Tissue engineering: Hydrogel scaffolds and mechanical properties as key design parameters

The global demand for effective tissue regeneration strategies continues to rise due to the increasing burden of trauma, chronic diseases, and age-related tissue degeneration. Hydrogels are widely explored as promising biomaterials for tissue engineering due to their high water content, swelling capacity, ability to absorb liquid exudates, flexible structure, and structural resemblance to the extracellular matrix. Under appropriate design and formulation, many hydrogels also demonstrate favorable levels of biocompatibility; however, this property can vary depending on the composition, crosslinking chemistry, and degradation products of the hydrogel. Among the key design parameters, the mechanical properties of hydrogels are critical determinants of their success in tissue engineering, as they directly govern cell-matrix interactions through mechanotransduction. The stiffness and viscoelasticity of the scaffold influence cell adhesion, migration, proliferation, and lineage commitment, while adequate compressive strength and shear resistance are required to preserve structural integrity under physiological loads. Precise tuning of these parameters is essential to reproduce the biomechanical milieu of native tissues and to achieve functional regeneration. Hydrogels are diverse in origin and chemistry, ranging from natural polymers to synthetic and charged networks, each offering unique advantages and limitations. Their versatility has enabled the development of application-specific scaffolds for skin, bone, cartilage, neural, and cardiac tissue regeneration. However, challenges remain in achieving mechanical robustness, long-term stability, and functional integration in vivo. Advances in material science and crosslinking technologies continue to drive the evolution of hydrogel systems with improved mechanical performance and biological response. This review presents a comprehensive scientific perspective on the significance of mechanical properties in hydrogel-based scaffolds and their relevance to tissue-specific applications, offering insights into future directions in regenerative medicine.