Figure 4.

Effect of underlying rigid supports on the mechanical behaviour of thin collagen matrices. Collagen samples were prepared on activated coverglass so that the gel firmly adhered to the surface. Thin attached collagen gels of 1 mg ml⁻¹ (a) and 3 mg ml⁻¹ (b) collagen concentrations were imposed to cyclic loading and unloading mechanical tests at indentation rates of 15 µm s⁻¹, 1 µm s⁻¹ and 1 µm min⁻¹. The irreversible deformation (c) and maximum supported load (d) were obtained from value of unloading function at 0 µN force and value of loading function at 30 µm indentation depth, respectively. Data are presented as mean ± s.d., minimum five measurements per each indentation rate per sample.