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

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.

Hydrogel-based holographic sensors and biosensors: past, present, and future.

Hydrogel-based holographic sensors consist of a holographic pattern in a responsive hydrogel that diffracts light at different wavelengths depending on the dimensions and refractive index changes in the material. The material composition of hydrogels can be designed to be specifically responsive to different stimuli, and thus the diffraction pattern can correlate with the amount of analyte. According to this general principle, different approaches have been implemented to achieve label-free optical sensors and biosensors, with advantages such as easy fabrication or naked-eye detection. A review on the different approaches, sensing materials, measurement principles, and detection setups, and future perspectives is offered.