Remedying a multidrug-resistant (MDR) bacteria wound infection is a major challenge due to the inability of conventional antibiotics to treat such infections against MDR bacteria. Thus, developing wound dressings for wound care, particularly against MDR bacteria, is in huge demand. Here, we present a strategy in designing wound dressings: we use a small molecule (6-aminopenicillanic acid, APA)-coated gold nanoparticles (AuNPs) to inhibit MDR bacteria. We dope the AuNPs into electrospun fibers of poly(ε-caprolactone) (PCL)/gelatin to yield materials that guard against wound infection by MDR bacteria. We systematically evaluate the bactericidal activity of the AuNPs and wound-healing capability via the electrospun scaffold. APA-modified AuNPs (Au_APA) exhibit remarkable antibacterial activity even when confronted with MDR bacteria. Meanwhile, Au_APA has outstanding biocompatibility. Moreover, an in vivo bacteria-infected wound-healing experiment indicates that it has a striking ability to remedy a MDR bacteria wound infection. This wound scaffold can assist the wound care for bacterial infections.

Solar carbon dioxide (CO 2 ) conversion is an emerging solution to meet the challenges of sustainable energy systems and environmental/climate concerns. However, the construction of isolated active sites not only influences catalytic activity but also limits the understanding of the structure−catalyst relationship of CO 2 reduction. Herein, we develop a universal synthetic protocol to fabricate different single-atom metal sites (e.g., Fe, Co, Ni, Zn, Cu, Mn, and Ru) anchored on the triazine-based covalent organic framework (SAS/Tr-COF) backbone with the bridging structure of metal−nitrogen−chlorine for highperformance catalytic CO 2 reduction. Remarkably, the as-synthesized Fe SAS/Tr-COF as a representative catalyst achieved an impressive CO generation rate as high as 980.3 μmol g −1 h −1 and a selectivity of 96.4%, over approximately 26 times higher than that of the pristine Tr-COF under visible light irradiation. From X-ray absorption fine structure analysis and density functional theory calculations, the superior photocatalytic performance is attributed to the synergic effect of atomically dispersed metal sites and Tr-COF host, decreasing the reaction energy barriers for the formation of *COOH intermediates and promoting CO 2 adsorption and activation as well as CO desorption. This work not only affords rational design of state-of-the-art catalysts at the molecular level but also provides in-depth insights for efficient CO 2 conversion.

Multimodal imaging-guided diagnosis and therapy has been highlighted in the area of theranostic nanomaterials. To provide more suitable theranostic candidates, Prussian blue (PB)/manganese dioxide (MnO) hybrid nanoparticles (PBMn) smaller than 50 nm are prepared by a one-pot method. MnO, which is reduced from KMnO, not only controls the particle size, the optical properties, and the transverse relaxation rate (r) of PB but also enhances the catalysis efficacy of PB to HO for oxygen generation. PBMn can serve as a photoacoustic imaging (PAI) and longitudinal relaxation (T) mode magnetic resonance imaging contrast agent (14 times and 1.8 times of the saline-treated group, respectively). Injection of PBMn can regulate the oxygen partial pressure of the tumor tissue from 2.1 ± 0.2 to 9.3 ± 0.4 kPa and rearrange the ratio of oxygenated hemoglobin and deoxygenate hemoglobin inside the tumor, which favor the enhancement of the diamagnetic T-weighted imaging (TWI) signal intensity (two times that of the saline-treated group). Furthermore, PBMn-mediated PTT can efficiently inhibit the growth of the MCF-7 tumor in vitro and in vivo. PBMn can serve as a PAI/T/T trimodal contrast agent and in imaging-guided PTT, as well as in the oxygen regulation of the exografted breast cancer.

The emergence of multi-drug-resistant pathogens threatens the healthcare systems world-wide. Recent advances in phototherapy (PT) approaches mediated by photo-antimicrobials (PAMs) provide new opportunities for the current serious antibiotic resistance. During the PT treatment, reactive oxygen species or heat produced by PAMs would react with the cell membrane, consequently leaking cytoplasm components and effectively eradicating different pathogens like bacteria, fungi, viruses, and even parasites. This Perspective will concentrate on the development of different organic photo-antimicrobials (OPAMs) and their application as practical therapeutic agents into therapy for local infections, wound dressings, and removal of biofilms from medical devices. We also discuss how to design highly efficient OPAMs by modifying the chemical structure or conjugating with a targeting component. Moreover, this Perspective provides a discussion of the general challenges and direction for OPAMs and what further needs to be done. It is hoped that through this overview, OPAMs can prosper and will be more widely used for microbial infections in the future, especially at a time when the global COVID-19 epidemic is getting more serious.