Sterilization is essential for hydrogel-based biomaterials, but it can also determine the final material state. This study used ionically crosslinked alginate hydrogels as a model system to evaluate sterilization as a coupled process linking microbial inactivation and hydrogel structural reorganization. Steam sterilization, gamma irradiation, ethylene oxide (EtO), ultraviolet (UV) irradiation, and high hydrostatic pressure (HHP) treatment were assessed within the same model system. Microbiological effectiveness was assessed using surface- and matrix-associated contamination models, while structural responses were evaluated by rheology, dimensional changes, and swelling behavior. Steam sterilization, gamma irradiation, EtO, and selected HHP conditions resulted in no detectable microbial growth under the tested conditions, whereas UV irradiation was insufficient to eliminate detectable growth from matrix-associated contamination. However, microbiologically effective treatments produced distinct material profiles. Steam generated a compact and stiff hydrogel state, gamma irradiation produced softened but deformation-tolerant networks, EtO caused pronounced dimensional alteration and high deformability, and HHP produced softened, water-accessible hydrogels with parameter-dependent responses. These findings show that sterilization method selection should integrate microbial inactivation with the final structural state required for application-specific hydrogel performance.

Sterilization-related treatments are commonly applied to hydrogel-based biomaterials, and rheological data provide a basis for describing their post-treatment material profiles. This data article presents raw oscillatory rheometry data from untreated calcium-alginate hydrogel samples and from samples exposed to ultraviolet irradiation, ethylene oxide treatment, steam sterilization, gamma irradiation, and high hydrostatic pressure treatment. The dataset was generated by amplitude sweep measurements using an Anton Paar MCR 102e rheometer with parallel-plate geometry at 37 °C. The deposited CSV files include point-by-point values for shear strain, shear stress, storage modulus, loss modulus, loss factor, torque, and complex viscosity. Corresponding plots show storage and loss moduli versus shear strain, storage and loss moduli versus shear stress, and complex viscosity versus shear strain. The files are organized by treatment group; gamma-treated samples are arranged by dose, and high hydrostatic pressure-treated samples by pressure level and number of cycles. The dataset can be reused to extract viscoelastic parameters, define the linear viscoelastic region using user-selected criteria, generate rheological profiles for untreated and treatment-exposed hydrogels, and support exploratory analysis and testing of rheological data-processing workflows.