Tailoring of a specific pH-induced self-enhanced photothermal cellulose hydrogel for antibiotic-resistant bacteria-infected wound treatment

Implementing differentiated photothermal temperatures in the infected area of the wound and adjacent normal tissue areas can achieve photothermal antibacterial effects while protecting adjacent healthy tissues from potential overheating damage associated with photothermal therapy. Here, a specific pH-induced photothermal temperature self-enhancing cellulose hydrogel was tailored using photothermal-responsive cellulose nanocrystals modified with polyaniline and pH-responsive cellulose nanocrystals loaded with taurine as the staggered network skeletons. The hydrogel possesses exceptional in-situ adaptability and tissue adhesion characteristics, enabling it to adhere to the irregular wound bed. Interestingly, polyaniline on cellulose nanocrystals can be converted from the form of adamantane base to the form of adamantane salt under acidic conditions, exhibiting enhanced photothermal effects. Consequently, the specific acidic microenvironment (pH 5.5–6.8) of infected wounds can elevate the photothermal temperature of hydrogel to 45–48 °C, significantly higher than that (42 °C) of adjacent healthy tissue with pH values of 6.8–7.4. Similarly, taurine grafted onto cellulose nanocrystals via dynamic imine bonding gets gradually released from the hydrogel into infected wounds under specific acidic conditions, thus providing an anti-inflammatory effect. This differential temperature regulation on the infected wound achieves effective photothermal antibacterial treatment while preventing overheating damage to normal tissue.