Differential Pd-nanocrystal facets demonstrate distinct antibacterial activity against Gram-positive and Gram-negative bacteria

Abstract

Noble metal-based nanomaterials have shown promise as potential enzyme mimetics, but the facet effect and underlying molecular mechanisms are largely unknown. Herein, with a combined experimental and theoretical approach, we unveil that palladium (Pd) nanocrystals exhibit facet-dependent oxidase and peroxidase-like activities that endow them with excellent antibacterial properties via generation of reactive oxygen species. The antibacterial efficiency of Pd nanocrystals against Gram-positive bacteria is consistent with the extent of their enzyme-like activity, that is {100}-faceted Pd cubes with higher activities kill bacteria more effectively than {111}-faceted Pd octahedrons. Surprisingly, a reverse trend of antibacterial activity is observed against Gram-negative bacteria, with Pd octahedrons displaying stronger penetration into bacterial membranes than Pd nanocubes, thereby exerting higher antibacterial activity than the latter. Our findings provide a deeper understanding of facet-dependent enzyme-like activities and might advance the development of noble metal-based nanomaterials with both enhanced and targeted antibacterial activities.

Construction of Nanozyme‐Hydrogel for Enhanced Capture and Elimination of Bacteria

“…Therefore, great efforts have been devoted to developing alternative antibacterial materials in recent years . Particularly, inspired by natural enzymes for damaging bacteria through catalyzing the production of harmful reactive oxygen species (ROS), researchers diverted their attention to the construction of artificial enzymes with the functions of natural enzymes to combat bacteria . Different from high‐cost and instable natural enzymes, nanozymes are generally facile‐preparation and stable.…”

Revealing the Intrinsic Peroxidase-Like Catalytic Mechanism of Heterogeneous Single-Atom Co–MoS2

“…The atomistic-level exploration of the original active sites of nanozymes is mainly performed by simplifying the singlecomponent catalysts of noble metal nanoparticles [8][9][10], transition metal oxides [11], and carbon-based materials [12,13]. The cascade reactions catalyzed by multiple enzymes in an organism provide great impetus for preparing composite catalysts by integrating different kinds of nanozymes to mimic the complexity of biocatalysis [14,15].…”

Multi-hierarchical Profiling the Structure-Activity Relationships of Engineered Nanomaterials at Nano-Bio Interfaces

“…Our study successfully achieved tiered view of the nano-SARs of Fe 2 O 3 particles in THP-1 cells, providing substantial new insights for tailored design of ENMs by modifying their physicochemical properties to acquire desired bio-effects. This allows us to reduce the toxicities of some hazardous ENMs 7, 8, 28 , or enhance the effects of nanomedicine 5, 6, 39 . Besides of Fe 2 O 3 , the multi-hierarchical nano-SAR assessment method could be potentially extended to other ENMs.…”

“…Given the rapidly increasing number of ENMs as well as their diverse physicochemical properties including size, shape, surface area, surface reactivity, mechanical strength, etc. 2 , the in vitro structure-activity relationship (SAR) studies on ENMs have significantly promoted the development of nanobiotechnology 3-5 . In general, nano-SAR analyses have enabled the determination of the key physicochemical properties of ENMs that are responsible for evoking a target bio-effect in the organism 1, 6 , allowed bio-hazard ranking of various new ENMs 7 , and facilitated the engineering design of biocompatible materials by tailored functionalization 8 .…”