Lateral Flow Microimmunoassay (LFµIA) for the Reliable Quantification of Allergen Traces in Food Consumables

Abstract

Quality assurance and food safety are of great concern within the food industry because of unknown quantities of allergens often present in food. Therefore, there is an ongoing need to develop rapid, sensitive, and easy to use methods that serve as an alternative to mass spectrometry and enzyme-linked immunosorbent assay (ELISA) for monitoring food safety. Lateral flow immunoassay is one of the most used point-of-need devices for clinical, environmental, and food safety applications. Compared to traditional methods, it appears to be a simple and fast alternative for detecting food allergens. However, its reliability is frequently questioned due to the lack of quantitative information. In this study, a lateral flow microimmunoassay (LFµIA) is presented that integrates up to 36 spots in microarray format in a single strip, providing semi-quantitative information about the level of allergens, positive and negative controls, internal calibration, and hook effect. The LFµIA has been evaluated for the on-site simultaneous and reliable quantification of almond and peanut allergens as a proof of concept, demonstrating high sensitivity (185 and 229 µg/kg, respectively), selectivity (77%), and accuracy (RSD 5–25%) when analyzing commercial allergen-suspicious food consumables.

Advancing Chemical Education in Biotechnology Undergraduates: A Hands-On Laboratory Experiment to Teach the Lateral Flow Immunoassay for Biomarker Detection

“…To assist them, the instructor wrote two equations on the blackboard (see the Supporting Information). Throughout the printing, the instructor provided a concise explanation of the functioning of a liquid dispenser, which can be employed in designing microarrays on plastic chips and lateral flow strips in dot format …”

“…Throughout the printing, the instructor provided a concise explanation of the functioning of a liquid dispenser, which can be employed in designing microarrays on plastic chips and lateral flow strips in dot format. 20 With regard to the GAT results, the pH of the solution of AuNPs significantly affected the bioconjugation efficiency, with pH 8.0 and 9.0 proving to be optimal, facilitating the adsorption of antibodies onto the surface of the AuNPs. During the discussion of the results, the instructor elucidated that higher antibody concentrations and pH levels (5.0 μg/mL and pH 9.0, respectively) were reported as the optimal conditions in a GAT procedure (Figure 5A).…”

“…Unlike prior studies, this laboratory experiment guided students through the entire LFIA development process, providing a holistic learning experience. The experiment can be tailored for other assays, such as the detection of BSA, human immunoglobulin G, or food allergens, 20 among other biomarkers. The antibodies and standards for these assays are available from commercial sources at an affordable price (see the Supporting Information).…”

“…6 The conjugate pad is a glass fiber membrane containing a dehydrated conjugate solution. The conjugate solution consists of the detection antibodies labeled with a signal transducer, which, depending on its nature, provides a colorimetric, 7 fluorescent, 8 or electrochemical 9 output signal that can be measured with a detector. The conventional LFIA relies on 20 or 40 nm sized gold nanoparticles (AuNPs) that generate a red colorimetric signal that is visible by the naked eye.…”