Tannic Acid-Inspired antibacterial hydrogel with antioxidant and anti-inflammatory properties for Staphylococcus aureus-infected wound healing

To reduce the harmful effects of Staphylococcus aureus (S. aureus) infection during wound healing, the exploitation of novel hydrogel-based wound dressings with antibacterial and anti-inflammatory abilities is necessary. Herein, we proposed a novel alginate-based antibacterial hydrogel (SPT) consisting of boronate ester bonds formed between tannic acid (TA) and phenylboronic acid (PBA). TA not only functions as a crosslinker of the hydrogel, but also as an antibacterial agent with antioxidant and anti-inflammatory capacities, which achieved continuous release in response to the mildly-acidic bacterial infection microenvironment. 1H-nuclear magnetic resonance (1H NMR), Fourier transformed infrared spectroscopy (FTIR), ultraviolet-visible (UV-vis) spectroscopy, rheometer and scanning electron microscope (SEM) verified the successful production of hydrogel and pHdependent release of TA. Furthermore, its bactericidal and antioxidant activities were intensively assessed in vitro and in vivo. The experimental results illustrated that the SPT hydrogel possessed good antimicrobial ability against S. aureus and anti-inflammatory capacity due to the pH-responsive release of TA. In addition, the SPT hydrogel exhibited satisfying antioxidant capacities in the free radical assays and ROS fluorescence staining. To sum up, the prepared SPT hydrogel showed good antibacterial effect against S. aureus and anti-inflammatory capacity. Therefore, it has great potential to be employed as wound dressing in clinical applications.