Efficacy and safety of nanohybrids comprising silver nanoparticles and silicate clay for controlling Salmonella infection.
Ontology highlight
ABSTRACT:
SUBMITTER: Chiao SH
PROVIDER: S-EPMC3363949 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:We develop a novel nanohybrid showing a strong antibacterial activity on all of the tested pathogens, including methicillin-resistant Staphylococcus auerus and silver-resistant E. coli. The nanohybrid consists of silver nanoparticles (AgNPs) supported on 1 nm-thick silicate platelets (NSPs). The AgNP/NSP nanohybrid enables to encapsulate bacteria and triggers death signals from the cell membrane. The geographic shape of the NSPs concentrates AgNPs but impedes their penetration into attached cells, mitigating the detrimental effect of silver ion deposition in applied tissues. Moreover, the tightly tethered AgNPs on NSP surface achieve a stronger biocidal effect than silver nitrate, but bypassing Ag(+) mechanism, on silver-resistant bacteria. This nanohybrid presents an effective and safe antimicrobial agent in a new perspective.
| S-EPMC3117870 | biostudies-literature
Project description:Impact of silver and silver nanoparticles on the structure and functionality of microbial communities in sewage treatment plants
| PRJEB20907 | ENA
Project description:The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains a severe health threat. The COVID-19 infections occurring in humans and animals render human-animal interfaces hot spots for spreading the pandemic. Lessons from the past point towards the antiviral properties of copper formulations; however, data showing the "contact-time limit" surface inhibitory efficacy of copper formulations to contain SARS-CoV-2 are limited. Here, we show the rapid inhibition of SARS-CoV-2 after only 1 and 5 min on two different surfaces containing copper-silver (Cu-Ag) nanohybrids. We characterized the nanohybrids' powder and surfaces using a series of sophisticated microscopy tools, including transmission and scanning electron microscopes (TEM and SEM) and energy-dispersive X-ray spectroscopy (EDX). We used culturing methods to demonstrate that Cu-Ag nanohybrids with high amounts of Cu (~65 and 78 wt%) and lower amounts of Ag (~7 and 9 wt%) inhibited SARS-CoV-2 efficiently. Collectively, the present work reveals the rapid SARS-CoV-2 surface inhibition and the promising application of such surfaces to break the SARS-CoV-2 transmission chain. For example, such applications could be invaluable within a hospital or live-stock settings, or any public place with surfaces that people frequently touch (i.e., public transportation, shopping malls, elevators, and door handles) after the precise control of different parameters and toxicity evaluations.
| S-EPMC8308209 | biostudies-literature
Project description:We have investigated particle size, interior structure, drug release kinetics, and anticancer efficacy of PEG-b-PLGA-based nanoparticles loaded with a series of paclitaxel (PTX)-silicate prodrugs [PTX-Si(OR)3]. Silicate derivatization enabled us to adjust the hydrophobicity and hydrolytic lability of the prodrugs by the choice of the alkyl group (R) in the silicate derivatives. The greater hydrophobicity of these prodrugs allows for the preparation of nanoparticles that are stable in aqueous dispersion even when loaded with up to ca. 75 wt % of the prodrug. The hydrolytic lability of silicates allows for facile conversion of prodrugs back to the parent drug, PTX. A suite of eight PTX-silicate prodrugs was investigated; nanoparticles were made by flash nanoprecipitation (FNP) using a confined impingement jet mixer with a dilution step (CIJ-D). The resulting nanoparticles were 80-150 nm in size with a loading level of 47-74 wt % (wt %) of a PTX-silicate, which corresponds to 36-59 effective wt % of free PTX. Cryogenic transmission electron microscopy images show that particles are typically spherical with a core-shell structure. Prodrug/drug release profiles were measured. Release tended to be slower for prodrugs having greater hydrophobicity and slower hydrolysis rate. Nanoparticles loaded with PTX-silicate prodrugs that hydrolyze most rapidly showed in vitro cytotoxicity similar to that of the parent PTX. Nanoparticles loaded with more labile silicates also tended to show greater in vivo efficacy.
| S-EPMC4729777 | biostudies-literature
Project description:The widespread use of silver nanoparticles (Ag NPs) has raised substantial health risks to environmental and human beings. Although various negative effects had been reported, little is known about the epigenetic toxicity induced by Ag+ and Ag NPs. This study characterized physiological and lncRNA profiles to explore the toxic effects and epigenetic mechanisms in Tetrahymena thermophila on exposure to Ag+ and three types of Ag NPs. We found that both of Ag+ and Ag NPs exhibited strong growth-inhibiting effects on T. thermophila. The toxicity was mainly caused by high levels of reactive oxygen species (ROS), which subsequently led to lipid peroxidation and mitochondrial dysfunction. As a defense mechanism against oxidative stress, the protist elicited an antioxidant response. Importantly, 1250 lncRNAs were differentially expressed under Ag+ or Ag NPs exposure relative to the non-exposure control, which were clustered into 15 expression modules in weighted gene co-expression network analysis. These gene modules exhibited toxicant-specific expression patterns, indicating that they play various regulatory roles, including cell growth inhibition, cell membrane cation channel activation, and oxidoreductase activity promotion. Taken together, this research illuminates how post-transcriptional mechanisms of a ciliated protozoa regulate responses to Ag+ and Ag NPs toxicities.
2021-09-10 | GSE157616 | GEO
Project description:Clays are multi-layered inorganic materials that can be used to prepare nanocomposite fillers. Because the multi-layered structure is thermodynamically stable, it is difficult to change a multi-layered material into single layers to improve its dispersity. Previously, clays were modified with dodecylammonium cations to promote complexation with nylon 6, nylon 66, polypropylene, polyethylene, polystyrene, and polycaprolactone to increase the mechanical strength (and/or thermal stability) of the composite material; however, complete exfoliation could not be achieved in these composites. In this study, pillar[5]arenes are synthesized and functionalized with ten cationic substituents as novel intercalants for modifying bentonite clay, which is a multi-layered metal-cation-containing silicate. The pillar[5]arenes exfoliate the clay by forming polyrotaxanes with poly(ethylene glycol) through host-guest interactions.
| S-EPMC8137868 | biostudies-literature
Project description:Antibiotic-resistant bacteria are becoming a serious threat to public health worldwide. To address this problem, we have developed multifunctional peptide (MFP)-coated silver nanoparticles (MFP@AgNPs) for antibacterial studies. MFPs, which can physically adsorb to AgNPs via electrostatic interactions are comprised of a matrix metalloproteinase (MMP) cleavable sequence (PVGLIG), an antimicrobial peptide (tachyplesin-1), and a target peptide (PGP-PEG). The resulting MFP@AgNPs were characterized by various technologies, including UV-vis spectrophotometry, zeta potential analyzer, circular dichroism (CD) spectroscopy, attenuated total reflection-Fourier-transform infrared spectroscopy (ATR-FTIR), and transmission electron microscopy (TEM). The MIC and MBC were investigated against both Gram-positive bacteria and Gram-negative bacteria. The antibacterial activity in vivo was evaluated on MDR-AB (multidrug-resistant Acinetobacter baumannii) infected mice. We found that MFP@AgNPs exhibited antibacterial activity against both Gram-positive bacteria and Gram-negative bacteria. Compared to bare AgNPs, MFP@AgNPs-1 killed MDR-AB faster and more efficiently. SEM images showed that MFP@AgNPs-1 induced cell disruption via cell membrane damage. In vivo studies further confirmed the enhanced antibacterial activity against MDR-AB infections. The developed MFP@AgNPs-1 reduced the cytotoxicity of AgNPs and enhanced the antibacterial activity against MDR-AB in vitro and in vivo, providing a possible solution against multidrug-resistant bacterial infections.
| S-EPMC9057333 | biostudies-literature
Project description:Modifying the surfaces of metal nanoparticles with self-assembled monolayers of functionalized thiols provides a simple and direct method to alter their surface properties. Mixed self-assembled monolayers can extend this approach since, in principle, the surfaces can be tuned by altering the proportion of each modifier that is adsorbed. However, this works best if the composition and microstructure of the monolayers can be controlled. Here, we have modified preprepared silver colloids with binary mixtures of thiols at varying concentrations and modifier ratios. Surface-enhanced Raman spectroscopy was then used to determine the effect of altering these parameters on the composition of the resulting mixed monolayers. The data could be explained using a new model based on a modified competitive Langmuir approach. It was found that the composition of the mixed monolayer only reflected the ratio of modifiers in the feedstock when the total amount of modifier was sufficient for approximately one monolayer coverage. At higher modifier concentrations the thermodynamically favored modifier dominated, but working at near monolayer concentrations allowed the surface composition to be controlled by changing the ratios of modifiers. Finally, a positively charged porphyrin probe molecule was used to investigate the microstructure of the mixed monolayers, i.e., homogeneous versus domains. In this case the modifier domains were found to be <2 nm.
| S-EPMC3614020 | biostudies-literature
Project description:As the threat of antimicrobial-resistant bacteria compromises the safety and efficacy of modern healthcare practices, the search for effective treatments is more urgent than ever. For centuries, silver (Ag) has been known to have antibacterial properties and, over the past two decades, Ag-based nanoparticles have gained traction as potential antimicrobials. The antibacterial efficacy of Ag varies with structure, size, and concentration. In the present study, we examined Ag nanoparticles (AgNPs) for their antimicrobial activity and safety. We compared different commercially-available AgNPs against gram-negative Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, and gram-positive Staphylococcus aureus methicillin-resistant and susceptible strains. The most effective formula of AgNPs tested had single-digit (μg/mL) minimum inhibitory concentrations against gram-negative multidrug-resistant clinical bacterial isolates with novel and emerging mechanisms of resistance. The mode of killing was assessed in E. coli and was found to be bactericidal, which is consistent with previous studies using other AgNP formulations. We evaluated cytotoxicity by measuring physiological readouts using the Caenorhabditis elegans model and found that motility was affected, but not the lifespan. Furthermore, we found that at their antibacterial concentrations, AgNPs were non-cytotoxic to any of the mammalian cell lines tested, including macrophages, stem cells, and epithelial cells. More interestingly, our experiments revealed synergy with clinically relevant antibiotics. We found that a non-toxic and non-effective concentration of AgNPs reduced the minimum inhibitory concentrations of aminoglycoside by approximately 22-fold. Because both aminoglycosides and Ag are known to target the bacterial ribosome, we tested whether Ag could also target eukaryotic ribosomes. We measured the rate of mistranslation at bactericidal concentration and found no effect, indicating that AgNPs are not proteotoxic to the host at the tested concentrations. Collectively, our results suggest that AgNPs could have a promising clinical application as a potential stand-alone therapy or antibiotic adjuvants.
| S-EPMC9927651 | biostudies-literature
Project description:Metallic nanoparticles (NPs) especially silver (Ag) NPs have shown immense potential in medical applications due to their distinctive physio-chemical and biological properties. This article reports the conjugation of Ag NPs with Rubus fairholmianus extract. The modification of Ag NPs was confirmed using various physico-chemical characterization techniques. The cytotoxic effect of Rubus-conjugated Ag NPs (RAgNPs) was studied by LDH assay and proliferation by ATP assay. The apoptotic inducing ability of the NPs were investigated by Annexin V/PI staining, caspase 3/7 analysis, cytochrome c release, intracellular ROS analysis, Hoechst staining and mitochondrial membrane potential analysis using flow cytometry. The expression of apoptotic proteins caspase 3, Bax and P53 were analyzed using ELISA and caspase 3, Bax using western blotting. Cells treated with 10 µg/mL RAgNPs showed an increased number of cell death by microscopic analysis compared to untreated control cells. The RAgNPs induced a statistically significant dose-dependent decrease in proliferation (p < 0.001 for 5 and 10 µg/mL) and increased cytotoxicity in MCF-7 cells. A 1.83 fold increase in cytotoxicity was observed in cells treated with 10 µg/mL (p < 0.05) compared to the untreated cells. Nuclear damage and intracellular ROS production were observed upon treatment with all tested concentrations of RAgNPs and the highest concentrations (5 and 10 µg/mL) showed significant (p < 0.05, p < 0.01) expression of caspase 3, Bax and P53 proteins. The data strongly suggest that RAgNPs induces cell death in MCF-7 cells through the mitochondrial-mediated intrinsic apoptosis pathway. The present investigation supports the potential of RAgNPs in anticancer drug development.
| S-EPMC6156419 | biostudies-literature