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Issue 5, 2018
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Integrated dual-modality microfluidic sensor for biomarker detection using lithographic plasmonic crystal

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Abstract

This paper reports an integrated dual-modality microfluidic sensor chip, consisting of a patterned periodic array of nanoposts coated with gold (Au) and graphene oxide (GO), to detect target biomarker molecules in a limited sample volume. The device generates both electrochemical and surface plasmon resonance (SPR) signals from a single sensing area of Au–GO nanoposts. The Au–GO nanoposts are functionalized with specific receptor molecules, serving as a spatially well-defined nanostructured working electrode for electrochemical sensing, as well as a nanostructured plasmonic crystal for SPR-based sensing via the excitation of surface plasmon polaritons. High sensitivity of the electrochemical measurement originates from the presence of the nanoposts on the surface of the working electrode where radial diffusion of redox species occurs. Complementarily, the SPR detection allows convenient tracking of dynamic antigen–antibody interactions, to describe the association and dissociation phases occurring at the sensor surface. The soft-lithographically formed nanoposts provide high reproducibility of the sensor response to epidermal growth factor receptor (ErbB2) molecules even at a femtomolar level. Sensitivities of the electrochemical measurements to ErbB2 are found to be 20.47 μA μM−1 cm−2 in a range from 1 fM to 0.1 μM, and those of the SPR measurements to be 1.35 nm μM−1 in a range from 10 pM to 1 nM, and 0.80 nm μM−1 in a range from 1 nM to 0.1 μM. The integrated dual-modality sensor offers higher sensitivity (through higher surface area and diffusions from nanoposts for electrochemical measurements), as well as the dynamic measurements of antigen–antibody bindings (through the SPR measurement), while operating simultaneously in a same sensing area using the same sample volume.

Graphical abstract: Integrated dual-modality microfluidic sensor for biomarker detection using lithographic plasmonic crystal

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Publication details

The article was received on 12 Nov 2017, accepted on 08 Feb 2018 and first published on 08 Feb 2018


Article type: Paper
DOI: 10.1039/C7LC01211J
Citation: Lab Chip, 2018,18, 803-817
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    Integrated dual-modality microfluidic sensor for biomarker detection using lithographic plasmonic crystal

    Md. A. Ali, S. Tabassum, Q. Wang, Y. Wang, R. Kumar and L. Dong, Lab Chip, 2018, 18, 803
    DOI: 10.1039/C7LC01211J

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