Development of fluorescent artificial receptors for specific recognition and rapid detection of Escherichia coli O157:H7.

Development of rapid, low-cost, and sensitive sensors for monitoring Escherichia coli (E. coli) O157:H7 is very necessary and urgent to ensure food safety. In this study, we developed two fluorescent artificial receptor-based sensors via a boronate affinity molecular imprinting strategy targeting E. coli O157:H7. Fluorescein- and rhodamine-grafted artificial receptors were synthesized using bacterial surface glycoproteins and lipopolysaccharides as the molecular-sized templates to create the specific imprinted cavities. The fluorescent sensors can achieve the recognition within 5 min, displaying cross-reactivity factors of 2.6-40.6 (fluorescein) and 1.5-18.4 (rhodamine), and ultra-sensitive detection limits of 7 CFU/mL (fluorescein) and 2 CFU/mL (rhodamine). The fluorescent artificial receptor-based sensors showed spiking recovery rates in the range of 81 %∼101 %, exhibiting high accuracy as the classical plate counting method (71 %∼112 %) in milk and tap water samples. This strategy establishes a universal platform for constructing high-performance fluorescent sensors for rapidly screening pathogenic bacteria in food safety.