Hydration as a governing state variable in the mechanical and electrical response of decellularized extracellular matrix materials.

Decellularized extracellular matrix (dECM) materials derived from biological tissues continue to attract interest as sustainable biomaterials; however, their measured mechanical and electrical responses are highly sensitive to processing history and hydration state. While decellularization and subsequent lyophilization are widely employed to enable storage and handling, the role of hydration in governing experimentally measured dECM behavior remains insufficiently resolved. Here, hydration is examined as a governing state variable influencing the mechanical and electrical responses of dECM materials derived from ovine aortic tissue obtained from abattoir-sourced byproducts. Native, decellularized-lyophilized, and rehydrated samples were evaluated using uniaxial tensile testing, stress-relaxation analysis in circumferential and longitudinal orientations, and direct-current open-circuit potential (DC-OCP) measurements under defined testing conditions. Rehydration induced pronounced changes in early-strain stiffness, viscoelastic relaxation behavior, and electrical signal magnitude, indicating that water content and ionic environment dominate measured dECM responses. Comparable hydration-dependent trends were also observed in structurally distinct dECM tissues, supporting hydration state as a general materials variable rather than a tissue-specific effect. Importantly, the observed responses are interpreted as system-level interactions between dECM and its hydration environment, rather than recovery of native tissue properties. Collectively, these findings emphasize the need to explicitly control and report hydration conditions in dECM characterization and support a materials-centric framework for evaluating mechanical and electrical behavior in decellularized biomaterials.