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Reversible Electroaddressing of Self-assembling Amino-Acid Conjugates

Authors

  • Yi Liu,

    1. Center for Biosystems Research, University of Maryland, 5115 Plant Sciences Building, College Park, MD 20742, USA
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  • Eunkyoung Kim,

    1. Center for Biosystems Research, University of Maryland, 5115 Plant Sciences Building, College Park, MD 20742, USA
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  • Rein V. Ulijn,

    1. WestCHEM Department of Pure and Applied Chemistry, The University of Strathclyde, 295 Cathedral Street, Glasgow G1 1XL, Scotland, UK
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  • William E. Bentley,

    1. Center for Biosystems Research, University of Maryland, 5115 Plant Sciences Building, College Park, MD 20742, USA
    2. Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
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  • Gregory F. Payne

    Corresponding author
    1. Center for Biosystems Research, University of Maryland, 5115 Plant Sciences Building, College Park, MD 20742, USA
    2. Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
    • Center for Biosystems Research, University of Maryland, 5115 Plant Sciences Building, College Park, MD 20742, USA.
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Abstract

The triggered assembly of organic and biological materials in response to imposed electrical signals (i.e., electroaddressing) provides interesting opportunities for applications in molecular electronics, biosensing and nanobiotechnology. Recent studies have shown that the conjugation of aromatic moieties to short peptides often yields hydrogelator compounds that can be triggered to self-assemble over a hierarchy of length scales in response to a reduction in pH. Here, we examined the capabilities of fluorenyl-9-methoxycarbonyl-phenylalanine (Fmoc-Phe) to electrodeposit in response to an electrochemically-induced pH gradient generated at the anode surface. We report that the electrodeposition of Fmoc-Phe; is rapid (minutes), can be spatially controlled in normal and lateral directions, and can be reversed by applying a brief cathodic current. Further more, we show that Fmoc-Phe can be simultaneously deposited on one electrode address (anode) while it is being cathodically stripped from a separate electrode address of the same chip. Finally, we demonstrate that these capabilities can be extended for electroaddressing within microfluidic channels. The reversible assembly/disassembly of molecular gelators (Fmoc-amino acids and Fmoc-peptides) in response to spatiotemporally imposed electrical signals offers unique opportunities for electroaddressing that should be especially valuable for lab-on-a-chip applications.

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