Facile Preparation of a Bacteria Imprinted Artificial Receptor for Highly Selective Bacterial Recognition and Label-Free Impedimetric Detection.

The effective identification and quantification of pathogenic bacteria is essential for addressing serious public health issues. Here, we demonstrate a simple and universal impedimetric sensor for highly selective and sensitive detection of pathogenic bacteria based on the recognition by a bacteria-imprinted polypyrrole (BIP) film. The BIP film was facilely prepared via one-step electro-polymerization followed by in situ removal of the bacterial template. The film structure is novel with noncavity-like imprinted sites situated at the surface of the polypyrrole (PPy) matrix, which are more accessible for the target bacteria and should enhance the mass transfer and the binding kinetics. A limit of quantitation low to 103 CFU/mL was achieved within 1 h for the detection of E. coli O157:H7, which is comparable to the antibody-based assays. Moreover, the sensor displayed remarkable selectivity, especially regarding the specific identification of bacterial serotypes. When employed to analyze E. coli O157:H7 in real drinking water, apple juice, and milk samples, the sensor showed recoveries from 96.0% to 107.9% with relative standard derivations (RSDs) less than 4%. The BIP-based sensing strategy provides a universal approach for specific, selective, and rapid detection of pathogenic bacteria. As compared to conventional biosensors based on biomolecular recognition, this sensor shows clear advantages including easy-of-preparation, robustness, and low cost, which may hold great potential in fields of food/public safety monitoring.