title: A sandwich immunoassay for detection of Aβ(1-42) based on quantum dots.
abstract: Alzheimer's disease (AD) is the primary cause of dementia over the age of 60, affecting more than 35 million people worldwide. Methods for early diagnosis of AD are critical for the development of effective treatments to combat this debilitating disease. It was confirmed that amyloid-beta peptide 1-42 (Aβ(1-42)) is the biomarker of its early diagnosis. In this work, we present a new sandwich immunoassay method for the detection of Aβ(1-42) based on quantum dot (QDs) nanolabels and magnetic separation. In the presence of Aβ(1-42), QDs linked to magnetic beads (MB) via the formation of immune-sandwich complex and can be removed by a magnetic field. And as a result, fluorescence intensity from QDs in the supernatant decreased. Under the optimized conditions, there is a linear relationship between the fluorescence intensity of supernatant solution and the concentration of Aβ(1-42) from 0.50 to 8.0 nM with a limit detection of 0.2 nM (3σ). This immunoassay was applied to detect Aβ(1-42) in human cerebrospinal fluid (CSF) successfully.
authors.affiliation: Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
authors.forename: Jiangli
authors.initials: J
authors.lastname: Pi
authors.affiliation: Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
authors.forename: Yijuan
authors.initials: Y
authors.lastname: Long
authors.affiliation: Department of Neurosurgery, the Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, PR China.
authors.forename: Ning
authors.initials: N
authors.lastname: Huang
authors.affiliation: Department of Neurosurgery, the Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, PR China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Cheng
authors.affiliation: Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China. Electronic address: zhenghz@swu.edu.cn.
authors.forename: Huzhi
authors.initials: H
authors.lastname: Zheng
mesh_terms: D016229:Amyloid beta-Peptides / Q000032:analysis* / Q000134:cerebrospinal fluid; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D057230:Limit of Detection; D010446:Peptide Fragments / Q000032:analysis* / Q000134:cerebrospinal fluid; D045663:Quantum Dots / Q000737:chemistry*
chemical_list: D016229:Amyloid beta-Peptides; D010446:Peptide Fragments; C075222:amyloid beta-protein (1-42)
keywords: Alzheimer’s disease; Amyloid-beta peptide; Magnetic beads; Quantum dots; Sandwich immunoassay