Development and Evaluation of a Biomimetic Artificial TMJ Disc Using Anisotropic Polyvinyl Alcohol and Highly Crosslinked Decellularized Matrix

The temporomandibular joint (TMJ) disc is integral to TMJ function, facilitating load distribution and smooth articulation. However, damage from degenerative or traumatic conditions often results in TMJ dysfunction, for which effective replacements are unavailable due to the disc's unique anisotropic mechanical properties and complex biochemical environment. This study presents a biomimetic artificial TMJ disc integrating anisotropic polyvinyl alcohol (PVA) hydrogel with a highly crosslinked decellularized extracellular matrix (dECM), aiming to address these challenges. The artificial disc leverages the synergistic properties of its components. The PVA hydrogel, fabricated via directional freezing and salt precipitation, exhibits anisotropic elasticity, high water content, and robust lubricating properties. The Genipin-crosslinked dECM retains native structural heterogeneity, enhancing mechanical strength and resisting enzymatic degradation. Mechanical evaluations demonstrate that the artificial disc achieves elastic modulus, fatigue resistance, and friction characteristics that not only mimic but exceed those of the native TMJ disc. Extensive biocompatibility assessments, including hemolysis, cytotoxicity, and live/dead cell assays, reveal the artificial disc's excellent cellular compatibility and low inflammatory potential. In vitro and in vivo degradation studies underscore its structural integrity over extended periods, highlighting its potential for long-term functionality. The in situ application of the artificial disc in a sheep TMJ model further validates its efficacy. Implanted discs successfully integrated into the joint without triggering adverse immune responses, preserving joint morphology and protecting articular cartilage from degenerative changes. Histological and imaging analyses confirmed minimal inflammation and stable structural performance, supporting its utility in physiological conditions. This multidisciplinary study combines innovations in biomaterials and bioengineering, offering a transformative solution for TMJ disc reconstruction. The biomimetic artificial disc represents a significant advancement in treating TMJ disorders and provides a robust framework for future cartilage tissue engineering applications.