Enhancing the stability and sensitivity of a lateral flow immunoassay using stabilized AuNPs for the simultaneous detection of sulfonamides and antibacterial synergists in chicken meat

Surface decoration of gold nanoparticles (AuNPs) effectively improves the stability and sensitivity of a traditional AuNP-based lateral flow immunoassay (LFIA). AuNPs decorated with citric acid, tannic acid, polydopamine, and polyethylene glycol (PEG) have been reported. However, these prepared nanoparticles have yet to be compared with each other in the same analytical system. Here, we synthesized stabilized AuNPs decorated with these four ligands and explored their properties to enhance the stability and sensitivity of LFIA. The results revealed that AuNPs@PEG was the optimal signal probe with an average AuNP diameter of 30 nm. It demonstrated significant advantages in tolerating extreme conditions (concentration of NaCl at 0.34 M) and improved sensitivity (twofold better than traditional LFIA). AuNPs@PEG-based LFIA showed cut-off values of 20–20,000 μg/kg for 18 sulfonamides and 1.6–200 μg/kg for antibacterial synergists in chicken meat, and the corresponding limits of detection were 2.0–548.2 μg/kg and 0.2–9.5 μg/kg. In conclusion, we are the first to investigate the properties of four stabilized AuNPs, and AuNPs@PEG shows good promise for use in LFIA.