Antimicrobial resistance (AMR) is one of the biggest threats to the environment and health. AMR rapidly invalidates conventional antibiotics, and antimicrobial nanomaterials have been increasingly explored as alternatives. Interestingly, several antimicrobial nanomaterials show AMR-independent antimicrobial effects without detectable new resistance and have therefore been suggested to prevent AMR evolution. In contrast, some are found to trigger the evolution of AMR. Given these seemingly conflicting findings, a timely discussion of the two faces of antimicrobial nanomaterials is urgently needed. This review systematically compares the killing mechanisms and structure-activity relationships of antibiotics and antimicrobial nanomaterials. We then focus on nano-microbe interactions to elucidate the impacts of molecular initiating events on AMR evolution. Finally, we provide an outlook on future antimicrobial nanomaterials and propose design principles for the prevention of AMR evolution.

Antimicrobial resistance (AMR) is one of the biggest threats to the environment and health. AMR rapidly invalidates conventional antibiotics, and antimicrobial nanomaterials have been increasingly explored as alternatives. Interestingly, several antimicrobial nanomaterials show AMR‐independent antimicrobial effects without detectable new resistance and have therefore been suggested to prevent AMR evolution. In contrast, some are found to trigger the evolution of AMR. Given these seemingly conflicting findings, a timely discussion of the two faces of antimicrobial nanomaterials is urgently needed. This review systematically compares the killing mechanisms and structure‐activity relationships of antibiotics and antimicrobial nanomaterials. We then focus on nano‐microbe interactions to elucidate the impacts of molecular initiating events on AMR evolution. Finally, we provide an outlook on future antimicrobial nanomaterials and propose design principles for the prevention of AMR evolution.

An eco-friendly inhibitor L-valine (LV) in controlling corrosion of carbon steel in rain water in the absence and presence of Zn 2+ has been evaluated by mass loss method. The formulation consisting of 50 ppm of L-valine and 50 ppm of Zn 2+ offers good inhibition efficiency of 74%. When 50 ppm of sodium gluconate (SG) is added to the formulations consisting of 50 ppm of LV and 50 ppm of Zn 2+ , the inhibition efficiency increases from 74% to 98%. As the immersion period increases, the inhibition efficiency does not alter. Polarization study reveals that this formulation functions as a mixed inhibitor. AC impedance spectra reveal the presence of a protective film on the metal surface. The FTIR spectra study lead to the conclusion that the Fe 2+ -LV complex and Fe 2+ -SG complex formed on anodic sites of the metal surface controlled the anodic reaction and Zn(OH) 2 formed on the cathodic sites of the metal surface controlling the cathodic reaction. The Ecofriendly inhibitor Lvaline -Zn 2+ -SG system may find in cooling water system

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The electrochemical behavior of N-methyl- and N-benzyl-4-piperidone curcumin analogs were studied experimentally and theoretically. The studied compounds present different substituents at the para position in the phenyl rings (-H, -Br, -Cl, -CF3, and -OCH3). We assessed their electrochemical behavior by differential pulse and cyclic voltammetry, while we employed density functional theory (DFT) M06 and M06-2x functionals along with 6-311+G(d,p) basis set calculations to study them theoretically. The results showed that compounds suffer a two-electron irreversible oxidation in the range of 0.72 to 0.86 V, with surface concentrations ranging from 1.72 × 10−7 to 5.01 × 10−7 mol/cm2. The results also suggested that the process is diffusion-controlled for all compounds. M06 DFT calculations showed a better performance than M06-2x to obtain oxidation potentials. We found a good correlation between the experimental and theoretical oxidation potential for N-benzyl-4-piperidones (R2 = 0.9846), while the correlation was poor for N-methyl-4-piperidones (R2 = 0.3786), suggesting that the latter suffer a more complex oxidation process. Calculations of the BDEs for labile C-H bonds in the compounds suggested that neither of the two series of compounds has a different tendency for a proton-coupled electron transfer (PCET) oxidation process. It is proposed that irreversible behavior is due to possible dimerization of the compounds by Shono-type oxidation.