FIG. 3.

(A) The PDN hydrogel+collagen composites have shear-thinning behavior at 20°C as demonstrated by a substantial decrease in viscosity over a shear sweep from 0.100/s to 6000/s. (B) The PDN hydrogel+collagen composite is injectable. At high shear rate (6000/s) and low temperature (20°C), the viscosity of the composite is very low, comparable to a liquid. At low shear rate (0.100/s) and low temperature, the viscosity recovers. At low shear rate and physiological temperature (37°C), the viscosity undergoes an ∼100-fold increase, indicative of gelation. Color images available online at www.liebertpub.com/tea