Microsphere-Loaded and Borax-Reinforced Polyacrylic Acid (PAA)/Polyvinyl Alcohol (PVA) Hydrogels Incorporating Tannic Acid: Ultra-High Toughness and Antibacterial Properties for Artificial Intelligence Skin

Hydrogel-based dressings are widely used in wound healing. Herein, we report a polyacrylic acid (PAA)/polyvinyl alcohol (PVA) composite hydrogel fabricated via self-catalyzed free radical polymerization, with borax serving as the reinforcing phase. Meanwhile, metal-ligand coordination bonding between tannic acid (TA) and Fe³⁺ further elevates the crosslinking density of the hydrogel network. Magnetic chitosan microspheres (MCMs) were synthesized by emulsion cross-linking and loaded with two antibacterial agents, namely tetracycline hydrochloride (TH) and berberine hydrochloride (Bbh). The incorporation of MCMs into the hydrogel matrix resulted in the development of a multifunctional composite hydrogel suitable for wound dressing applications. Results demonstrated that the composite hydrogel containing a specific concentration of 4‰ (w/v) borax and 20 mg/mL MCMs exhibited superior performance, including enhanced mechanical strength, improved responsiveness, sustained drug release, and potent antibacterial efficacy. The core novelty of this work lies in the synergistic integration of borax-based mechanical reinforcement, MCM-mediated dual drug loading and sustained release, and the self-catalyzed polymerization system. This innovative structural and functional collaboration effectively optimizes the mechanical stability of the hydrogel dressing and achieves synergistic antibacterial and intelligent responsive therapeutic performances, providing a reliable and high-efficiency candidate for advanced wound care and next-generation wound dressing applications.