title: Sandwich-format electrochemiluminescence assays for tumor marker based on PAMAM dendrimer-L-cysteine-hollow gold nanosphere nanocomposites.
abstract: In this work, a novel polyamidoamine (PAMAM) dendrimer-L-cysteine-hollow gold nanospheres nanocomposite was fabricated and used as the promoter for the peroxydisulfate/O2 ECL system to detect the concentration of the tumor marker carcinoembryonic antigen (CEA). Herein, the carboxyl-terminated PAMAM dendrimers were decorated with L-cysteine (L-Cys) by EDC/NHS coupling chemistry. Then, the hollow gold nanospheres (HGNPs) were employed as effective nano-carriers for the assembly of PAMAM-L-Cys via thiols-Au bonding, which was used for further loading of detection antibody (Ab2) to form the PAMAM-L-Cys-HGNPs-Ab2 bioconjugates. In the presence of target CEA, the sandwiched immuno-structure can be formed between the capture anti-CEA antibodies (Ab1), which self-assembled on deposited gold modified electrode, and the Ab2 on the PAMAM-L-Cys-HGNPs, thereby resulting in a proportional increase in ECL response, due to the significant enhancement of PAMAM-L-Cys-HGNPs toward peroxydisulfate/O2 ECL system. As a result, a sandwich ECL assay for CEA detection was developed with excellent sensitivity of a large concentration variation from 20 fg/mL to 1.0 ng/mL and a detection limit of 6.7 fg mL(-1).
authors.affiliation: Key Laboratory on Luminescence and Real-Time Analysis, Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China. Electronic address: yingzhuo@swu.edu.cn.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhuo
authors.forename: Guofeng
authors.initials: G
authors.lastname: Gui
authors.forename: Yaqin
authors.initials: Y
authors.lastname: Chai
authors.forename: Ni
authors.initials: N
authors.lastname: Liao
authors.forename: Kai
authors.initials: K
authors.lastname: Xiao
authors.forename: Ruo
authors.initials: R
authors.lastname: Yuan
mesh_terms: D014408:Biomarkers, Tumor / Q000737:chemistry / Q000302:isolation & purification*; D015374:Biosensing Techniques / Q000379:methods*; D002272:Carcinoembryonic Antigen / Q000302:isolation & purification*; D003545:Cysteine / Q000737:chemistry; D050091:Dendrimers / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry; D053761:Nanocomposites / Q000737:chemistry; D054118:Nanospheres / Q000737:chemistry; D009369:Neoplasms / Q000175:diagnosis*
chemical_list: D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen; D050091:Dendrimers; C104700:PAMAM Starburst; D006046:Gold; D003545:Cysteine
keywords: CEA; ECL immunosensor; PAMAM dendrimer; Peroxydisulfate; l-Cysteine