Electroaddressing of Cell Populations by Co-Deposition with Calcium Alginate Hydrogels

Authors

  • Xiao-Wen Shi,

    1. Center for Biosystems Research University of Maryland Biotechnology Institute 5115 Plant Sciences Building College Park, MD 20742 (USA)
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  • Chen-Yu Tsao,

    1. Center for Biosystems Research University of Maryland Biotechnology Institute 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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  • Xiaohua Yang,

    1. Center for Biosystems Research University of Maryland Biotechnology Institute 5115 Plant Sciences Building College Park, MD 20742 (USA)
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  • Yi Liu,

    1. Center for Biosystems Research University of Maryland Biotechnology Institute 5115 Plant Sciences Building College Park, MD 20742 (USA)
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  • Peter Dykstra,

    1. Department of Electrical and Computer Engineering University of Maryland College Park, MD, 20742 (USA)
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  • Gary W. Rubloff,

    1. Department of Materials Science and Engineering University of Maryland College Park, MD, 20742 (USA)
    2. Institute for Systems Research University of Maryland College Park, MD, 20742 (USA)
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  • Reza Ghodssi,

    1. Department of Electrical and Computer Engineering University of Maryland College Park, MD, 20742 (USA)
    2. Institute for Systems Research University of Maryland College Park, MD, 20742 (USA)
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  • William E. Bentley,

    1. Center for Biosystems Research University of Maryland Biotechnology Institute 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 Biotechnology Institute 5115 Plant Sciences Building College Park, MD 20742 (USA)
    • Center for Biosystems Research University of Maryland Biotechnology Institute 5115 Plant Sciences Building College Park, MD 20742 (USA).
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Abstract

Electroaddressing of biological components at specific device addresses is attractive because it enlists the capabilities of electronics to provide spatiotemporally controlled electrical signals. Here, the electrodeposition of calcium alginate hydrogels at specific electrode addresses is reported. The method employs the low pH generated at the anode to locally solubilize calcium ions from insoluble calcium carbonate. The solubilized Ca2+ can then bind alginate to induce this polysaccharide to undergo a localized sol-gel transition. Calcium alginate gel formation is shown to be spatially controlled in the normal and lateral dimensions. The deposition method is sufficiently benign that it can be used to entrap the bacteria E. coli. The entrapped cells are able to grow and respond to chemical inducers in their environment. Also, the entrapped cells can be liberated from the gel network by adding sodium citrate that can compete with alginate for Ca2+ binding. The capabilities of calcium alginate electrodeposition is illustrated by entrapping reporter cells that can recognize the quorum sensing autoinducer 2 (AI-2) signaling molecule. These reporter cells were observed to recognize and respond to AI-2 generated from an external bacterial population. Thus, calcium alginate electrodeposition provides a programmable method for the spatiotemporally controllable assembly of cell populations for cell-based biosensing and for studying cell-cell signaling.

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