Multifunctional hydrogels acting as wound dressing have received extensive attention in soft tissue repair; however, it is still a challenge to develop a non-antibiotic-dependent antibacterial hydrogel that has tunable adhesion and deformation to achieve on-demand removal. Herein, an asymmetric adhesive hydrogel with near-infrared (NIR)-triggered tunable adhesion, self-deformation, and bacterial eradication is designed. The hydrogel is prepared by the crosslinking polymerization of N-isopropylacrylamide and acrylic acid, during the sedimentation of conductive PPy-PDA nanoparticles based on the polymerization of pyrrole (Py) and dopamine (DA). Due to the conversion capacity from NIR light into heat for PPy-PDA NPs, the formed temperature-sensitive hydrogel exhibits tissue adhesive as well as NIR-triggered tunable adhesion and self-deformation property, which can achieve an on-demand dressing refreshing. Systematically in vitro/in vivo antibacterial experiments indicate that the hydrogel shows excellent disinfection capability to both Gram-negative and Gram-positive bacteria. The in vivo experiments in a full-layer cutaneous wound model demonstrate that the hydrogel has a good treatment effect to promote wound healing. Overall, the asymmetric hydrogel with tunable adhesion, self-deformation, conductive, and photothermal antibacterial activity may be a promising candidate to fulfill the functions of adhesion on skin tissue, easy removing on-demand, and accelerating the wound healing process.

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Oxidative stress occurs when excess oxidative free radicals are produced in cells, which can overwhelm the normal antioxidant capacity and play an important role in many disease states. Thus, advanced functional materials which can mimic the intracellular antioxidant defense system have a huge potential to become candidates for curing oxidative stress triggered diseases. Herein, a high-performance nanoplatform is developed with a green and mild strategy by combining mimic-enzymatic antioxidant (Fe 3 O 4) and nonenzymatic antioxidant (tannic acid (TA)) for constructing antioxidant defense system (Fe 3 O 4 @ TAn nanoflowers (NFs)). Owing to the excellent peroxidase (POD)-mimic and catalase (CAT)-mimic capacities of Fe 3 O 4 in various conditions, the antioxidant ability of TA and the flower-like morphology, the Fe 3 O 4 @ TAn NFs can effectively scavenge multiple reactive oxygen and nitrogen species. In vitro experiments verify that the Fe 3 O 4 @ TAn NFs demonstrate synergetic antioxidative properties, which can be used to protect blood and cellular components against oxidative damage. Meanwhile, in vivo experiments demonstrate that the Fe 3 O 4 @ TAn NFs exhibit excellent therapeutic effects for systemic inflammation on endotoxemia mice and promote wound healing owing to the excellent antioxidant and anti-inflammatory properties. Thus, this antioxidant defense system expands the toolbox of antioxidative materials and shows potential applications in oxidative stress treatment.

Recently, combining inorganic and organic components to develop a dual-functional surface (antibacterial and antifouling) has resulted in widespread investigations. However, the preparation of the dual-functional surface is limited by the availability of reactive surface chemistries at a material's surface. Herein, owing to the multifunctionality of Tannic acid (TA), we proposed a universal, simple, and environmentally friendly approach to integrate the inorganic (Ag nanoparticles) and organic (zwitterionic) components into the membrane surface to simultaneously endow the surface with antifouling and antibacterial ability, respectively. The Ag nanoparticles (NPs) and zwitterionic polymer were codeposited onto the TA decorated surface. The obtained membrane surface exhibited long-term and robust bactericidal activity. Meanwhile, due to the zwitterionic structure, the membrane could effectively resist bacterial adhesion. Additionally, the proposed strategy could also be employed to construct many kinds of dual-functional surfaces because of the versatile functionality of tannic acid.

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Nanofibrous membranes with surface migration of hydrophilic and negatively charged groups were designed for ultrafast water purification and smart dye separation.

Pathogenic bacterial infection has become a serious medical threat to global public health. Once the skin has serious defects, bacterial invasion and the following chain reactions will be a thorny clinical conundrum, which takes a long time to heal. Although various strategies have been used to eradicate bacteria, the treatment which can simultaneously disinfect and regulate the infection-related host responses is rarely reported. Herein, inspired by the host microenvironment, a photoenhanced dual-functional nanomedicine is constructed (Hemin@Phmg-TA-MSN) for localized bacterial ablation and host microenvironment modulation. The “NIR-triggered local microthermal therapy” and positively charged surface endow the nanomedicine with excellent bacterial capture and killing activities. Meanwhile, the nanomedicine exhibits broad-spectrum reactive oxygen species (ROS) scavenging activity via the synergistic effect of hemin and tannic acid with photoenhanced electron and hydrogen transfers. Furthermore, the in vivo experiments demonstrate that the dual-functional nanomedicine not only presents robust bacterial eradication capability, but also triggers the oxidative stress and inflammatory microenvironment regulation. The work not only shows a facile and effective way for infected wound management but also provides a new horizon for designing novel and efficient anti-infection therapy shifting focus from bacteria treatment to host microenvironment modulation.