Effect of Storage Conditions on Rheological Properties of Decellularized Extracellular Matrix-Based Injectable Hydrogels.

Decellularized extracellular matrix-based scaffolds have gained significant attention for tissue regeneration applications. However, there is a limited understanding of how storage conditions influence the rheological and biological properties of decellularized matrix-based injectable formulations. This study investigates the effects of different storage conditions (4°C, -80°C, and freeze-dried) on the rheological properties of a decellularized porcine peripheral nerve-derived extracellular matrix hydrogel. Our results demonstrated that, compared to storage at 4°C, formulations stored at -80°C and freeze-dried maintained comparable gelation kinetics (complete gelation within 11 min), mechanical properties (storage modulus around 300-350 Pa), and shear-thinning behavior across multiple time-points (Days 0, 3, 7, and 14 for -80°C), similar to freshly prepared formulations at Day 0. Solution stored at 4°C demonstrated a decrease in mechanical stiffness of hydrogel with time, however their gelation kinetics remained similar to Day 0. The solutions stored at -80°C and resuspended freeze-dried solutions maintained their complex viscosity, while 4°C stored solutions had relatively low complex viscosity as compared to freshly digested solutions. Overall, our findings suggest that -80°C storage and freeze-drying are suitable approaches for preserving decellularized porcine peripheral nerve-derived extracellular matrix formulations. Given the translational potential of these injectable biomaterials, understanding the influence of storage conditions on rheological performance is critical for developing appropriate storage and shipping strategies.