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Issue 47, 2012
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3d localization and diffusion of proteins in polyelectrolyte multilayers

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Abstract

The interaction of diverse biomaterials with surfaces is more crucial than ever for biomedical applications to ensure efficiency and reproducibility. Very interesting surface materials are micrometer-thick polyelectrolyte multilayers. Not only their surface but also the bulk can be loaded with biomaterials like proteins or DNA for various purposes. Therefore, we established a method to analyze the lateral and vertical distribution of fluorescently labelled proteins of various size and charge in polyelectrolyte films composed of poly(L-lysine) and hyaluronic acid by confocal laser scanning microscopy. This approach enables us to measure the diffusion coefficients of the proteins via fluorescence recovery after photobleaching as a function of their vertical position in the film and facilitates the understanding of molecular interactions in the film with a high resolution in both space and time. As a result, we confirm that protein loading in the film is driven by electrostatic interactions – uncharged dextran molecules of 10 and 500 kDa do not diffuse into the film. Proteins of different sizes (3–11 nm) can diffuse relatively fast (D = 2–4 μm2 s−1) independent of their net charge, indicating complex interpolymer interactions. This approach is a new powerful experimental tool to design the polyelectrolyte multilayers for bio-applications by finding a relationship between intermolecular interactions and mobility and availability of biomolecules to biological samples (e.g. cells) or detection units (e.g. biosensors).

Graphical abstract: 3d localization and diffusion of proteins in polyelectrolyte multilayers

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Publication details

The article was received on 28 Jun 2012, accepted on 11 Oct 2012 and first published on 25 Oct 2012


Article type: Communication
DOI: 10.1039/C2SM26500A
Soft Matter, 2012,8, 11786-11789

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    3d localization and diffusion of proteins in polyelectrolyte multilayers

    K. Uhlig, N. Madaboosi, S. Schmidt, M. S. Jäger, J. Rose, C. Duschl and D. V. Volodkin, Soft Matter, 2012, 8, 11786
    DOI: 10.1039/C2SM26500A

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