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Nowadays, antibiotic abuse increases the emergence of multidrug-resistant bacterial strains, which is the major reason for the failure of conventional antibiotic therapies. Therefore, developing novel antibacterial materials or therapies is an urgent demand. In the present study, photothermal and NOreleasing properties are integrated into a single nanocomposite to realize more efficient bactericidal effects. To this end, polydopamine (PDA) coated iron oxide nanocomposite (Fe 3 O 4 @PDA) is used as a photoconversion agent and the core, first three generation dendritic poly(amidoamine) (PAMAM-G3) is grafted on the surface of Fe 3 O 4 @PDA, and subsequently NO is loaded with the formation of NONOate. The resultant Fe 3 O 4 @PDA@PAMAM@NONOate displays controllable NO release property under intermittent 808 nm laser irradiation and excellent bacteria-separation efficiency. Moreover, excellent synergistic photothermal and NO antibacterial effects are observed against both Gramnegative Escherichia coli and Gram-positive Staphylococcus aureus, where bacterial viability and biofilm are significantly reduced. An antibacterial mechanism study reveals that the materials first adsorb onto the bacterial membrane, then cause damage to the membrane by the increased local temperature and the released NO under laser irradiation conditions, finally leak the intracellular components like DNA and induce bacteria death. The work provides a novel way for designing of antibacterial materials with higher efficiency.

For decades, hydrogen (H2) gas has been recognized as an excellent antioxidant molecule that holds promise in treating many diseases like Alzheimer's, stroke, cancer, and so on. For the first time, active hydrogen is demonstrated to be highly efficient in antibacterial, antibiofilm, and wound‐healing applications, in particular when used in combination with the photothermal effect. As a proof of concept, a biocompatible hydrogen‐releasing PdH nanohydride, displaying on‐demand controlled active hydrogen release property under near‐infrared laser irradiation, is fabricated by incorporating H2 into Pd nanocubes. The obtained PdH nanohydride combines both merits of bioactive hydrogen and photothermal effect of Pd, exhibiting excellent in vitro and in vivo antibacterial activities due to its synergistic hydrogen‐photothermal therapeutic effect. Interestingly, combinational hydrogen‐photothermal treatment is also proved to be an excellent therapeutic methodology in healing rats' wound with serious bacterial infection. Moreover, an in‐depth antibacterial mechanism study reveals that two potential pathways are involved in the synergistic hydrogen‐photothermal antibacterial effect. One is to upregulate bacterial metabolism relevant genes like dmpI, narJ, and nark, which subsequently encode more expression of oxidative metabolic enzymes to generate substantial reactive oxygen species to induce DNA damage and another is to cause severe bacterial membrane damage to release intracellular compounds like DNA.

On the basis of the synthesis of water-soluble poly(epsilon-caprolactone)-poly(ethylene glycol)-poly(epsilon-caprolactone) (PCL-PEG-PCL) block copolymers, the supramolecular hydrogels were fabricated rapidly in aqueous solutions by their inclusion complexation with alpha-cyclodextrin. X-ray diffraction (XRD) analyses confirmed the supramolecular self-assemblies of alpha-cyclodextrin threaded onto amphiphilic PCL-PEG-PCL block copolymers. The resulting hydrogels display a high degree of elasticity, with the storage modulus (G') greater than the loss modulus (G'') over the entire range of frequency. Moreover, their viscosity greatly diminished as they were sheared. By controlling the molecular weight of the PEG component in the block copolymers and the content of the block copolymer, their rheological properties could be modulated. Such hydrogel materials have the potential to be used as tissue engineered scaffolds, biosensors in the human body, and carriers for controlled drug delivery.

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