Professor McGill University Montreal, Quebec, Canada
Introduction: Vocal folds play a crucial role in voice production, phonation, and singing. Pathological conditions can impair their function, leading to voice disorders. Tissue engineering offers promising repair and regeneration strategies, aiming to develop scaffolds that mimic the native vocal fold tissue microenvironment. Tissue regeneration is intricately influenced by the dynamic interplay between the physical attributes of tissue engineering scaffolds and the resulting biological responses. Hence, the successful regeneration of vocal fold tissue necessitates a comprehensive understanding of the effects of substrate properties on cellular behavior. This study focuses on understanding how scaffold mechanics and architecture influence the immunological and reparative activities of vocal fold tissues.
Materials and
Methods: We engineered a tunable macroporous hydrogel system using Gelatin Methacryloyl (GelMA) and Polyethylene Glycol Diacrylate (PEGDA), with Polyethylene Glycol (PEG) as a porogen. By varying PEGDA molecular weights, hydrogels with different mechanical and architectural properties were created. Mechanical characteristics were assessed via tensile strength tests and rheometry, while morphology was analyzed using Scanning Electron Microscopy (SEM) and confocal microscopy. A series of biological assays was conducted: hVFFs morphology, differentiation, and collagen synthesis were evaluated through immunostaining; fibroblast proliferation was studied using the WST-1 assay; cell migration was assessed via the Boyden chamber assay; and macrophage polarization and secretion profiles were investigated using immunostaining and ELISA.
Results, Conclusions, and Discussions: Results The results revealed that increasing the molecular weight of PEGDA from 700 Da to 10,000 Da resulted in decreased hydrogel stiffness, from 62.6 kPa to 8.8 kPa, and increased pore dimensions from approximately 64.9 µm to 137.4 µm. Biological evaluations demonstrated that hydrogels with higher stiffness promoted fibroblast proliferation and spreading, albeit with an increased propensity for fibrosis, owing to a surge in myofibroblast differentiation and collagen synthesis. In contrast, hydrogels with greater molecular weights had a softer matrix with expanded pores, enhancing cellular migration and promoting an M2 macrophage phenotype conducive to tissue healing. The findings support the P6000 hydrogels as prime candidates for vocal fold repair and show that the macroporous hydrogels can be tuned to serve in various tissue engineering applications. Conclusion Understanding the interplay between the physical properties of hydrogels and the immune and reparative activities of vocal folds is paramount in designing scaffolds that not only support but also actively contribute to vocal fold tissue regeneration. This study has elucidated such relationships using macroporous GelMA/PEGDA hydrogels. This research underscores the importance of fine-tuning hydrogel mechanics and porosity to tailor scaffolds specifically for vocal fold regeneration. By focusing on the unique requirements of vocal fold tissue, such as the need for optimal mechanical support and favorable cellular interactions, GelMA/PEGDA hydrogels can be effectively adapted to meet the specific challenges of regenerating this specialized tissue.
