Nanoparticles are released in the environment causing a negative impact in several ecosystems such as microbial communities. To adapt to environmental changes some bacteria use a collective behaviour ruled by a cell-to-cell communication process called quorum sensing (QS). In this study, the impact of some of the most employed metal-based nanoparticles, such as zinc oxide nanoparticles (ZnONPs), titanium dioxide nanoparticles (TiONPs) and silver nanoparticles (AgNPs) on bacterial QS has been assessed by using two different strains of the model organism Chromobacterium violaceum and by employing different experimental conditions. TiONPs were tested with and without applying a previous step of UV-irradiation while the effect of AgNPs of two diameter sizes (40 and 60 nm) and two different coating agents (PVP and citrate) was evaluated. Results evidenced that all nanoparticles produced a significant effect on violacein production and therefore, in the QS system. ZnONPs mainly disrupted the QS steps related to signal perception and response whereas TiONPs and AgNPs affected the autoinducer biosynthesis. AgNPs with the smallest size and citrate as capping agent produced the most deleterious effect while the impact of TiONPs was not affected by UV irradiation. The present study provides new insights into the mechanisms by which these commonly employed metal-based nanoparticles disturb bacterial QS-based communication and clearly evidences the potential risk of releasing nanoparticles to the environment, especially for microbial communities which play a key role in many environmental and technological processes.
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http://dx.doi.org/10.1016/j.scitotenv.2019.133869 | DOI Listing |
Small
January 2025
School of Materials Science and Engineering, Tianjin Key Laboratory of Composite and Functional Materials Key Laboratory of Advanced Ceramics and Machining Technology (Ministry of Education), Tianjin University, Tianjin, 300072, China.
Enhancing the catalytic performance and durability of M-N─C catalyst is crucial for the efficient operation of proton exchange membrane fuel cells (PEMFCs) and Zn-Air batteries (ZABs). Herein, an approach is developed for the in situ fabrication of a MOFs-derived porous carbon material, co-loaded with Co nanoparticles (NPs) and Co-N sites and integrated onto Fe-doped carbon nanotubes (CNTs), named Co-NC/Fe-NCNTs. Incorporating polymer-wrapped CNTs improves MOFs dispersion annealing at high temperature, which amplifies the three-phase boundary (TPB) by generating much more mesopores and exposing additional active sites within the catalysts layer.
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December 2024
National & Local Joint Engineering Research Center on Biomass Resource Utilization, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, P. R. China.
The cleavage and functionalization of carbon-carbon bonds are crucial for the reconstruction and upgrading of organic matrices, particularly in the valorization of biomass, plastics, and fossil resources. However, the inherent kinetic inertness and thermodynamic stability of C-C σ bonds make this process challenging. Herein, we fabricated a glucose-derived defect-rich hierarchical porous carbon as a heterogeneous catalyst for the oxidative cleavage and esterification of C(CO)-C bonds.
View Article and Find Full Text PDFEvid Based Dent
January 2025
Doctoral Research Fellow and Specialty Trainee (Endodontics), School of Dental Sciences, Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne, UK.
Aims: This study aimed to assess the effectiveness of a novel antimicrobial gel, containing copper and silver nanoparticles, for use in root canal disinfection.
Methods: Copper and silver-based gels were created in-house, using a support network of biocompatible polymers, including polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), and polyethylene glycol (PEG). Six experimental groups were created, three containing silver ions and three copper ions, where the PVA, PVP and PEG ratios were also adjusted in each group to test the gel's physical state.
Molecules
December 2024
School of Biological and Chemical Engineering, Nanyang Institute of Technology, Nanyang 473004, China.
Nickel disulfide (NiS) nanoparticles are encapsulated within nitrogen and sulfur co-doped carbon nanosheets, which are grown onto carbon nanofibers to form an array structure (NiS/C@CNF), resulting in a self-supporting film. This encapsulated structure not only prevents the agglomeration of NiS nanoparticles, but also memorably buffers its volume changes during charge/discharge cycles, thereby maintaining structural integrity. The nitrogen and sulfur co-doping enhances electronic conductivity and facilitates the faster ion transport of the carbon backbone, improving the low conductivity of the NiS/C@CNF anodes.
View Article and Find Full Text PDFSmall
January 2025
Department of Burns, The First Hospital Affiliated of Anhui Medical University, Anhui Medical University, Hefei, Anhui, 230032, P. R. China.
Bacterial infections are a significant obstacle to the healing of acute and chronic wounds, such as diabetic ulcers and burn injuries. Traditional antibiotics are the primary treatment for bacterial infections, but they present issues such as antibiotic resistance, limited efficacy, and potential side effects. This challenge leads to the exploration of nanozymes as alternative therapeutic agents.
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