To visualize direct binding of cells to purified LTBP-1, we used microcontact printing (Goffin et al., 2006 (link)). In brief, polydimethylsiloxane stamps exhibiting islet topographies with dimensions of 10-µm length, 1.5-µm width, and 4-µm spacing were coated with 0.2 µg/ml LTBP-1 or FN (FC010; EMD Millipore) for 1 h. Protein prints were created on plastic coverslips, and protein-free areas were passivated with poly-l-lysine–polyethylene glycol for 10 min. Myofibroblasts were seeded on prints in serum-free media for 4 h before being processed for immunostaining. For cell adhesion quantification, tissue culture plastic wells were coated with 20 µg/ml LTBP-1, and hDMfs were seeded for 4 h in the presence of cyclic peptides antagonizing 10 µM RGD (12135-010; Gibco), 10 µM control RGE (12139-010; Gibco), integrins αvβ3/αvβ5 (EMD121974; Cilengitide), αvβ3 integrin (EMD66203), and scrambled control (EMD135981; Merck). Blocking antibodies were used directed against 10 µg/ml integrins β1 (MAB1965; EMD Millipore), β3 (MAB1976; EMD Millipore), and β5 (MAB1961; EMD Millipore). Additional controls were 10 µM RGE and human IgG (I9135; Sigma-Aldrich). Samples were rigorously washed three times before cells were fixed for quantification and staining.