Lateral Flow Immunochromatographic Strip Research Articles

The importance of comparing quantitative faecal immunochemical tests (FIT) before selecting one for a population-based colorectal cancer screening programme

FIT for haemoglobin are now commonly used in many countries as the best, currently available, non-invasive test for colorectal cancer (CRC) in asymptomatic population screening programmes (1). FIT are available in two formats, qualitative, usually based on lateral-flow immunochromatographic test strips or cassettes, and quantitative, most often based on immunoturbidimetry, and performed on small benchtop analyzers. Quantitative FIT have a number of significant advantages over qualitative FIT, a major one being that analyses of faecal samples give estimates of the faecal haemoglobin concentrations (f-Hb) (2).

Comparison between gold nanoparticles and FITC as the labelling in lateral flow immunoassays for rapid detection of Ralstonia solanacearum

ABSTRACT Early prevention and monitoring of Ralstonia solanacearum (Rs) on nightshade is extremely critical for potent prevention and treatment of bacterial wilt disease. We developed two kinds of lateral flow immunochromatographic strip (LFICS) using gold nanoparticles (GNPs) and fluorescein isothiocyanate (FITC) for rapid diagnosis of plant bacterial wilt, caused by Ralstonia solanacearum (Rs), which both were based on double antibody sandwich method. Three monoclonal antibodies (McAb) highly specific to Rs were obtained by cell fusion and screening after four times of immunization with the strain GIM 1.76. Under optimized conditions, the limit of detection (LOD) with GNPs and FITC were 104 colony forming units per millilitre (CFU/mL) and 106 CFU/mL respectively, then the range detection correspondingly were 104–109 CFU/mL and 106–109 CFU/mL. On top of that, the developed immunoassay could be used for spot and point-of-care testing Rs on tomato seed, ginger seed, casuarina seed and display no cross-reaction with 43 other phytopathogenic strains that also could infect plants so as to cause plants diseases. These results demonstrated that we sucessfully developed two simple, effective and sensitive strips for monitoring bacterial wilt infection. Meanwhile, this is the first report about LFICS labelled by FITC for rapid detection of Rs, and it is the first time conformed that the sensitive of the LFICS with GNPs is significantly higher than FITC.

Development of an immunochromatographic lateral flow strip for the simultaneous detection of aminoglycoside residues in milk.

A colloidal gold-based immunochromatographic strip with a competitive format has been developed for the rapid, simultaneous, semi-quantitative and quantitative detection of several aminoglycoside residues in milk, including gentamicin sulfate (GM), neomycin sulfate (NEO) and kanamycin sulfate (KN). Three monoclonal antibodies against the three corresponding aminoglycosides were conjugated to colloidal gold particles and applied to the conjugate pads of the strip. The competitors [GM-bovine serum albumin (GM-BSA), NEO-BSA and KN-BSA conjugates] of GM, NEO and KN were immobilized onto a nitrocellulose (NC) membrane at three detection zones, T1, T2, and T3, respectively. The minimal cut-off values of the strip were 10 ng mL−1 for GM, and 100 ng mL−1 for NEO and KN, which are lower than the maximum residue levels (MRLs) established for aminoglycosides. The IC50 values of the strip were 0.737 ng mL−1, 8.971 ng mL−1 and 11.110 ng mL−1 for GM, NEO and KN respectively. In conclusion, the immunochromatographic lateral flow strip could be used for rapid, simultaneous, semi-quantitative and quantitative detection of GM, NEO and KN residues in milk.

Development of an ic-ELISA and immunochromatographic strip for detection of sparfloxacin in honey

ABSTRACT In this study, a sensitive monoclonal antibody (mAb) 3D5 against sparfloxacin (SPFX) was generated. Based on the mAb 3D5, an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) method was developed for the detection of SPFX in honey. The half maximal inhibitory concentration and limit of detection for the ic-ELISA method were 0.12 and 0.02 ng/mL, respectively. The experiments showed a negligible cross-reaction with other drugs. The average recovery rates for spiked SPFX honey extracts ranged from 90% to 101%, indicating an accepted accuracy. Furthermore, a lateral-flow immunochromatographic assay strip method with a cut-off value of 2 ng/mL was developed. Therefore, both of the developed methods are suitable for future use as rapid screening methods to detect and control the content of SPFX residues in honey samples.

Development of ic-ELISA and lateral-flow immunochromatographic strip for detection of vitamin B2 in an energy drink and vitamin tablets

ABSTRACT Vitamin B2 (riboflavin) is a water-soluble vitamin that has important roles in human health. In this study, we developed a sensitive and specific monoclonal antibody-based indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and lateral-flow immunochromatographic assay (ICA) strip for the rapid detection of vitamin B2. Following routine fusion and selection, the optimum monoclonal antibody against vitamin B2 was obtained. The 50% inhibitory concentration and limit of detection of ic-ELISA were 8.18 and 1.80 ng/mL, respectively. The cut-off value of the lateral-flow ICA strip was 50 ng/mL. The results revealed that our developed methods are suitable for the on-site detection and mass screening of vitamin B2 in food and pharmaceutical products.

Preparation and evaluation of Salmonella Enteritidis antigen conjugated with nanogold for screening of poultry flocks.

Aim:The present work aimed to develop lateral flow immunochromatographic strip (ICS) test for detection of Salmonella Enteritidis (SE) specific antibodies in chicken sera.Materials and Methods:A rapid lateral flow immunochromatographic test (LFIT) has been developed, in which SE Group D antigen labeled with the gold chloride molecules laid on the conjugate pad. Staphylococcus aureus protein A was used as capture antibody at the test line (T) of a nitrocellulose (NC) membrane and anti-SE antigen-specific rabbit antibodies were used as capture antibody at the control line (C) of the NC strip in the lateral flow layout device.Results:Using the developed LFIT, the minimal amount of SE-specific antibodies that can be detected in chicken serum sample was 1427 enzyme-linked immunosorbent assay (ELISA) unit/100 µl that was equal to 0.1 µg (Ab)/100 µl sample. 100 suspected serum samples collected from a poultry flock were tested with the prepared SE-LFIT kits and the locally prepared stained Salmonella antigen, and the results were compared with those obtained from examination of these samples with Salmonella Group D antibody ELISA kit as the gold standard test. The sensitivity, specificity, and accuracy of the prepared SE-LFIT antigen kits were 94.4%, 90%, and 94%, respectively, while those obtained with stained Salmonella antigen were 88.8%, 90%, and 89%, respectively.Conclusion:The developed test is a simple field rapid test of high sensitivity, specificity, and accuracy that can improve and facilitates rapid field surveillance of salmonellosis among chickens.

Rapid detection of tenuazonic acid in cereal and fruit juice using a lateral-flow immunochromatographic assay strip

ABSTRACTA lateral-flow immunochromatographic assay (ICA) strip was developed for determination of tenuazonic acid (TeA) using both semi-quantitative and quantitative methods. The ICA strip was based on produced anti-TeA monoclonal antibody, and could be used for TeA analysis in cereal and fruit juice, with visual limits of detection of 1600 ng/g and 400 ng/mL, and cut-off values of 6400 ng/g and 3200 ng/mL, respectively. The calculated limits of detection values were 126.4 ng/g and 65.3 ng/mL for wheat and apple juice samples, respectively. The recovery rates ranged from 90% to 129%. In summary, the developed strip was effective for TeA detection and would be suitable for on-site detection and rapid screening of samples.

Development of an antibody-based colloidal gold immunochromatographic lateral flow strip test for natamycin in milk and yoghurt samples

ABSTRACTAn immunochromatographic lateral flow strip test was developed for the detection of natamycin (Nata) residues in milk and cheese samples. Monoclonal antibody (mAb) against Nata was produced with a half maximal inhibitory concentration of 1.85 μg L−1. MAb conjugated with gold nanoparticles was the detection reagent. Nata conjugated with ovalbumin via the 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide method immobilized on a nitrocellulose membrane was the capture reagent. This semi-quantitative method required only 15 min to complete. The optimum concentrations of coating antigen and mAb were 0.15 µg mL−1 and 0.2 µg mL−1, respectively. Based on an optical density scanner, the visual limit of detection of Nata was 5 μg L−1 and 10 μg kg−1 in milk and yoghurt samples, respectively.

Development of ic-ELISA and lateral-flow immunochromatographic assay strip for the detection of citrinin in cereals

ABSTRACTA sensitive and specific anti-citrinin (anti-CIT) monoclonal antibody 1F2 was obtained following immunization and cell fusion. An indirect competitive enzyme-linked immunosorbent assay was developed with a 50% inhibitory concentration of 0.761 ng/mL and a limit of detection of 0.089 ng/mL. The recovery rates for CIT-spiked cereals (maize, wheat, and rice) ranged from 112% to 123%. A lateral-flow immunochromatographic assay was developed for both semi-quantitative and quantitative detection. With CIT-spiked cereals, the visual limit of detection was 8 ng/g and the cut-off value was 40 ng/g (semi-quantitative analysis with naked-eye detection). Using a strip scan reader, the calculated limit of detection was 1.28–1.8 ng/g for different CIT-spiked cereals. The recovery rates ranged from 110% to 127%. Therefore, both methods were effective for CIT detection and suitable for on-site detection and rapid screening of samples.

Development of ic-ELISA and lateral-flow immunochromatographic assay strip for the simultaneous detection of avermectin and ivermectin

ABSTRACTA sensitive monoclonal antibody, 1H2, was generated in this study that simultaneously recognizes avermectin and ivermectin. An indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) was developed, with 50% inhibitory concentrations of 0.491 ng/mL for avermectin and 0.770 ng/mL for ivermectin. A lateral-flow immunochromatographic assay (ICA) strip was also developed based on this monoclonal antibody for the semiquantitative and quantitative detection of avermectin and ivermectin. The semiquantitative (with the naked eye) analysis had visual limits of detection of 10 ng/mL for avermectin and 25 ng/mL for ivermectin, with cut-off values of 25 and 50 ng/mL, respectively. Using a strip scan reader, the quantitative results had calculated limits of detection of 1.3 ng/mL for avermectin and 2.9 ng/mL for ivermectin. In an analysis of raw milk samples, the recovery rates for the ic-ELISA ranged from 94% to 112% and for the ICA strip from 110% to 125%. Therefore, both methods are sensitive and effective for the on-site detection and rapid screening of samples, and are suitable for various other applications.

Development of ic-ELISA and lateral-flow immunochromatographic assay strip for the detection of vancomycin in raw milk and animal feed

ABSTRACTA highly sensitive monoclonal antibody (mAb) 3H4 against vancomycin (VAN) was prepared. Indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and lateral-flow immunochromatographic assay (ICA) were developed based on the mAb. The 50% inhibition concentration (IC50) value and limit of detection (LOD) value of ic-ELISA method for vancomycin were 0.59 and 0.06 ng/mL, and for norvancomycin were 1.51 and 0.13 ng/mL under optimized conditions as pH 7.4, 0.4% (m/v) NaCl, and 5% (v/v) acetonitrile. In lateral-flow ICA, the visual limit of detection (vLOD) value and cut-off values for vancomycin were 1 and 2.5 ng/mL, and for norvancomycin were 5 and 10 ng/mL under optimized conditions as pH 8.6 with 1 mg/mL coating antigen and 1 µg/mL gold nanoparticle-labeled mAb. In raw milk and animal feed samples, recovery rates from ic-ELISA ranged from 89.2% to 121.6%. The vLOD and cut-off value were 5–10 ng/g and 100–200 μg/kg, respectively. Therefore, both methods were sensitive, rapid, and effective for the on-site detection and rapid mass screening of samples.

Hollow Au-Ag Nanoparticles Labeled Immunochromatography Strip for Highly Sensitive Detection of Clenbuterol

The probe materials play a significant role in improving the detection efficiency and sensitivity of lateral-flow immunochromatographic test strip (ICTS). Unlike conventional ICTS assay usually uses single-component, solid gold nanoparticles as labeled probes, in our present study, a bimetallic, hollow Au-Ag nanoparticles (NPs) labeled ICTS was successfully developed for the detection of clenbuterol (CLE). The hollow Au-Ag NPs with different Au/Ag mole ratio and tunable size were synthesized by varying the volume ratio of [HAuCl4]:[Ag NPs] via the galvanic replacement reaction. The surface of hollow Ag-Au NPs was functionalized with 11-mercaptoundecanoic acid (MUA) for further covalently bonded with anti-CLE monoclonal antibody. Overall size of the Au-Ag NPs, size of the holes within individual NPs and also Au/Ag mole ratio have been systematically optimized to amplify both the visual inspection signals and the quantitative data. The sensitivity of optimized hollow Au-Ag NPs probes has been achieved even as low as 2 ppb in a short time (within 15 min), which is superior over the detection performance of conventional test strip using Au NPs. The optimized hollow Au-Ag NPs labeled test strip can be used as an ideal candidate for the rapid screening of CLE in food samples.

Development of a Simple, Fast, and Quantitative Lateral Flow Immunochromatographic Strip for Folic Acid

Folic acid (FA) is an important B vitamin naturally found in foods and also used in dietary supplements and food fortification. To monitor FA content is important to guarantee food quality and also to prevent its abuse in dietary supplements. In this work, we developed a simple and robust lateral flow immunochromatographic assay (ICA) for the routine screening of FA in food samples. FA was conjugated to carrier protein as immunogen and used to produce specific polyclonal antibody (pAb). The pAb was conjugated with gold nanoparticle and used to develop a lateral flow ICA. After the careful optimization of ICA conditions, the assay showed an IC50 of 51.8 ng mL−1 and linear range from 23.4 to 114.5 ng mL−1 for FA in assay buffer, with the assist of a DY6510 strip reader within 8 min. Using milk powder as a matrix model, after a 15-fold dilution to eliminate matrix effect, the ICA showed intra-assay recoveries from 94.2 to 107.0% with coefficient of variance (CV) below 15% and inter-assay recoveries from 91.4% to 111.3% with CV below 18%. Good agreement was obtained between the results of ICA and ciELISA and standard HPLC. It is an ideal screening tool for the fast monitoring of FA in a simple, fast, and low-cost manner.

A review of fluorescent signal-based lateral flow immunochromatographic strips

Fluorescent signal-based lateral flow immunochromatographic strips (FLFICS) have received great expectations since they effectively improve detection sensitivity with quantitative analysis, and still retain the advantages of simplicity, rapidness, and portability of a common lateral flow immunochromatographic strip (LFICS). Diverse fluorescent reporters have promoted development of FLFICS, such as fluorescent dyes, quantum dots (QDs), an up-converting phosphor (UCP), lanthanide labels, and other fluorescence nanoparticles. In this work, we discuss the different fluorescent reporters applied with LFICS and their unique properties as well as signal amplification strategies helping to enhance detection performance. Benefitting from these sensitive and accurate fluorescent labels, FLFICS commendably satisfies requirements for detecting different disease biomarkers in medical diagnosis, strict supervision of food safety, and water pollution. This work also gives a short introduction to trends in the development of future FLFICS technology.

A new lateral-flow immunochromatographic strip combined with quantum dot nanobeads and gold nanoflowers for rapid detection of tetrodotoxin

Tetrodotoxin (TTX) is a potent, low molecular weight analyte that can lead to fatal poisoning and requires a sensitive, rapid detection method. Here, we have developed a competitive, lateral-flow immunochromatographic strip combined with quantum dot nanobeads (QDNBs) and gold nanoflowers (AuNFs). This approach is called turn-on C-LFICS and it meets all testing requirements. Subsequent analysis revealed that this turn-on C-LFICS was rapid (8 min), sensitive (LOD = 0.2 ng mL-1), and quantitative (DLR = 1.56-100 ng mL-1), and had a positive signal readout (based on fluorescence quenching effects) for TTX detection. Moreover, it had superior signal brightness and a low background interference signal when compared with previous methods. Finally, it can function free of interference from the sample matrix and has a demonstrated recovery range of 85.5% to 119.7% in spiked samples. Taken together, these results show that our turn-on C-LFICS is an effective detection tool for TTX or other small molecules.

Development of indirect competitive ELISA and lateral-flow immunochromatographic assay strip for the detection of sterigmatocystin in cereal products

ABSTRACTSensitive and specific anti-sterigmatocystin (STG) monoclonal antibody (mAb) 4G10 was obtained by immunization and cell fusion. An indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) method and lateral-flow immunochromatographic assay (ICA) strip method were developed for the detection of STG in cereal products based on this mAb. The 50% inhibition concentration and limit of detection for the ic-ELISA method were 0.092 and 0.015 ng/mL, respectively. The visual limit of detection (vLOD) and cut-off value for the lateral-flow ICA strip method were 0.1 and 0.5 ng/mL, respectively. From the analysis of different cereal samples (wheat, maize and rice), the recovery rates ranged from 78.3% to 122.0% for the ic-ELISA method. For the lateral-flow ICA strip, the vLODs were 3, 1.2 and 3 ng/g, and the cut-off values were 12, 6 and 6 ng/g for wheat, maize and rice, respectively. Therefore, both of the developed methods are suitable for the on-site detection and rapid screening of numerous samples.

Development of Sensitive, Rapid, and Effective Immunoassays for the Detection of Vitamin B12 in Fortified Food and Nutritional Supplements

An indirect competitive enzyme-linked immunosorbent assay (Ic-ELISA) method and lateral-flow immunochromatographic (ICA) strip assay method were developed for the detection of vitamin B12 (four major forms, cyanocobalamin, hydroxocobalamin, adenosylcobalamin, and methylcobalamin) in different food products. The limit of detection and 50 % inhibitory concentration for the Ic-ELISA method were 0.065 and 0.43 ng/mL, respectively. The visual limit of detection and cutoff value for the lateral-flow ICA strip assay method were 1 and 4 ng/mL, respectively. For the detection of fortified food and nutritional supplements in vitamin tablets, energy drink, and infant milk powder samples, the recovery rates were in the range of 81 to 122 % for the Ic-ELISA method, and even the lowest content in infant milk powder was identified by the lateral-flow ICA strip assay. Therefore, both of these methods are sensitive, rapid, and effective and are suitable for the on-site detection and rapid screening of mass samples.

Development of ic-ELISA and lateral-flow immunochromatographic assay strip for the detection of folic acid in energy drinks and milk samples

ABSTRACTFolic acid (FA) is an important vitamin for human growth and development, especially for pregnant women. A sensitive, rapid, and accurate FA detection method is required to assess the nutritional quality and safety of foods. A monoclonal antibody against FA was prepared for the development of indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and lateral-flow immunochromatographic assay (ICA) strip. The 50% inhibitory concentration and limit of detection of ic-ELISA were 0.12 and 0.018 ng/ml, respectively. The visual limit of detection and cut-off values of the lateral-flow ICA strip were 0.5 and 2.5 ng/ml, respectively. Using the ICA strip, FA recovery rates were 89–98% from energy drinks and 73–87% for milk samples and were in good agreement with those obtained from the conventional microbiological assay method. Our developed methods are sensitive, convenient, effective, and suitable for on-site detection and rapid mass screening of food samples.

Development of a Monoclonal Antibody-Based Immunochromatographic Assay Detecting Ractopamine Residues in Swine Urine

A lateral-flow immunochromatographic assay (LFIA) using monoclonal antibody was developed for the rapid detection of ractopamine residues in swine urine. The assay procedure could be accomplished within 5 min, and the results of this qualitative one-step assay were evaluated visually according to whether test lines appeared or not. When applied to the swine urines, the detection limit and the half maximal inhibitory concentration (IC50) of the lateral-flow immunochromatographic test strip under an optical density scanner were calculated to be 0.1 ± 0.013 and 0.71 ± 0.056 ng/mL, respectively. The cut-off level was observed with the naked eye of 1 ng/mL for detection of ractopamine residue in swine urine. Parallel analysis of swine urine samples with ractopamine showed comparable results obtained from the LFIA and LC-MS/MS. Therefore, the described lateral-flow test strip can be used as a reliable, rapid and cost-effective on-site screening technique for the determination of ractopamine residues in swine urine.

Membrane-based lateral flow immunochromatographic strip with nanoparticles as reporters for detection: A review.

Membrane-based lateral flow immunochromatographic strip (LFICS) is widely used in various fields because of its simplicity, rapidity (detection within 10min), and low cost. However, early designs of membrane-based LFICS for preliminary screening only provide qualitative ("yes/no" signal) or semi-quantitative results without quantitative information. These designs often suffer from low-signal intensity and poor sensitivity and are only capable of single analyte detection, not simultaneous multiple detections. The performance of existing techniques used for detection using LFICS has been considerably improved by incorporating different kinds of nanoparticles (NPs) as reporters. NPs can serve as alternative labels and improve analytical sensitivity or limit of detection of LFICS because of their unique properties, such as optical absorption, fluorescence spectra, and magnetic properties. The controlled manipulation of NPs allows simultaneous or multiple detections by using membrane-based LFICS. In this review, we discuss how colored (e.g., colloidal gold, carbon, and colloidal selenium NPs), luminescent (e.g., quantum dots, up-converting phosphor NPs, and dye-doped NPs), and magnetic NPs are integrated into membrane-based LFICS for the detection of target analytes. Gold NPs are also featured because of their wide applications. Different types and unique properties of NPs are briefly explained. This review focuses on examples of NP-based LFICS to illustrate novel concepts in various devices with potential applications as screening tools. This review also highlights the superiority of NP-based approaches over existing conventional strategies for clinical analysis, food safety, and environmental monitoring. This paper is concluded by a short section on future research trends regarding NP-based LFICS.