High-entropy alloys (HEAs) are attracting intensive attention due to their broad compositional tunability and interesting catalytic properties. However, precisely shaping the HEAs into suprathin low-dimensional nanostructures for achieving diverse applications remains an enormous challenge owing to their intrinsic thermodynamic instability. Herein we propose a new and general low-temperature method for incorporating up to eight metallic elements into one single-phase subnanometer ribbon to achieve the thinnest HEA metal materials in the world. We experimentally demonstrate that synthetic processes for suprathin HEA subnanometer ribbons (SNRs) include (1) different metal atom nucleation via galvanic exchange reaction between different metal precursors and Ag nanowire template, (2) co-reduction of different metal precursors on nanowire template, and (3) the removal of the inner Ag core. Density functional theory (DFT) calculations reveal that the crystallization and stabilization of HEA SNRs strongly depend on the “highly dynamic” Ag from the template, and the crystallization levels of HEA subnanometer ribbons are closely correlated with the concentration of Pt and Pd. We demonstrate that the present synthetic method enables the flexible control of components and concentrations in HEAs SNRs for achieving a library of HEA SNRs and also superior electrocatalytic properties. The well-designed HEA SNRs show great improvement in catalyzing the oxygen reduction reaction of fuel cells and also high discharge capacity, low charge overpotential, and excellent durability for Li–O2 batteries. DFT calculations reveal the superior electrochemical performances are attributed to the strong reduction capability from high-concentration reductive elements in HEAs, while the other elements guarantee the site-to-site efficient electron transfer.

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The emergence of plasmid-mediated New Delhi metallo-β-lactamase-1 (NDM-1) in carbapenem-resistant Gramnegative pathogens is an increasing clinical threat. Here we report the discovery of an NDM-1 inhibitor, magnolol, through enzyme inhibition screening. We showed that magnolol significantly inhibited NDM enzyme activity (IC 50 = 6.47 µg/mL), and it restored the activity of meropenem against Escherichia coli ZC-YN3, an NDM-1-producing E. coli isolate, in in vitro antibacterial activity assays. Magnolol lacked direct antibacterial activity, but compared with meropenem alone, it reduced the MICs of meropenem against E. coli ZC-YN3 by 4-fold and killed almost all the bacteria within 3 h. Molecular modeling and a mutational analysis demonstrated that magnolol binds directly to the catalytic pocket (residues 110 to 200) of NDM-1, thereby blocking the binding of the substrate to NDM-1 and leading to its inactivation. Our results demonstrate that the combination of magnolol and meropenem may have the potential to treat infections caused by NDM-1-positive, carbapenem-resistant Gram-negative pathogens.

We characterized the synergistic effect produced between pterostilbene and polymyxin B (fractional inhibitory concentration [FIC] index = 0.156 or 0.188) against MCR-producing strains of both human and animal origins. The time-killing assays showed that either pterostilbene or polymyxin B failed to eradicate the- and NDM-positive strain ZJ487, but the combination eliminated the strain by 1 h postinoculation. The survival rate of mice after intraperitoneal infections was significantly enhanced from 0% to 60% in the group in which combination therapy was applied.

Background and PurposeBacteria producing New Delhi metallo‐β‐lactamase‐1 (NDM‐1) are an increasing clinical threat. NDM‐1 can inactivate almost all β‐lactams and is not sensitive to any existing β‐lactamase inhibitors. To identify effective inhibitors of the NDM‐1 enzyme and clarify the mechanism of action, a “lead compound” for developing more potent NDM‐1 inhibitors needs to be provided.Experimental ApproachNatural compounds were tested by enzyme inhibition screening to find potential inhibitors. MIC assays, growth curve assays, and time‐kill assays were conducted to evaluate the in vitro antibacterial activity of pterostilbene and the combination of pterostilbene and meropenem. A murine thigh model and a mouse pneumonia model were used to evaluate the in vivo efficacy of combined therapy. Molecular modelling and a mutational analysis were used to clarify the mechanism of action.Key ResultsPterostilbene significantly inhibited NDM‐1 hydrolysis activity in enzyme inhibition screening assays and effectively restored the effectiveness of meropenem in vitro with NDM‐expressing isolates in antibacterial activity assays. In addition, the combined therapy effectively reduced the bacterial burden in a murine thigh model and protected mice from pneumonia caused by Klebsiella pneumoniae. By means of molecular dynamics simulation, we observed that pterostilbene localized to the catalytic pocket of NDM‐1, hindering substrate binding to NDM‐1 and reducing NDM‐1 activity.Conclusions and ImplicationsThese findings indicated that pterostilbene combined with meropenem may offer a new safe and potential “lead compound” for the further development of NDM‐1 inhibitors.