Enantiopure Chiral Poly(glycerol methacrylate) Self-Assembled Monolayers Knock Down Protein Adsorption and Cell Adhesion

Authors

  • Zheng Li,

    1. Department of Chemistry, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 4, D-06099 Halle (Saale), Germany
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  • Alexander Köwitsch,

    1. Department of Pharmaceutical Technology and Biopharmacy, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Biomedical Materials Group, D-06099 Halle (Saale), Germany
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  • Guoying Zhou,

    1. Department of Pharmaceutical Technology and Biopharmacy, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Biomedical Materials Group, D-06099 Halle (Saale), Germany
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  • Thomas Groth,

    1. Department of Pharmaceutical Technology and Biopharmacy, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Biomedical Materials Group, D-06099 Halle (Saale), Germany
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  • Bodo Fuhrmann,

    1. Interdisciplinary Center for Materials Research, Martin Luther University Halle-Wittenberg, D-06120 Halle, Germany
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  • Marcus Niepel,

    1. Department of Pharmaceutical Technology and Biopharmacy, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Biomedical Materials Group, D-06099 Halle (Saale), Germany
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  • Elkin Amado,

    1. Department of Chemistry, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 4, D-06099 Halle (Saale), Germany
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  • Jörg Kressler

    Corresponding author
    1. Department of Chemistry, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 4, D-06099 Halle (Saale), Germany
    • Department of Chemistry, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 4, D-06099 Halle (Saale), Germany.
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Abstract

Chirality plays a fundamental role not only in biological systems, but also in synthetic materials intended for bio-applications. Self-assembled monolayers (SAMs) are prepared on gold surfaces through a “grafting to” method from racemic or enantiopure chiral poly(glycerol methacrylate)s (PGMA(rac), PGMA(R), and PGMA(S)), having a thiol endgroup. Such SAMs constitute a chemically and structurally well-defined model substrate for studying protein adsorption and cell adhesion as a function of the polymer chirality. Surface plasmon resonance measurements reveal that PGMA SAMs greatly reduce the adsorption of bovine serum albumin (BSA) compared to bare gold surfaces. Interestingly, enantiopure SAMs based on PGMA(R) or PGMA(S) show a significantly larger reduction in BSA adsorption than PGMA(rac)-covered surfaces. Studies with the monocytic cell line THP-1 show a similar relationship between enantiopurity of PGMA SAMs and the extent of cell adhesion. Ellipsometry and Raman spectroscopy measurements indicate that SAMs formed by PGMA(rac) have a higher grafting density compared to SAMs of PGMA(R) and PGMA(S). This seems to be due to the ability of PGMA(rac) to form more intermolecular hydrogen bonds among polymer chains compared to the enantiopure PGMAs. Circular dichroism spectroscopy provide evidence that enantiopure polymers adopt a chiral ordered conformation, most likely helical, in aqueous solutions. It is concluded that a higher water content of SAMs formed by enantiopure PGMA(S) and PGMA(R) SAMs arises from the macromolecular chiral conformation adopted by their enantiopure PGMA chains, and it is the decisive reason for the reduced BSA adsorption and cell adhesion as compared to PGMA(rac) SAMs.

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