Salmonella detection using 16S ribosomal DNA/RNA probe-gold nanoparticles and lateral flow immunoassay.

An ultrasensitive, simple, and fast lateral flow immunoassay for Salmonella detection using gold nanoparticles conjugated with a DNA probe, which is complementary to the 16S ribosomal RNA and DNA of Salmonella, has been developed. The detection limit is 5 fmol for the synthetic single-stranded DNA. For the Salmonella cultured samples, the nucleic acids from 10(7) bacteria were rapidly detected in 30 min. After silver enhancement, the detection limit was as low as 10(4) cells which is lower than 10(5) bacteria cells, the human infective dose of food-borne Salmonella. Furthermore, the probes used in this study are specific to Salmonella compared to several other Enterobacteriaceae. This approach would be a useful tool for microbial detection regarding food safety or clinical diagnosis. It is also suitable for large-scale screening in developing countries because it is low-cost, sensitive, specific and convenient.