Use Of Lateral Flow Immunoassay Research Articles

Lateral flow immunoassay device to detect staphylococcal enterotoxin B (SEB) in durian candy.

Staphylococcal enterotoxin B (SEB), a potent enterotoxin produced by Staphylococcus aureus, has been implicated in incidences of Staphylococcal food poisoning in the Philippines. The use of lateral flow immunoassay devices to detect this toxin in solid food samples, like durian candy, at the point of sampling is constrained by the requirement for sample purification (e.g. centrifugation). This problem is also true with the other applications of LFIA devices on food samples. To overcome this challenge, a lateral flow immunoassay (LFIA) device capable of detecting SEB in unpurified durian candy sample was developed in this study. A modified LFIA device was assembled with three layers of glass fiber pads functioning as sample pads instead of a conventional cellulose fiber pad. Unlike with the cellulose fiber pad, the glass fiber sample pads acted as filter and allowed the flow of a 1:5 dilution of durian candy. The LFIA device applied to spiked 1:5 diluted durian candy samples achieved a visual limit of detection of 5ng/mL for SEB, which is twofold lower than reported for previous LFIA devices designed to detect SEB in food samples.

An Indigenous, Field-Deployable, Lateral Flow Immunochromatographic Assay Rapidly Detects Infectious Myonecrosis in Shrimp, Litopenaeus vannamei.

Shrimp farming is an important socioeconomic activity worldwide. Infectious myonecrosis virus (IMNV) is an important shrimp virus responsible for significant mortality (up to 70%) in Litopenaeus vannamei. We produced recombinant capsid protein (r-IMNV31) and obtained a highly specific antibody, anti-r-IMNV31, which was used in WOAH-approved ELISA and Western blot to detect IMNV. Further, anti-r-IMNV31 was employed in an indigenously developed lateral flow immunoassay (LFA) with gold nanoparticles as a visual label. Using LFA, IMNV could be detected rapidly (20min) from tissue homogenate with high specificity, reproducibility, and sensitivity (LOD = 103 viral particles). LFA was validated with "gold standard" qRT-PCR using 60 samples with high sensitivity (100%), specificity (86%). A Cohen's kappa coefficient of 0.86 suggested "good agreement" between LFA and qRT-PCR. With a shelf-life of ~ 1year at ambient temperature, the use of LFA in the on-site detection of IMNV by shrimp farmers will be a reality.

Evaluation of Simple Lateral Flow Immunoassays for Detection of SARS-CoV-2 Neutralizing Antibodies.

Immunization for the generation of protective antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has emerged to be highly effective in preventing hospital admission, need for intensive care treatment and high mortality in the current SARS-CoV-2 pandemic. Lateral flow immune assays (LFIAs) offer a simple and competitive option to monitor antibody production after vaccination. Here, we compared the diagnostic performance of three different lateral flow assays in detecting nucleocapsid protein (NP), S1 subunit (S1) and receptor binding domain (pseudo)-neutralizing antibodies (nRBD) in sera of 107 health care workers prior (V1), two weeks (V2) after first vaccination with BNT162b2 as well as three weeks (V3) and eight months later (V4). In sera at V1, overall specificity was >99%. At V3, LFIAs showed sensitivities between 98.1 and 100%. The comparison of S1 and nRBD LFIA with S1 ELISA and a focus reduction neutralization assay (FRNT) revealed high concordance at V3. Thus, the use of lateral flow immunoassays appears to have reasonable application in the short-term follow-up after vaccination for SARS-CoV-2.

Use of Lateral Flow Immunoassay to Characterize SARS-CoV-2 RBD-Specific Antibodies and Their Ability to React with the UK, SA and BR P.1 Variant RBDs.

Identifying anti-spike antibodies that exhibit strong neutralizing activity against current dominant circulating variants, and antibodies that are escaped by these variants, has important implications in the development of therapeutic and diagnostic solutions and in improving understanding of the humoral response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We characterized seven anti-SARS-CoV-2 receptor binding domain (RBD) antibodies for binding activity, pairing capability, and neutralization activity to SARS-CoV-2 and three variant RBDs via lateral flow immunoassays. The results allowed us to group these antibodies into three distinct epitope bins. Our studies showed that two antibodies had broadly potent neutralizing activity against SARS-CoV-2 and these variant RBDs and that one antibody did not neutralize the South African (SA) and Brazilian P.1 (BR P.1) RBDs. The antibody escaped by the SA and BR P.1 RBDs retained binding activity to SA and BR P.1 RBDs but was unable to induce neutralization. We demonstrated that lateral flow immunoassay could be a rapid and effective tool for antibody characterization, including epitope classification and antibody neutralization kinetics. The potential contributions of the mutations (N501Y, E484K, and K417N/T) contained in these variants’ RBDs to the antibody pairing capability, neutralization activity, and therapeutic antibody targeting strategy are discussed.

Development and comparison of immunochromatographic strips with four nanomaterial labels: Colloidal gold, new colloidal gold, multi-branched gold nanoflowers and Luminol-reduced Au nanoparticles for visual detection of Vibrio parahaemolyticus in seafood

In this study, the four nanomaterials: Traditional colloidal gold (AuNP), New colloidal gold (N-AuNP), Multi-branched gold nanoflowers (AuNF) and Luminol-reduced Au nanoparticles (L-AuNP) were respectively labeled with the monoclonal antibody against Vibrio parahaemolyticus (V. parahaemolyticus). We aimed to develop lateral flow immunoassays (LFIAs) with these nanomaterial labels and determine their performance in visual detection of V. parahaemolyticus. The results of four colloidal gold particle-labeled LFIAs and polymerase chain reaction (PCR) simultaneously detected in actual samples were to be highly consistent, indicating that strips have high accuracy. The four strips were also found to be stable up to 14 weeks under laboratory conditions. In terms of sensitivity, the N-AuNP-based strip was slightly better than the other three. For the N-AuNP-based strips, the difference between the results obtained for different batches was high consistency, and the stability was much better than that of the AuNP-, AuNF-and L-AuNP-based ones. Our results indicate that the N-AuNP can be better used as labels in immunochromatographic tests. It can also reduce the based antibodies, improve the detection sensitivity and reduce the production cost, thereby expanding the scale of production. The use of LFIA labeled with N-AuNP can be more effective, rapid and inexpensive methods for V. parahaemolyticus assay in on-site applications.

The use of lateral flow immunoassays for the detection of fentanyl in seized drug samples and postmortem urine.

The opioid crisis has continued to progress in the United States and the rest of the world. As this crisis continues, there is a pressing need for a rapid and cost-effective method for detecting fentanyl. Recent studies have suggested that lateral flow immunoassays (LFIs) could fill this technology gap. These qualitative paper-based assays contain antibodies designed to react with fentanyl and provide positive or negative results within a matter of minutes. In this study, two different LFI configurations for the detection of fentanyl were examined (dipsticks and cassettes) for effectiveness of detection using seized drug samples and postmortem urine samples. In the current study, 44 seized drug samples (32 fentanyl-positive, 12 fentanyl-negative) and 14 postmortem urine samples (10 fentanyl-positive, 4 fentanyl-negative) were analyzed. All 32 fentanyl-containing seized drug samples and 10 postmortem fentanyl-positive urine samples displayed positive LFI results with both LFI configurations. The fentanyl dipsticks displayed a sensitivity of 100%, a specificity of 75%, and an efficiency of 93.2% for seized drug samples and a sensitivity, specificity, and efficiency of 100% for postmortem urine. Analysis of the fentanyl cassettes displayed a sensitivity, specificity, and efficiency of 100% for seized drug samples and a sensitivity of 100%, a specificity of 75%, and an efficiency of 92.9% for postmortem urine samples. These data point to the utility of LFIs as a quick and low resource-dependent option for presumptive detection of fentanyl in real-world situations.

A comparison of 7 commercial anti-SARS-CoV-2 antibody immunoassays.

Serological testing in SARS-CoV-2 infection is gaining both patients' and clinicians' attention. Antibody assessment has potential multidirectional utility, hampered by the scarcity of clinical validation studies of the tests available on the market. Therefore, this study aimed to provide some evidence on the clinical utility of anti-SARS-CoV-2 commercial assays, based on the comparison of the results obtained with different methods. The study included 52 samples from patients and healthy volunteers. The control samples (n = 20) were obtained during the SARS-CoV-2 pandemic. The case cohort consisted of 32 consecutive patients referred to the Diagnostyka medical laboratory for anti-SARS-CoV-2 antibody testing. For the purpose of this study, the MAGLUMI chemiluminescent immunoassay (CLIA) was chosen as a comparative method. All samples were tested with this method, as well as with the Euroimmun enzyme-linked immunosorbent assay (ELISA) and five different lateral flow immunoassays (LFIAs). The results obtained in this study provide evidence for high overall concordance between the comparative CLIA method and both ELISA and different LFIAs. The agreement between CLIA and LFIAs was 92.3-98.0% for IgG and 90.0-96.1% for IgM, depending on the kit. The concordance between CLIA and ELISA was 92.3% for IgG and 75.0% for IgA (compared to the MAGLUMI CLIA IgM). The results obtained in this study provide evidence for high overall concordance between the comparative CLIA method and different LFIAs. This could justify the use of LFIAs in some settings, where automated assays are not available, provided that some limitations are considered.

Advantages of Highly Spherical Gold Nanoparticles as Labels for Lateral Flow Immunoassay.

The use of lateral flow immunoassays (LFIAs) for rapid on-site testing is restricted by their relatively high limit of detection (LoD). One possible way to decrease the LoD is to optimize nanoparticle properties that are used as labels. We compare two types of Au nanoparticles: usual quasispherical gold nanoparticles (C-GNPs), obtained by the Turkevich–Frens method, and superspherical gold nanoparticles (S-GNPs), obtained by a progressive overgrowth technique. Average diameters were 18.6–47.5 nm for C-GNPs and 20.2–90.4 nm for S-GNPs. Cardiomarker troponin I was considered as the target analyte. Adsorption and covalent conjugation with antibodies were tested for both GNP types. For C-GNPs, the minimal LoD was obtained with 33.7 nm nanoparticles, reaching 12.7 ng/mL for covalent immobilization and 9.9 ng/mL for adsorption. The average diameter of S-GNPs varied from 20.2 to 64.5 nm, which resulted in a decrease in LoD for an LFIA of troponin I from 3.4 to 1.2 ng/mL for covalent immobilization and from 2.9 to 2.0 ng/mL for adsorption. Thus, we obtained an 8-fold decrease in LoD (9.9 to 1.2 ng/mL) by using S-GNPs. This effect can be related to more effective antibody immobilization and improved S-GNP optical properties. The obtained results can improve LFIAs for various practically significant analytes.

Point-of-Care Devices to Detect Zika and Other Emerging Viruses.

Rapid diagnostic tests (point-of-care devices) are critical components of informed patient care and public health monitoring (surveillance applications). We propose that among the many rapid diagnostics platforms that have been tested or are in development, lateral flow immunoassays and synthetic biology-based diagnostics (including CRISPR-based diagnostics) represent the best overall options given their ease of use, scalability for manufacturing, sensitivity, and specificity. This review describes the identification of lateral flow immunoassay monoclonal antibody pairs that detect and distinguish between closely related pathogens and that are used in combination with functionalized multicolored nanoparticles and computational methods to deconvolute data. We also highlight the promise of synthetic biology-based diagnostic tests, which use synthetic genetic circuits that activate upon recognition of a pathogen-associated nucleic acid sequence, and discuss how the combined or parallel use of lateral flow immunoassays and synthetic biology tools may represent the future of scalable rapid diagnostics.

CHANGING TRENDS IN THE DIAGNOSIS OF MALARIA AND TYPHOID FEVER

CHANGING TRENDS IN THE DIAGNOSIS OF MALARIA AND TYPHOID FEVER

New approaches to wipe sampling methods for antineoplastic and other hazardous drugs in healthcare settings.

At the present time, the method of choice to determine surface contamination of the workplace with antineoplastic and other hazardous drugs is surface wipe sampling and subsequent sample analysis with a variety of analytical techniques. The purpose of this article is to review current methodology for determining the level of surface contamination with hazardous drugs in healthcare settings and to discuss recent advances in this area. In addition it will provide some guidance for conducting surface wipe sampling and sample analysis for these drugs in healthcare settings. Published studies on the use of wipe sampling to measure hazardous drugs on surfaces in healthcare settings drugs were reviewed. These studies include the use of well-documented chromatographic techniques for sample analysis in addition to newly evolving technology that provides rapid analysis of specific antineoplastic. Methodology for the analysis of surface wipe samples for hazardous drugs are reviewed, including the purposes, technical factors, sampling strategy, materials required, and limitations. The use of lateral flow immunoassay (LFIA) and fluorescence covalent microbead immunosorbent assay (FCMIA) for surface wipe sample evaluation is also discussed. Current recommendations are that all healthcare settings where antineoplastic and other hazardous drugs are handled include surface wipe sampling as part of a comprehensive hazardous drug-safe handling program. Surface wipe sampling may be used as a method to characterize potential occupational dermal exposure risk and to evaluate the effectiveness of implemented controls and the overall safety program. New technology, although currently limited in scope, may make wipe sampling for hazardous drugs more routine, less costly, and provide a shorter response time than classical analytical techniques now in use.

Evaluation of a modified lateral flow immunoassay for detection of high-sensitivity cardiac troponin I andmyoglobin

We prospectively evaluated the use of lateral flow immunoassay (LFIA) test modified with nanoparticles for combined detection of high-sensitivity cardiac troponin I (hs-cTnI) and myoglobin with the aim of excluding acute myocardial infarction (AMI). Specimens from 173 patients with symptoms suggestive of AMI were collected to measure hs-cTnI and myoglobin using an electrochemiluminescence immunoassay (ECLI) and the LFIA test modified with nanoparticles, and a comparison was performed between the modified method and a commercial LFIA test for detection of the two proteins. The accuracy of the modified LFIA test was also evaluated. Consistent agreement was observed in the quantitative comparison of 173 clinical samples using the modified LFIA and ECLI, and the modified method was more sensitive than the commercial LFIA test. The accuracy of the modified LFIA was <12% for both hs-cTnI and myoglobin. Thus, the new approach has great potential to improve LFIAs test, demonstrating its usefulness for simple screening applications and for sensitivity and quantitative immunoassays for diagnosis ofAMI.

Analytical Sensitivity Limits for Lateral Flow Immunoassays

A plethora of literature describes the use of lateral flow immunoassays (LFIA). Only a fraction of that contains information about possible analytical sensitivity or limit of detection. Accordingly, we have undertaken a comprehensive survey of the literature in PubMed and present here that fraction that has information on limits of detection or analytical sensitivity. Further detail of the search strategy is at http://www.finddiagnostics.org/news/resources/gordon\_michael\_latflow_immunoassays.pdf. In general, there is a need for rapid tests, such as LFIA, capable of being performed by unskilled operators yet providing rapid and reliable results in areas such as diagnosis of diseases in developing countries (1)(2), emergency room use (3), and biodefense(4). The utility of such tests is enhanced by the ability to determine analytes at very low concentrations. In LFIA, sample is added, the analyte and label are subjected to chromatography-like …