Hyaluronic Acid-silk Fibroin Hydrogel for Salivary Gland Tissue Engineering

Cell-material-based therapies have emerged as a promising avenue within tissue engineering strategies for salivary gland (SG) regeneration. However, replicating the complex architecture and functional properties of SG tissue remains a challenge. In this study, we used an engineered in situ cross-linked hydrogel designed to recapitulate the biochemical and rheological characteristics of SG, providing a platform for investigating SG cell behavior and organoid differentiation. Among hydrogel formulations, derived from enzymatically cross-linked blends of tyramine-conjugated hyaluronic acid (HA-Tyr) and silk fibroin (SF), a blend of 2.5% HA-Tyr and 4% SF4 (HA-Tyr-SF4) showed rheological properties partially comparable to native submandibular glands (SMG), achieving high cell viability. Comparative analyses of cell-scaffold interactions in 2D and 3D cultures revealed that cell encapsulation within HA-Tyr-SF4 hydrogel enhanced cell-cell spatial organization. Encapsulated NS-SV-AC cells and human SG organoids (hSGOs) exhibited morphogenesis, supported by transcriptomic data indicating upregulation of genes associated with SG development, extracellular matrix remodeling, and epithelial phenotype stabilization. Furthermore, hSGOs grown in HA-Tyr-SF4 or matrix (MA) of basement membrane extract (BME) displayed similar transcriptomic profiles. This study establishes HA-Tyr-SF4 as a reproducible, biologically active scaffold with substantial potential for SG tissue engineering and regenerative medicine applications.