Dynamic borax-crosslinked transparent and antifreezing tragacanth gum-glycerol hydrogel for biomedical use

Multifunctional hydrogels that combine stretchability, adhesion, self-healing, and transparency maintain significant promise for biomedical applications such as electronic skin, wound dressings, and wearable devices. This study presents a novel hydrogel fabricated through a three-dimensional dynamic cross-linked network of tragacanth gum (TG), glycerol (G), and borax (B). Inspired by the strong hydrogen bonding between glycerol and TG along with the chelation-mediated cross-linking facilitated by borax, we engineered a three-dimensional (3D) dynamic network hydrogel from these materials. The TG-G-B hydrogel exhibited remarkable mechanical properties, including ultrahigh stretchability (elongation up to 480 %) and a swelling ratio of approximately 300 %, with proper adhesion. Notably, the hydrogel demonstrated a rapid self-healing ability, autonomously restoring its integrity by reforming into a continuous structure after damage. Transparency increased with borax concentration, achieving 132 % at optimal ratios. The hydrogel also exhibited high water vapor transmission rate (2324 g/m².day), ensuring efficient oxygen and moisture permeability, both critical for wound healing. Biocompatibility was confirmed via MTT assays, revealing no cytotoxicity toward L929 fibroblast cells. Due to its multifunctionality and biocompatibility, the TG-G-B hydrogel film emerges as a promising material for diverse biomedical engineering applications, particularly in wound dressings, electronic skin, and wearable health monitoring devices.