A chemiluminescent aptasensor based on rolling circle amplification and Co/N-(aminobutyl)-N-(ethylisoluminol) functional flowerlike gold nanoparticles for Salmonella typhimurium detection.

A sensitive steady-state chemiluminescent aptasensor based on rolling circle amplification (RCA) was fabricated for the detection of Salmonella typhimurium. The sensor utilized aptamer modified FeO magnetic nanoparticles (MNPs) as capture probes, aptamer as recognition molecules, and Co enhanced N‑(aminobutyl)-N-(ethylisoluminol) (ABEI) functional flowerlike gold nanoparticles (AuNFs) and complementary strand (cDNA) complex (Co/ABEI-AuNFs-cDNA) as signal probes. And P-Iodophenol (PIP) was also added to form a typical ABEI- AuNFs-PIP-HO steady-state CL system. By virtue of FeO MNPs based solid-phase RCA strategy, S. typhimurium can be first captured by the aptamer immobilized on the surface of FeO MNPs then complex with RCA products to form a sandwich complex. Co/ABEI-AuNFs-cDNA signal probes were then assembled on the RCA products to produce and enhance CL signals. Under optimal conditions, the logarithmic correlation between the concentration of S. typhimurium and the CL signal was found to be linear within the range of 32cfumL to 3.2×10cfumL (R =0.9921). The limits of detection of the developed method were found to be 10cfumL for S. typhimurium. The method was also used to detect S. typhimurium in real pork samples. The results were compared with those obtained from the plate-counting methods and showed good consistency. Therefore, this detection aptasnesor can be a good candidate for sensitive and selective detection of S. typhimurium with simple and effective operations.