Lateral flow immunoassays (LFIAs) are a promising means of food quality control due to their rapidity and ease of implementation. Commonly, LFIA results are recorded based on the coloration of certain zones of test strips, in which immune complexes labeled with colored nanoparticles are formed. However, many nanoparticles have catalytic activity (are nanozymes) and can transform chromogenic substrates, enhancing coloration. Unfortunately, the choice of nanozyme size, shape modification technique, and degree of covering by immunoreagents for efficient LFIAs remain empirical.
The given work presents an application of different nanozymes for sensitive LFIAs for antibiotics in meat products. This is in high demand due to the numerous negative consequences of antibiotics entering the human body with food and the expansion of the list of antibiotics requiring extensive monitoring to protect consumer health.
A comparison was made for mono-, bi-, and tri-component nanoparticles of noble metals (gold, silver, and platinum) of different sizes and shapes as peroxidase-like nanozymes. The advantages of nanoparticles with a branched surface obtained by two-stage synthesis, namely, the formation of spherical gold nanoparticle cores and their partial surface modification with platinum, as catalysts were shown. Changes in the catalytic and antigen-binding activity of nanozyme–antibody complexes with varying surface densities of immobilized antibodies were considered. The limits of detection (LODs) for nanozyme-based LFIAs were reduced by tens of times compared to traditional LFIAs using spherical gold nanoparticles (AuNPs). For example, in the case of tetracycline, a 7.6-fold reduction was demonstrated using AuNPs as nanozymes instead of their direct photometry. Working with Au@Pt core–shell nanozymes led to a 20-30-fold reduction in LODs for chloramphenicol, tylosin, and tetracycline. The LFIAs were conducted by following the developed accelerated (15-20 min) protocols of sample preparation for raw and finished meat products.
This research was financially supported by the Russian Science Foundation under grant 24-16-00273.
