title: Ultrasensitive chemiluminescent immunoassay of Salmonella with silver enhancement of nanogold labels.
abstract: In this paper, silver enhancement of nanogold labels coupled with chemiluminescence detection was developed for ultrasensitive immunoassay of Salmonella based upon antigen-antibody immunoreaction. Polyclonal rabbit anti-Salmonella sp. antibodies (pAb) were employed to establish the analytical protocol. The pAb coated onto ELISA microwell plates and Au nanoparticles (Au NPs) conjugated pAb capture target Salmonella to form a sandwich-type complex. Silver then was in situ deposited around the Au NPs core and resulted in the signal amplification. In consequence, silver was dissolved to form Ag(+) and a sensitive chemiluminescence based on the Ag(+)-K2S2O8-Mn(2+)-luminol system was coupled for further signal amplification. Under the optimized conditions, the chemiluminescent intensity is proportional to target Salmonella over the range of 5-1038 cfu mL(-1) with a detection limit of 5 cfu mL(-1). The relative standard deviation for 11 measurements of about 50-100 cfu/mL target Salmonella is 4.7%. The proposed method was successfully applied to measure Salmonella in food samples and the results are identical to those of the offical standard method of China. These offer us a more powerful tool for ultrasensitive assay of foodborne pathogens.
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China. wangzp1974@hotmail.com
authors.forename: Zhouping
authors.initials: Z
authors.lastname: Wang
authors.forename: Nuo
authors.initials: N
authors.lastname: Duan
authors.forename: Jingquan
authors.initials: J
authors.lastname: Li
authors.forename: Jing
authors.initials: J
authors.lastname: Ye
authors.forename: Shufeng
authors.initials: S
authors.lastname: Ma
authors.forename: Guowei
authors.initials: G
authors.lastname: Le
mesh_terms: D000937:Antigen-Antibody Reactions; D006046:Gold / Q000737:chemistry*; D007118:Immunoassay; D049449:Luminescence; D053768:Metal Nanoparticles / Q000737:chemistry*; D012475:Salmonella / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*
chemical_list: D012834:Silver; D006046:Gold