Bacterial infections caused by pathogens have always been a thorny issue that threatens human health, and there is urgent need to develop a new generation of antimicrobial nano-agents and treatments. Herein, biodegradable nickel disulfide (ND) nanozymes as excellent antibacterial agents that integrate excellent photothermal performance, nano-catalysis property, and glutathione (GSH)depleting function have been successfully constructed. The ND nanozymes can effectively catalyze the decomposition of H 2 O 2 to produce ,OH, and the hyperthermia of ND nanozymes generated by photothermal therapy (PTT) can further increase its catalytic activity, which provides rapid and effective bacterial killing effect compared with nano-catalytic treatment or PTT alone. Surprisingly, the ND nanozymes have the ability of GSH consumption, thus enhancing its sterilization effect. Moreover, the ND nanozymes are biodegradable nanomaterials that do not cause any significant toxicity in vivo. Collectively, the ND nanozymes with excellent photothermal performance, catalytic activity, and GSH-depleting function are used for high-efficiency sterilization.

The ever-growing global crisis of multidrug-resistant bacteria has triggered a tumult of activity in the design and development of antibacterial formulations. Here, atomically thin antimony selenide nanosheets (Sb2Se3 NSs), a minimal-toxic and low-cost semiconductor material, were explored as a high-performance two-dimensional (2D) antibacterial nanoagent via a liquid exfoliation strategy integrating cryo-pretreatment and polyvinyl pyrrolidone (PVP)-assisted exfoliation. When cultured with bacteria, the obtained PVP-capped Sb2Se3 NSs exhibited intrinsic long-term antibacterial capability, probably due to the reactive oxygen species generation and sharp edge-induced membrane cutting during physical contact between bacteria and nanosheets. Upon near-infrared laser irradiation, Sb2Se3 NSs achieved short-time hyperthermia sterilization because of strong optical absorption and high photothermal conversion efficiency. By virtue of the synergistic effects of these two broad-spectrum antibacterial mechanisms, Sb2Se3 NSs exhibited high-efficiency inhibition of conventional Gram-negative Escherichia coli, Gram-positive methicillin-resistant Staphylococcus aureus, and wild bacteria from a natural water pool. Particularly, these three categories of bacteria were completely eradicated after being treated with Sb2Se3 NSs (300 μM) plus laser irradiation for only 5 min. In vivo wound healing experiment further demonstrated the high-performance antibacterial effect. In addition, Sb2Se3 NSs depicted excellent biocompatibility due to the biocompatible element constitute and bioinert PVP modification. This work enlightened that atomically thin Sb2Se3 NSs hold great promise as a broad-spectrum 2D antibacterial nanoagent for various pathogenic bacterial infections.

A cryo-assisted liquid exfoliation approach was developed to prepare atomically thin Sb2Se3 colloidal nanosheets for simultaneous photoacoustic imaging and photothermal therapy.

The accompanying relationship between tumor and inflammation raises the concept of concurrent antitumor and anti-inflammation treatment in the clinic. Despite the wide application of 2D atomic crystals for cancer theranostics, their anti-inflammation function has been rarely explored. Herein, it is reported that niobium diselenide nanosheets (NbSe 2 NSs), a "star" 2D superconducting atomic crystal, can serve as a theory-oriented 2D nanoagent from anti-inflammation to antitumor. A safe-by-design exfoliation strategy, integration of cryo-pretreatment and DNA-assisted exfoliation, is proposed for high-efficiency exfoliation of atomically thin NbSe 2 NSs. Especially, computational simulation reveals that NbSe 2 NSs effectively eliminate reactive oxygen and nitrogen species (RONS) via hydrogen atom transfer and redox reaction. Upon the injection of NbSe 2 NSs into BALB/c mice, not only U87 subcutaneous tumors are rapidly ablated after photoacoustic imaging-guided precise localization of tumor contour, but also lipopolysaccharide-induced rear thigh inflammation or photothermal therapymediated inflammation is efficiently inhibited through RONS scavenging. In addition, NbSe 2 NSs are highly biocompatible both in vitro and in vivo due to high-security element constituent and DNA modification. The work extends the biomedical application of 2D atomic crystals for anti-inflammatory treatment.

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