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Issue 22, 2011
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Preconcentration and detection of the phosphorylated forms of cardiac troponin I in a cascade microchip by cationic isotachophoresis

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Abstract

This paper describes the detection of a cardiac biomarker, cardiac troponin I (cTnI), spiked into depleted human serum using cationic isotachophoresis (ITP) in a 3.9 cm long poly(methyl methacrylate) (PMMA) microfluidic channel. The microfluidic chip incorporates a 100× cross-sectional area reduction, including a 10× depth reduction and a 10× width reduction, to increase sensitivity during ITP. The cross-sectional area reductions in combination with ITP allowed visualization of lower concentrations of fluorescently labeled cTnI. ITP was performed in both “peak mode” and “plateau mode” and the final concentrations obtained were linear with initial cTnI concentration. We were able to detect and quantify cTnI at initial concentrations as low as 46 ng mL−1 in the presence of human serum proteins and obtain cTnI concentrations factors as high as ∼ 9000. In addition, preliminary ITP experiments including both labeled cTnI and labeled protein kinase A (PKA) phosphorylated cTnI were performed to visualize ITP migration of different phosphorylated forms of cTnI. The different phosphorylated states of cTnI formed distinct ITP zones between the leading and terminating electrolytes. To our knowledge, this is the first attempt at using ITP in a cascade microchip to quantify cTnI in human serum and detect different phosphorylated forms.

Graphical abstract: Preconcentration and detection of the phosphorylated forms of cardiac troponin I in a cascade microchip by cationic isotachophoresis

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Publication details

The article was received on 31 May 2011, accepted on 25 Aug 2011 and first published on 21 Sep 2011


Article type: Paper
DOI: 10.1039/C1LC20469F
Citation: Lab Chip, 2011,11, 3793-3801
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    Preconcentration and detection of the phosphorylated forms of cardiac troponin I in a cascade microchip by cationic isotachophoresis

    D. Bottenus, M. R. Hossan, Y. Ouyang, W. Dong, P. Dutta and C. F. Ivory, Lab Chip, 2011, 11, 3793
    DOI: 10.1039/C1LC20469F

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