title: Plasmonic ELISA for the ultrasensitive detection of Treponema pallidum.
abstract: In this report, we have developed a plasmonic ELISA strategy for the detection of syphilis. Plasmonic ELISA is an enzyme-linked immunoassay combined with enzyme-mediated surface plasmon resonance (SPR) of gold nanoparticles (AuNPs). Immune response of the Treponema pallidum (T. pallidum) antibodies triggers the acetylcholinesterase-catalyzed hydrolysis of acetylthiocholine to produce abundant thiocholine. The positive charged thiol, in turn, alters the surface charge distribution the AuNPs and leads to the agglomeration of the AuNPs. The induced strong localized SPR effect of the agglomerate AuNPs can, thus, allow the quantitative assay of T. pallidum antibodies due to the remarkable color and absorption spectral response changes of the reaction system. The plasmonic ELISA exhibited a quasilinear response to the logarithmic T. pallidum antibody concentrations in the range of 1pg/mL-10ng/mL with a detection limit of 0.98pg/mL. Such a low detection limit was 1000-fold improvements in sensitivity over a conventional ELISA. The results of plasmonic ELISA in syphilis assays of serum specimens from 60 patients agreed with those obtained using a conventional ELISA method. The plasmonic ELISA has characteristics (analyte specific, cost-effective, ease of automatic, low limit of detection) that provide potential for diagnosis and therapeutic monitoring of syphilis.
authors.affiliation: Clinical Laboratory Centre of the Third Xiangya Hospital, Central South University, Changsha 410013, PR China.
authors.forename: Xin-Min
authors.initials: XM
authors.lastname: Nie
authors.affiliation: Clinical Laboratory Centre of the Third Xiangya Hospital, Central South University, Changsha 410013, PR China.
authors.forename: Rong
authors.initials: R
authors.lastname: Huang
authors.affiliation: Clinical Laboratory Centre of the Third Xiangya Hospital, Central South University, Changsha 410013, PR China.
authors.forename: Cai-Xia
authors.initials: CX
authors.lastname: Dong
authors.affiliation: State Key Laboratory of Chemo/Bio-sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China.
authors.forename: Li-Juan
authors.initials: LJ
authors.lastname: Tang
authors.affiliation: Clinical Laboratory Centre of the Third Xiangya Hospital, Central South University, Changsha 410013, PR China. Electronic address: aguirong@163.com.
authors.forename: Rong
authors.initials: R
authors.lastname: Gui
authors.affiliation: State Key Laboratory of Chemo/Bio-sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China. Electronic address: jianhuijiang@hnu.edu.cn.
authors.forename: Jian-Hui
authors.initials: JH
authors.lastname: Jiang
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D015374:Biosensing Techniques / Q000295:instrumentation; D004797:Enzyme-Linked Immunosorbent Assay / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation*; D020349:Surface Plasmon Resonance / Q000295:instrumentation*; D013587:Syphilis / Q000097:blood / Q000175:diagnosis* / Q000382:microbiology*; D014210:Treponema pallidum / Q000276:immunology / Q000302:isolation & purification*
chemical_list: D000907:Antibodies, Bacterial
keywords: Enzyme-linked immunosorbent assay; Gold nanoparticles; Surface plasmon resonance; Syphilis; Treponema pallidum