title: Direct competitive chemiluminescence immunoassays based on gold-coated magnetic particles for detection of chloramphenicol.
abstract: Direct competitive chemiluminescence immunoassays (CLIA) based on gold-coated magnetic nanospheres (Au-MNPs) were developed for rapid analysis of chloramphenicol (CAP). The Au-MNPs were modified with carboxyl groups and amino groups by 11-mercaptoundecanoic acid (MUA) and cysteamine respectively, and then were respectively conjugated with CAP base and CAP succinate via an activating reaction using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS). NSP-DMAE-NHS, a new and effective luminescence reagent, was employed to label anti-CAP antibody (mAb) as a tracer in direct CLIA for CAP detection using a 'homemade' luminescent measurement system that was set up with a photomultiplier tube (PMT) and a photon counting unit linked to a computer. The sensitivities and limits of detection (LODs) of the two methods were obtained and compared according to the inhibition curves. The 50% inhibition concentration (IC50 ) values of the two methods were about 0.044 ng/mL and 0.072 ng/mL respectively and LODs were approximately 0.001 ng/mL and 0.006 ng/mL respectively. To our knowledge, they were much more sensitive than any traditional enzyme-linked immunosorbent assay (ELISA) ever reported. Moreover, the new luminescence reagent NSP-DMAE-NHS is much more sensitive and stable than luminol and its derivatives, contributing to the sensitivity enhancement.
authors.affiliation: School of Science, Xi'an Jiaotong University, Xi'an, People's Republic of China.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Liang
authors.affiliation: School of Science, Xi'an Jiaotong University, Xi'an, People's Republic of China.
authors.forename: Xiangyi
authors.initials: X
authors.lastname: Fang
authors.affiliation: Tongji University, Shanghai, People's Republic of China.
authors.forename: Manwen
authors.initials: M
authors.lastname: Yao
authors.affiliation: Department of Clinical Laboratory The First Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an, People's Republic of China.
authors.forename: Yucong
authors.initials: Y
authors.lastname: Yang
authors.affiliation: School of Science, Xi'an Jiaotong University, Xi'an, People's Republic of China.
authors.forename: Junfeng
authors.initials: J
authors.lastname: Li
authors.affiliation: School of Electronic and Information Engineering, Xi'an Jiaotong University, Xi'an, People's Republic of China.
authors.forename: Hongjun
authors.initials: H
authors.lastname: Liu
authors.affiliation: School of Electronic and Information Engineering, Xi'an Jiaotong University, Xi'an, People's Republic of China.
authors.forename: Linyu
authors.initials: L
authors.lastname: Wang
mesh_terms: D002701:Chloramphenicol / Q000032:analysis*; D006046:Gold / Q000737:chemistry*; D007118:Immunoassay; D049449:Luminescence; D058185:Magnetite Nanoparticles / Q000737:chemistry*
chemical_list: D058185:Magnetite Nanoparticles; D002701:Chloramphenicol; D006046:Gold
keywords: CAP detection; NSP-DMAE-NHS; chemiluminescent immunoassays (CLIA); gold-coated magnetic nanoparticles (Au-MNPs)