Sensitive and simultaneous detection of different pathogens by surface-enhanced Raman scattering based on aptamer and Raman reporter co-mediated gold tags

A biosensor based on novel SERS tags, consisting of gold nanorods (GNRs) complexed with oligonucleotide aptamers and the Raman reporters, was developed for the sensitive and simultaneous detection of different food pathogens. The aptamers not only act as bio-recognition molecules, but along with the Raman reporters, induce the GNRs to grow to specific shapes, which in turn enhance the Raman signal and facilitate sensitive detection. Signal interference during the simultaneous detection of pathogens is avoided, due to the stable anchored aptamers and embedded Raman reporters. We combined the novel SERS tags with antibody-modified magnetic nanoparticles to create a biosensor capable of simultaneous detection of Escherichia coli O157:H7 and Salmonella typhimurium with good linear response (10(1) to 10(6) cfu/mL), high detection sensitivity (< 8 cfu/mL) and recovery rate (95.26-107.88%) in spiked food samples. This strategy achieves the goal of sensitive and simultaneous quantitative detection of pathogens.