Evaluating visco-hyperelastic mechanical responses of hydrogel-based scaffolds and their potential for biomechanical restoration of the human mandibular joint.

This study researches the viscous and hyperelastic mechanical behaviors of hydrogel-based nanocomposite materials, including: (i) a composite of human methacryloyl platelet lysate (hPLMA), human platelet lysates (hPL), and nanohydroxyapatite (nHA); (ii) bovine serum albumin methacryloyl (BSAMA); and (iii) hyaluronic acid methacryloyl (HAMA). These materials stand out for their enhanced bioactivity and mechanical strength compared to traditional hydrogels. Their potential applications in various scaffold architectures and the biomechanical restoration of the mandibular joint are investigated. Mechanical compression and relaxation tests are performed on the hydrogel-based samples, with varying nHA content (0%, 1%, and 5%) in the hPL/hPLMA composite, to characterize their visco-hyperelastic behavior. Mechanical parameters are optimized using a micro-genetic algorithm. Results show that increasing nHA content raises compressive stress and intensifies the viscoelastic response. Besides, higher strut density and staggered orthogonal patterns produce more uniform stress distribution despite a less stable viscous response. In in silico simulations of the human mandible, a multimaterial scaffold was created, featuring a hydrogel core with ceramic-based scaffold ends (hydroxyapatite-based cement enriched with hPL). The ceramic phase provided effective mechanical protection for the hydrogel. Besides, substituting the hPL/hPLMA core with HAMA reduced the stress values in the hydrogel phase, while using BSAMA led to increased stress. This study introduces a novel framework integrating experimental data, mechanical optimization, and numerical simulations to elucidate the viscoelastic behavior of hydrogel-based nanocomposite inks and multimaterial scaffolds. This research advances the development of next-generation biomaterials with improved durability and functionality, promoting regenerative medicine and personalized tissue engineering.