Title

Interference-Free Determination Of Ischemia-Modified Albumin Using Quantum Dot Coupled X-Ray Fluorescence Spectroscopy

Keywords

Albumin cobalt binding; Ischemia-modified protein; Ischemic heart disease; Quantum dots; X-ray fluorescence

Abstract

Ischemia-modified protein (IMA) is the most sensitive diagnostic biomarker of ischemic heart disease, but differentiation of IMA from human serum albumin (HSA), a ubiquitous serum protein, is still challenging owing to the shared antigenicity. In this investigation, we developed a rapid and interference-free approach for IMA determination using quantum dots-coupled X-ray Fluorescence Spectroscopy (Q-XRF). In a typical Q-XRF assay, serum total HSA is quantified using quantum dot-coupled sandwich immunoassay, and intact HSA (iHSA) is determined using a XRF spectroscopy, by measuring XRF intensity of Co (II) bonded to iHSA. IMA concentration is automatically determined within 30min by calculating the difference between total HSA and iHSA. This strategy can effectively eliminate the interference from native HSA level. Results show that no significant influences have been observed from hemolysis or high levels of cholesterol (7mg/L), triglyceride (5.2mg/L), IgG (10g/L), and fibrinogen (4g/L). A linearity of 1-100mg/mL is obtained in iHSA determination using XRF (r2=0.979). The proposed Q-XRF assay demonstrates a lowest detection limit of 0.05U/mL. Receiver-operating characteristic (ROC) curves reveal that Q-XRF assay provide an improved sensitivity than ACB assay (95.9% vs. 82.9%) in differentiating ischemic patients from health individuals, at an optimal cutoff point of 79.2U/mL. The proposed approach provides a new strategy for interference-free, simple and rapid evaluation of IMA concentration by combining sandwich immunoassay and XRF spectroscopy. © 2013 Elsevier B.V.

Publication Date

1-5-2014

Publication Title

Biosensors and Bioelectronics

Volume

51

Number of Pages

136-142

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1016/j.bios.2013.07.046

Socpus ID

84882771538 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/84882771538

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