Metal sulfide quantum dots-aggregated PAMAM dendrimer for cadmium ion-selective electrode-based immunoassay of alpha-fetoprotein

• 来源期刊: 中国科学:化学（英文版）
• 年，卷（期）: 2018,（6）
• 页码范围: 750-756
• 页数: 7页
• 语种: 英文

摘要

An ion-selective electrode (ISE) -based immunoassay has been innovatively designed for the sensitive detection of liver cancer biomarker (alpha-fetoprotein, AFP), using metal sulfide quantum dot (QD) -based nano labels.Cd S QDs-aggregated PAMAM dendrimer (QD-DE) was first synthesized and functionalized with polyclonal rabbit anti-human AFP antibodies.Thereafter, a sandwich immunoreaction was implemented on monoclonal mouse anti-human AFP antibody-coated microplate by using antibody-functionalized QD-DE as the secondary antibody.Accompanying the immunocomplex, subsequent potentiometric detection of cadmium ion dissolved from the QD-DE under acidic condition was conducted on a portable cadmium ion-selective electrode (Cd-ISE) .Results revealed that the electrode potential of the Cd-ISE increased with the increment of AFP concentration from 0.1 to 100 ng m L-1 at a detection limit (LOD) of 68 pg m L-1 .The relative standard deviations (RSD) were below9.09％and 10.54％for the intra-and inter-assay, respectively.Additionally, six human serum specimens were determined on CdISE-based immunosensor by using commercial human AFP ELISA kit as the reference, and gave good relationship between two methods.Importantly, Cd-ISE-based immunoassay offers the promise for simple and cost-effective screening of disease-related biomarkers.