Rheological Characterization
Mechanical properties of the hydrogel were characterized via an AR-2000 computer controlled rheometer (TA Instruments, Leatherhead, Surrey, UK) fitted with a parallel plate geometry (diameter: 40 mm) and a temperature control system. All measurements were taken at a constant temperature of 37 ̊C. Briefly, medium grit sandpaper was used as a base on top of the bottom plate. The sandpaper was allowed to equalize temperature with the bottom plate (37 ̊C) for 5 minutes. Hydrogel samples were removed from their cylindrical dies (4 mm diameter by 2 mm height) and placed atop the sandpaper. A sciatic nerve from a humanely euthanized turkey was used as a control. For all samples, the top plate was lowered to 50% the height of the hydrogel, and 2 minutes were allowed for temperature equalization. A stress sweep (σ 0.7 – 1000 Pa) was performed for each concentration of genipin. Storage moduli (G’) and applied sheer stresses (σ) were recorded and linear viscoelastic regions (LVR) were calculated for each sample