The use of Au@Pt nanozyme to perform ultrasensitive immunochromatographic detection of banned pork additives in meat products

In this study, an ultrasensitive immunochromatographic determination of the muscle tissue of pork was developed. Myoglobin (MG), a protein contained in skeletal muscles, was proposed as a molecular identifier of pork via the application of specific monoclonal antibodies (MAb) recognizing the porcine form of this protein. The immunochromatographic analysis (ICA) was based on the sandwich format with specific MAb labeled by a nanozyme – core@shell Au@Pt nanoparticles having peroxidase-mimicking catalytic properties. Several MAb–Au@Pt conjugates were synthesized by varying ratios of components; the one ensuring the best analytical parameters of the ICA was chosen. The enhancement of bands’ coloration on the test strips was promoted by the product of the reaction catalyzed by the nanozyme, which enabled the lowering visual limit of detection (LOD) of MG in the buffer down to 0.15 ng/mL. The amplification enabled to decrease in the LOD of MG by ∼30 times compared to the ICA based on gold nanoparticles as a traditional label and more than 3 times compared to the ICA based on the colorimetric detection of the nanozyme. The duration of the enhanced analysis was 23 min, including the reaction with the substrate. The rapid and simple procedure of sample preparation for extracting MG from meat samples before the ICA was proposed. The specificity of the developed test system was high: no interaction was detected upon analyzing other meat samples except pork. Testing of raw meat mixtures showed ultrasensitive detection of pork additives in beef, chicken, and turkey meat – down to 0.005%.