Interference-free determination of ischemia-modified albumin using quantum dot coupled X-ray fluorescence spectroscopy

    Authors

    Y. Luo; C. M. Wang; T. L. Jiang; B. Zhang; J. F. Huang; P. Liao;W. L. Fu

    Comments

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    Abbreviated Journal Title

    Biosens. Bioelectron.

    Keywords

    Albumin cobalt binding; Ischemic heart disease; Ischemia-modified; protein; Quantum dots; X-ray fluorescence; MYOCARDIAL-ISCHEMIA; SERUM-ALBUMIN; EMERGENCY-DEPARTMENT; HEART-DISEASE; TROPONIN-T; INFARCTION; BINDING; COBALT; MARKER; ASSAY; Biophysics; Biotechnology & Applied Microbiology; Chemistry, Analytical; Electrochemistry; Nanoscience & Nanotechnology

    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 30 min 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 (7 mg/L), triglyceride (5.2 mg/L), IgG (10 g/L), and fibrinogen (4 g/L). A linearity of 1-100 mg/mL is obtained in iHSA determination using XRF (r(2)=0.979). The proposed Q-XRF assay demonstrates a lowest detection limit of 0.05 U/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 792 U/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. (C) 2013 Elsevier B.V. All rights reserved.

    Journal Title

    Biosensors & Bioelectronics

    Volume

    51

    Publication Date

    1-1-2014

    Document Type

    Article

    Language

    English

    First Page

    136

    Last Page

    142

    WOS Identifier

    WOS:000326905500019

    ISSN

    0956-5663

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