Development of a signal-enhanced LFIA based on tyramine-induced AuNPs aggregation for sensitive detection of danofloxacin.

A signal-enhanced LFIA based on tyramine (TYR)-induced AuNPs aggregation has been developed for the sensitive detection of danofloxacin (DAN). In the model, the hydroxyl radical produced by HRP catalyzing H2O2 can trigger the TYR-AuNPs to aggregate on the T or C line for enhancing the detection signal. The linear range of TYR-AuNPs LFIA was 0.25-5 ng mL-1 with the limit of detection (LOD) of 0.032 ng mL-1, and the LOD was 8-fold lower than that of the traditional AuNPs LFIA (0.26 ng mL-1). The TYR-AuNPs LFIA could be used with the naked eyes to qualitatively detect DAN with a cut-off limit of 2.5 ng mL-1, which was 4-fold lower than that of the traditional AuNPs LFIA (10 ng mL-1). The recoveries of TYR-AuNPs LFIA were 86.04-105.14% and 92.41-110.19%, with the coefficient of variation of 1.71-2.05% and 4.42-5.89% in chicken and pork, respectively.