Colloidal Gold Immunochromatographic Assay for Rapid Detection of Carbadox and Cyadox in Chicken Breast

Rapid immunoassays for the detection of quinoxalines and their metabolites residues in animal-derived foods: A review

Quinoxalines are a class of veterinary drugs with antibacterial and growth-promoting functions. They are often widely used to treat and prevent animal diseases and are illegally used as animal growth promoters to increase economic benefits. Quinoxalines could be easily metabolized in animals to various residue markers and remain in animal-derived foods, which would pose a serious threat to human health. Consequently, it is necessary to detect the residues of quinoxalines and their metabolites. This article reviewed and evaluated immunoassays for quinoxalines and their metabolites in animal-derived foods, mainly including enzyme-linked immunosorbent assays, fluorescence immunosorbent assays, immunochromatography, and surface plasmon resonance biosensors. In addition, we deeply explored the design of haptens for quinoxalines and their metabolites and analyzed the effect of haptens on antibody performance. This paper aims to provide guidance and references for their accurate and sensitive detection, thereby ensuring food safety and human public health.

Reduction and Hydroxylation Metabolites of Mequindox in Holothurian Analysis by Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry

This research proposed and validated an LC-MSMS method for five reduction and hydroxylation metabolites of Mequindox (MEQ) as well as the precursor in holothurian samples. Specially, three hydroxylation metabolites (2-isoethanol-mequindox, M3, 2-isoethanol-1-desoxymequindox, M4 and 2-isoethanol-4-desoxymequindox, M5) are novel for analysis. Target compounds were extracted with methanol and ethyl acetate in turn without any complicated acidolysis, alkaline hydrolysis or enzymolysis steps. Samples were further purified with C18 solid-phase extraction cartridges for LC-MSMS analysis. Mean recoveries in spiked samples ranged from 81 to 107% with intra-day relative standard deviation (RSD) and inter-day RSD <11.2 and 9.9%, respectively. Limit of detection was determined based on signal-to-noise ratio ≥3 ranged from 0.16 to 2.11 μg kg-1 for each target. The validated protocol was successfully applied for commercial holothurian samples with a positive rate at 13.3%. And concentrations of hydroxylation metabolites were higher than reduction metabolites and precursor MEQ in positive samples.

Development of monoclonal antibodies for the detection of diuron in water and sugarcane and their application in immunochromatographic strips

Diuron (DR) as a chemical herbicide persists in soil and water for a long time and causes extensive harm to humans. We have produced an excellent monoclonal antibody (mAb) with the ability to sensitively and specifically recognize DR in water and sugarcane samples. The semi-inhibitory concentration (IC₅₀) of this mAb was 0.28 ng mL^-1, and the limit of detection (LOD) was 0.07 ng mL^-1. Based on the mAb, an immunochromatographic assay (ICA) strip was developed. The visual detection limits of the strip assay were estimated, and the critical values of DR in water and sugarcane samples were determined to be 5 and 10 ng mL^-1, respectively, when assessed by the naked eye. The ICA strip was validated by HPLC-MS for water and sugarcane samples which had been spiked with DR. This ICA strip could be a useful tool for in-site and rapid detection of DR in water and sugarcane samples.

Highly sensitive time-resolved fluoroimmunoassay for the quantitative onsite detection of Alternaria longipes in tobacco

AIMS

Alternaria longipes is a causal agent of brown spot of tobacco, which remains a serious threat to tobacco production. Herein, we established a detection method for A. longipes in tobacco samples based on the principle of time-resolved fluoroimmunoassay, in order to fulfil the requirement of rapid, sensitive and accurate detection in situ.

METHODS AND RESULTS

A monoclonal antibody against A. longipes was generated, and its purity and titration were assessed using western blot and ELISA. The size of europium (III) nanospheres was measured to confirm successful antibody conjugation. The method described here can detect A. longipes protein lysates as low as 0.78 ng ml-1 , with recovery rates ranging from 85.96% to 99.67% in spiked tobacco. The specificity was also confirmed using a panel of microorganisms.

CONCLUSIONS

The fluorescent strips allow rapid and sensitive onsite detection of A. longipes in tobacco samples, with high accuracy, specificity, and repeatability.

SIGNIFICANCE AND IMPACT OF THE STUDY

This novel detection method provides convenience of using crude samples without complex procedures, and therefore allows rapid onsite detection by end users and quick responses towards A. longipes, which is critical for disease control and elimination of phytopathogens.

Development of a Rapid Gold Nanoparticle Immunochromatographic Strip Based on the Nanobody for Detecting 2,4-DichloRophenoxyacetic Acid

2,4-Dichlorophenoxyacetic acid (2,4-D) is a systemic conductive herbicide widely used across the world. With the large-scale and continuous use of 2,4-D, its possible harm to the environment and non-target organisms has attracted increasing attention, and the construction of a stable rapid on-site detection method is particularly important. In order to achieve on-site rapid detection of 2,4-D, we developed a gold nanoparticle immunochromatographic strip method with the visual elimination value was 50 ng/mL, and a quantitative detection limit of 11 ng/mL based on a nanobody. By combing with the color snap, the immunochromatographic strip could quantitatively analyze the amounts of 2,4-D. Meanwhile, a colorimetric card based on the true color of the test strips was developed for the qualitative analysis of 2,4-D on-site. The samples (water, fruits and vegetables) with and without 2,4-D were detected by the immunochromatographic strips, and the results showed the accuracy and reliability. Thus, this assay is a rapid and simple on-site analytical tool to detect and quantify 2,4-D levels in environmental samples, and the analytical results can be obtained in about ten minutes. In addition, the nanobody technology used in this study provides an inexhaustible supply of a relatively stable antibodies that can be archived as a nanobody, plasmid or even its sequence.

A paper-based sensor for rapid and ultrasensitive detection of ibuprofen in water and herbal tea

As the use of non-steroidal anti-inflammatory drugs (NSAIDS) increases, their side effects have also attracted attention. Ibuprofen is one of the most widely-used NSAIDs. In this study, we screened the highly-sensitive and specific antibody 6E10, with an IC₅₀ of 1.92 ng mL^-1, and a linear range of 0.53-6.97 ng mL^-1. In this study, we developed a rapid lateral flow immunochromatographic assay (ICA) strip method to detect ibuprofen in water or herbal tea. The cut-off limit of the strip is 10 ng mL^-1 in water, and concentrations as low as 1 ng mL^-1 can be detected in herbal tea samples, with the results obtained by the naked eye within 6 min. All the data were confirmed by high performance liquid chromatography-quadrupole time of flight-mass spectrometry (HPLC-QTOF-MS). This lateral-flow ICA strip is thus a rapid tool for on-site detection and screening of ibuprofen in water and herbal tea.

Development of a Colloidal Gold Immunochromatographic Strip for the Rapid Detection of Channel Catfish Virus

BACKGROUND

Channel catfish virus disease (CCVD) has resulted in great economic losses and has restricted the development of fisheries. There is therefore, a need for rapid and efficient diagnostic methods to control the spread of CCVD.

OBJECTIVE

A colloidal gold immunochromatographic strip has been developed for the detection of CCVD.

METHODS

In this study, a colloidal gold immunochromatographic strip for channel catfish virus (CCV) detection was developed using the monoclonal antibody 8B6 conjugated with colloidal gold as the detector antibody. A rabbit anti-CCV antibody was used as the capture complex at the test line, and a goat anti-mouse IgG antibody was used as the capture antibody at the control line. The strip was characterized in its specificity, sensitivity, and stability. In addition, an infection experiment was performed to test the applicability of the test strip.

RESULT

The strip was able to detect concentrations of the virus (104 tissue culture infective dose (TCID50)/mL) and showed analytical specificity when tested against other viral pathogens. The strips were still usable after 30 days of storage at 60°C. It was possible to detect CCV experimentally in infected fish within 10-15 min of using the strip.

CONCLUSIONS

The strip can be used as a rapid and convenient tool for on-site diagnosis to control outbreaks and the spread of CCVD.

HIGHLIGHTS

The immunochromatographic strip was the first to be developed and applied for the detection of CCVD.

Ten Years of Lateral Flow Immunoassay Technique Applications: Trends, Challenges and Future Perspectives

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

Development of enzyme linked immunosorbent assay and lateral flow immunoassay for the rapid detection of dapsone in milk

High-throughput rapid detection of dapsone in milk without pretreatment.

Europium nanosphere-based fluorescence strip sensor for ultrasensitive and quantitative determination of fumonisin B1

Contamination of grains and related products by fumonisins (FBs) is increasingly becoming a serious food security issue. The aim of this work was to develop a europium fluorescent microsphere-based time-resolved fluorescence immunochromatographic assay (TRFICA) for FB₁ detection in different grains, including corn, corn flour, wheat, rice and brown rice. Standard curves for the five types of grain matrix were established, and showed good linearity (R² > 0.975), LOD of 8.26 μg kg^-1, and a wide working range of 13.81-1000 μg kg^-1. The recoveries of TRFICA for FB₁ detection ranged from 82.85-103.62% with variation coefficients of 1.92-15.33%. Two corn reference materials and other natural samples were tested using TRFICA. The same samples analyzed by liquid chromatography tandem mass spectrometry further confirmed the TRFICA results. The entire detection time of TRFICA was within 30 min. Thus, this developed TRFICA can be used for onsite detection and quantitation of FB₁ in grains.

Rapid and Sensitive Immunochromatographic Method-Based Monoclonal Antibody for the Quantitative Detection of Metalaxyl in Tobacco

In this study, we prepared a monoclonal antibody (mAb) against metalaxyl (Met) with a half-maximum inhibitory concentration (IC₅₀) of 0.54 ng/mL based on a new hapten, and a gold nanoparticle-based immunochromatographic assay (GICA) was developed for the rapid detection of Met residues in tobacco. Under optimal conditions, even with the naked eye, one can see the semiquantitative analysis results. The naked eye detection limit of Met in tobacco is 25 μg/kg, and the detection threshold is 100 μg/kg. In addition, the cross-reactivity test shows that the mAb has good specificity for Met, and the GICA results have a good correlation with the indirect competitive enzyme-linked immunosorbent assay and liquid chromatography with tandem mass spectrometry test results, which show that the method is feasible and reliable and are more convenient and quicker than the methods using instrumentation for detection. Therefore, GICA may provide a useful tool for the rapid screening and detection of Met residues in tobacco.