Biomechanical Evaluation of a Poly(vinyl alcohol) Hydrogel Testicular Prosthesis for Tissue-Mimicking Soft-Tissue...

Current testicular prostheses are predominantly manufactured from silicone elastomers and often fail to reproduce the biomechanical and viscoelastic characteristics of native testicular tissue. This study aimed to develop and mechanically characterize a poly(vinyl alcohol) (PVA) hydrogel-based testicular prosthesis with tissue-mimicking properties. PVA hydrogels with concentrations of 5%, 10%, and 15% (w/v) were fabricated using a freeze-thaw crosslinking process and evaluated through comprehensive mechanical testing, including uniaxial compression, tensile testing, stress relaxation, creep, dynamic mechanical analysis (DMA), and cyclic compression fatigue testing. A prototype hydrogel testicular prosthesis was subsequently fabricated and its mechanical performance compared with native testicular tissue and a commercially available silicone implant. Mechanical behavior was strongly dependent on polymer concentration. Increasing PVA concentration resulted in significant increases in compressive modulus, tensile strength, toughness, storage modulus, and fatigue resistance. The 10% PVA hydrogel demonstrated the closest overall agreement with native tissue, exhibiting a compressive modulus of 78 ± 10 kPa compared with 64 ± 12 kPa for native tissue, while maintaining comparable tensile strength, recovery ratio, and energy dissipation characteristics. Viscoelastic characterization revealed tissue-like stress relaxation and creep responses, whereas cyclic compression testing demonstrated stable mechanical performance over 1000 loading cycles. In contrast, the silicone implant exhibited lower compliance, reduced energy dissipation capacity, and inferior overall biomechanical similarity to native tissue. These findings demonstrate that freeze-thaw PVA hydrogels provide a promising platform for biomimetic testicular prostheses. By tailoring polymer concentration, hydrogel implants can achieve mechanical and viscoelastic properties that more closely replicate native tissue than conventional silicone devices. The proposed hydrogel-based approach may improve implant realism and patient outcomes, providing a foundation for future long-term durability studies and in vivo evaluation.