Enhanced Antimicrobial Activity and Low Phytotoxicity of Acoustically Synthesized Large Aspect Ratio Cu-BTC Metal–Organic Frameworks with Exposed Metal Sites

Abstract

Metal−organic frameworks (MOFs) have recently been shown to be effective antimicrobial agents, particularly if they comprise pathogenicidal metal ions. Nevertheless, the accessibility of these active metal sites to the pathogen, and hence the MOFs' antimicrobial activity itself, is often poor since the metal nodes are usually embedded deep within its three-dimensional (3D) structure. We show that a unique copper-based (copper(II)-benzene-1,3,5-tricarboxylate) MOF, whose quasi-two-dimensional (quasi-2D) swordlike structure facilitates exposure of the metal ions along its surface, exhibits enhanced antimicrobial properties against three representative plant pathogens: a bacterium (Pseudomonas syringae), a fungus (Fusarium solani), and a virus (Odontoglossum ringspot virus (ORSV)). Such superior antimicrobial activity results in low minimum inhibitory concentrations (MICs)half that of a commercial pesticide and an eighth of its conventional 3D cubic MOF counterpart (HKUST-1)and hence low phytotoxicity, which can be attributed to the accessibility of the surface copper sites to the pathogen, thereby facilitating their adhesion and physical contact with the MOF. Additionally, we observed that orchids treated with the quasi-2D MOF showed negligible phytotoxicity and 80% decreased viral load. This work constitutes the first study to demonstrate the antimicrobial properties of this novel MOF against bacterial, fungal, and viral plant pathogens, and the first chemical control of ORSV.

Integrated Microsystem Toward High‐Throughput Automated Green Synthesis and Raman Enhancement Performance Screening of Noble‐Metal@Cu‐MOF

“…Moreover, the primary XRD diffraction peaks of Cu‐MOF were corresponding to (020), (121), (13$\[\bar{1}\]$), and (140) planes, respectively. [ 34,48 ] We further recorded the growth process of MNPs@Cu‐MOF with ultrasound by choosing AgNPs as the model nanoparticles as the results shown in Figure 2C. The entire reaction solution changed to yellow due to the introduction of AgNPs into this synthesis system.…”

Cost-Effective Screening of Antimicrobial Performance of Multiple Metal–Organic Frameworks via a Droplet-Based Batch Synthesis Platform

“…In addition, compared to the polyhedral Cu-MOFs, the rod-like structures (Zn-MOFs and Co-MOFs) facilitate exposure of the metal ions along their surface, which further enhances the antimicrobial performance. 33 Moreover, previous work has explained the best antimicrobial property of Co-MOFs that the different nature of metal types, coordination modes, and chemical stability leads to the differences in antimicrobial performance. 34 In other words, the polarity of the Co 2+ ions can be reduced via chelation and thus enhances the lipophilicity toward bacterial membranes, reaching the high antimicrobial property through structural changes in the bacterial cell wall.…”

“…However, the Cu-MOF does not exhibit obvious decomposition and collapse under the same experimental conditions. In addition, compared to the polyhedral Cu-MOFs, the rod-like structures (Zn-MOFs and Co-MOFs) facilitate exposure of the metal ions along their surface, which further enhances the antimicrobial performance . Moreover, previous work has explained the best antimicrobial property of Co-MOFs that the different nature of metal types, coordination modes, and chemical stability leads to the differences in antimicrobial performance .…”

Virus Management Using Metal–Organic Framework-Based Technologies

“…Indeed, the antiviral activity of pristine Cu-BTC (or HKUST-1) crystallized under two shapes�swordlike crystals and cubic crystals, neither being isomorphs�was assessed against odontoglossum ringspot virus (ORSV) infecting orchid cymbidium plants. 29 Using scanning electron microscopy (SEM), Marqus et al characterized the sizes and morphologies of both crystal shapes. The swordlike crystals were quasi-two-dimensional (quasi-2D) in morphology and their sizes were of several micrometers, whereas the cubic crystals were of an obviously cubic and three-dimensional (3D) morphology and were ∼40 μm in size.…”