Figure 6.

The effect of Ca²⁺ and Ca²⁺ chelator (EDTA) on rheological properties of ND-mucin solutions. (A) Steady shear viscosity, η, and oscillatory viscosity, |η*|, of 30 mg/mL ND-mucin treated with 0.1 M Ca²⁺, 0.1 M Ca²⁺/0.1 M EDTA and 0.1 M EDTA versus shear rate, $\dot{\gamma }$, and angular frequency, ω, measured using parallel-plate geometry at a gap of 40 μm. Insert shows the plot of shear stress, σ, versus shear rate, $\dot{\gamma }$, of the same data. (B) Comparison of the storage modulus, G′ (ω), and loss modulus, G″ (ω), of 30 mg/mL ND-mucin treated with 0.1 M Ca²⁺, 0.1 M Ca²⁺/0.1 M EDTA and 0.1 M EDTA. (C) The ensemble averaged MSD curves of 0.5 μm colloidal particles in 30 mg/mL ND-mucin treated with 0.1 M Ca²⁺, 0.1 M Ca²⁺/0.1 M EDTA and 0.1 M EDTA with the log-log scaling to be τ^0.46, τ^0.12, τ^0.5 and τ^0.83, respectively. (D) The ensemble averaged MSD curves of 0.5 μm colloidal particles in 10 mg/mL ND-mucin treated with 0.1 M Ca²⁺, 0.1 M Ca²⁺/0.1 M EDTA and 0.1 M EDTA with the log-log scaling to be τ^0.85, τ^0.41, τ^0.89 and τ¹, respectively.