-6, TNF-α, PCT and CRP levels were markedly higher in the ACS patients than in the controls. Correlation analysis revealed a strong negative correlation between TAFI concentration and the IL-1β, IL-6, TNF-а, PCT and CRP levels in ACS patients and in controls. Multivariate logistic regression analysis suggested decreased serum TAFI to be an independent risk factor for ACS (OR 9.459; 95% CI 2.306–38.793; P=0.002). The area under the receiver operating characteristic (ROC) curve for TAFI was 0.872 (95% CI 0.787–0.909; P<0.001). The optimum TAFI cutoff point for the prediction of ACS was 24μg/ml, with a sensitivity of 75.83% and a specificity of 72.57%. ConclusionThese findings suggest that TAFI can be useful as a potential biomarker for ACS risk assessment.

Novel immunochromatographic assay based on Eu (III)-doped polystyrene nanoparticle-linker-monoclonal antibody for sensitive detection of Escherichia coli O157:H7

Colloidal gold immunochromatographic assay (ICA) has poor sensitivity when used for Escherichia coli O157:H7 (E. coli O157:H7) detection. Eu (III)-doped polystyrene nanoparticle (EuNP) has a large range of stokes shift, long decay time, and wide excitation spectrum and narrow emission spectra. EuNP has been used as novel probe in ICA to improve sensitivity. In this study, carboxyl-modified EuNPs were prepared with different linkers. ICA based on EuNP, EuNP-6 carbon chain (CC) complex, EuNP-200CC complex, EuNP-1000CC complex, and EuNP-streptavidin (EuNP-SA) complex were systematically compared for the detection of E. coli O157:H7. Under optimized working conditions, the limits of detection (LOD) of EuNP-ICA, EuNP-6CC-ICA, EuNP-200CC-ICA, EuNP-1000CC-ICA, and EuNP-SA-ICA were 9.54 × 102, 1.59 × 102, 3.18 × 102, 2.98 × 102, and 1.08 × 102 colony-forming units (CFU) mL−1, respectively. The linear ranges of EuNP-ICA, EuNP-6CC-ICA, EuNP-200CC-ICA, EuNP-1000CC-ICA, and EuNP-SA-ICA were 6.36 × 102–1.59 × 105, 3.18 × 102–1.59 × 105, 6.36 × 102–1.59 × 105, 6.36 × 102–1.59 × 105, and 8.0 × 101–1.59 × 105 CFU mL−1, respectively. EuNP-SA-ICA exhibited the highest sensitivity and the widest linear range with good specificity, accuracy, and precision. It could be a promising analytical method for detecting E. coli O157:H7 in food samples. EuNP-SA-ICA may be a good model for detecting low concentrations of other food-borne pathogens.