Microenvironment-adaptive cationic guar gum hydrogel co-loaded with BPNS@MnO₂ nanozyme and berberine for infected...

Infected burn wounds are characterized by bacterial invasion, oxidative stress, and persistent inflammation, which severely impair tissue regeneration. Herein, we report a crosslinker-free, hydrogen-bonded cationic guar gum hydrogel (CBBM) co-loaded with berberine (BBR) and MnO₂-coated black phosphorus nanosheets (BPNS@MnO₂) for the microenvironment-adaptive treatment of infected burn wounds. The dynamic guar gum network endowed the hydrogel with injectability, self-healing ability, and conformal adaptability. BPNS@MnO₂ exhibited pH-dependent enzyme-like activities, including OXD-like antibacterial activity under acidic conditions and SOD-/CAT-like ROS-scavenging activity under near-neutral conditions and endowed the hydrogel with NIR-triggered photothermal responsiveness. Moreover, NIR irradiation further enhanced the antibacterial efficacy and moderately enhanced BBR release from the hydrogel. In vitro, CBBM combined with NIR irradiation achieved potent antibacterial efficacy against S. aureus and E. coli under the tested conditions and reduced intracellular ROS levels. In vivo, the CBBM + NIR treatment accelerated infected burn wound healing, achieving a wound closure rate of 97.53 ± 2.01% by day 14, accompanied by reduced inflammation, enhanced collagen deposition, and increased expression of the angiogenesis-related markers VEGF and CD31. These results demonstrate that the CBBM hydrogel is a promising multifunctional guar gum-based dressing for infected burn wound healing by integrating local drug delivery, catalytic regulation, and photothermal activation.