Arrangement of type IV collagen on NH2 and COOH functionalized surfaces

Authors

  • Nuno Miranda Coelho,

    1. Institut de Bioenginyeria de Catalunya, Barcelona, Spain
    2. Universitat Politècnica de Catalunya, Barcelona, Spain
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  • Cristina González-García,

    1. CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Valencia, Spain
    2. Center for Biomaterials and Tissue Engineering, Universidad Politécnica de Valencia, Valencia, Spain
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  • Manuel Salmerón-Sánchez,

    1. CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Valencia, Spain
    2. Center for Biomaterials and Tissue Engineering, Universidad Politécnica de Valencia, Valencia, Spain
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  • George Altankov

    Corresponding author
    1. Institut de Bioenginyeria de Catalunya, Barcelona, Spain
    2. CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Valencia, Spain
    3. ICREA (Institució Catalana de Recerca i Estudis Avançats), Catalonia, Spain; telephone: +34 934 039 709; fax: +34 934 039 873
    • Institut de Bioenginyeria de Catalunya, Barcelona, Spain.
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Abstract

Apart from the paradigm that cell–biomaterials interaction depends on the adsorption of soluble adhesive proteins we anticipate that upon distinct conditions also other, less soluble ECM proteins such as collagens, associate with the biomaterials interface with consequences for cellular response that might be of significant bioengineering interest. Using atomic force microscopy (AFM) we seek to follow the nanoscale behavior of adsorbed type IV collagen (Col IV)—a unique multifunctional matrix protein involved in the organization of basement membranes (BMs) including vascular ones. We have previously shown that substratum wettability significantly affects Col IV adsorption pattern, and in turn alters endothelial cells interaction. Here we introduce two new model surfaces based on self-assembled monolayers (SAMs), a positively charged –NH2, and negatively charged –COOH surface, to learn more about their particular effect on Col IV behavior. AFM studies revealed distinct pattern of Col IV assembly onto the two SAMs resembling different aspects of network-like structure or aggregates (suggesting altered protein conformation). Moreover, the amount of adsorbed FITC-labeled Col IV was quantified and showed about twice more protein on NH2 substrata. Human umbilical vein endothelial cells attached less efficiently to Col IV adsorbed on negatively charged COOH surface judged by altered cell spreading, focal adhesions formation, and actin cytoskeleton development. Immunofluorescence studies also revealed better Col IV recognition by both α1 and α2 integrins on positively charged NH2 substrata resulting in higher phosphorylated focal adhesion kinase recruitment in the focal adhesion complexes. On COOH surface, no integrin clustering was observed. Taken altogether these results, point to the possibility that combined NH2 and Col IV functionalization may support endothelization of cardiovascular implants. Biotechnol. Bioeng. 2011;108: 3009–3018. © 2011 Wiley Periodicals, Inc.

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