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.
Monodisperse chromogenic amylose–iodine nanoparticles were developed as an efficient broad-spectrum antibacterial agent under the assistance of near-infrared laser irradiation.
Although RNAs play a critical role in all cellular processes, the elucidation of their 3D structures is a daunting task. Naked RNAs are difficult to crystallize, and NMR spectroscopy is generally limited to small RNA fragments. As there is little apparent correlation between RNA primary sequences and three--dimensional folding, the usefulness of a pure computational structure prediction approach is also limited. Currently, general methods for high throughput topological structure determination of RNAs, guided by some experimental data are lacking. We present here a novel method (RS3D) that can assimilate the RNA secondary structure information, SAXS data, and any readily available tertiary contact information to determine the topological fold of RNA.Starting from an open conformation that satisfies the secondary structure information in a glob model, where each glob represents a specific nucleotide, the algorithm carries out natural hierarchical moves evident from the structural composition of RNAs. Every new move is guided towards satisfying the SAXS data fit, secondary structure constraints, and any additional long--range interaction information. The best--ranked glob models are then converted to explicit all--atom coordinates and refined against the SAXS data and solvent accessibility data (if available) under the constraints of robust force fields using the Xplor--NIH program. Our method is benchmarked with a variety of RNA folding architectures currently present in the structure database. Furthermore, we demonstrate the applicability and feasibility of the program to derive low resolution topological structures of relatively large multi--domain RNAs.
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