AVS 50th International Symposium
    Biomaterial Interfaces Tuesday Sessions
       Session BI-TuM

Paper BI-TuM2
Mechanical and Biochemical Analyses of Cell Adhesion Strengthening Using Micropatterned Substrates

Tuesday, November 4, 2003, 8:40 am, Room 307

Session: Cell/Surface Interactions
Presenter: N.D. Gallant, Georgia Institute of Technology
Authors: N.D. Gallant, Georgia Institute of Technology
A.J. García, Georgia Institute of Technology
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Cell adhesion to fibronectin (FN) involves integrin binding and subsequent adhesion strengthening, which includes integrin clustering, interactions with cytoskeletal and signaling components to form focal adhesions (FA), and cell spreading. We applied micropatterning methods to control FA size and position to analyze the contributions of FA assembly to adhesion strength. Microcontact printing was used to pattern alkanethiol self-assembled monolayers into arrays of circular adhesive islands (2, 5, 10, 20 µm dia) with a non-adhesive background.@footnote1@ NIH3T3 fibroblasts adhered to FN-coated islands and remained constrained to the patterns presenting a nearly spherical morphology. Cells assembled robust adhesive structures that localized to the micropatterned islands and contained typical components of FA. Cell adhesion strength to FN-coated micropatterned islands was quantified using a spinning disk device that applies a well-defined range of hydrodynamic forces to adherent cells.@footnote2@ Adhesion strength exhibited significant time- and adhesive area-dependent increases. Comparison of experiments for equivalent contact areas showed a 9-fold increase in adhesion strength over time, independent of cell spreading. Bound integrins were quantified using a cross-linking/extraction/reversal biochemical technique.@footnote3@ Significant area dependence was also seen in integrin binding on micropatterned substrates and a correlation between increasing integrin binding and adhesion strength was observed. These results demonstrate that FA assembly, independently of changes in cell morphology, contributes significantly to adhesion strengthening. This work provides an experimental framework for the functional analysis of FA components in adhesive interactions. @FootnoteText@ @footnote 1@N.D. Gallant et al., Langmuir 18, 5579-5584, 2002.@footnote 2@A.J. García et al., J. Biol. Chem. 273, 10988-10993, 1998.@footnote 3@A.J. García et al., Mol. Biol. Cell 10, 785-798, 1999.