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Issue 33, 2017
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Frequency-selective electrokinetic enrichment of biomolecules in physiological media based on electrical double-layer polarization

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Abstract

Proteomic biomarkers of interest to the early diagnosis of diseases and infections are present at trace levels versus interfering species. Hence, their selective enrichment is needed within bio-assays for speeding binding kinetics with receptors and for reducing signal interferences. While DC fields can separate biomolecules based on their electrokinetic mobilities, they are unable to selectively enrich biomarkers versus interfering species, which may possess like-charges. We present the utilization of AC electrokinetics to enable frequency-selective enrichment of nanocolloidal biomolecules, based on the characteristic time constant for polarization of their electrical double-layer, since surface conduction in their ion cloud depends on colloidal size, shape and surface charge. In this manner, using DC-offset AC fields, differences in frequency dispersion for negative dielectrophoresis are balanced against electrophoresis in a nanoslit channel to enable the selective enrichment of prostate specific antigen (PSA) versus anti-mouse immunoglobulin antibodies that cause signal interferences to immunoassays. Through coupling enrichment to capture by receptors on graphene-modified surfaces, we demonstrate the elimination of false positives caused by anti-mouse immunoglobulin antibodies to the PSA immunoassay.

Graphical abstract: Frequency-selective electrokinetic enrichment of biomolecules in physiological media based on electrical double-layer polarization

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Publication details

The article was received on 04 Apr 2017, accepted on 31 Jul 2017 and first published on 03 Aug 2017


Article type: Paper
DOI: 10.1039/C7NR02376F
Citation: Nanoscale, 2017,9, 12124-12131
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    Frequency-selective electrokinetic enrichment of biomolecules in physiological media based on electrical double-layer polarization

    A. Rohani, B. J. Sanghavi, A. Salahi, K. Liao, C. Chou and N. S. Swami, Nanoscale, 2017, 9, 12124
    DOI: 10.1039/C7NR02376F

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