Search results for "nanoparticle"
showing 10 items of 2198 documents
Protocol for development of various plants leaves extract in single-pot synthesis of metal nanoparticles
2012
This article is aimed to extend a simple protocol for preparation of various plant leaves extract and their application to green synthesis of the metallic nanoparticles. Five plant leaves extract showed mild reduction and stabilization ability for silver and gold nanoparticles (AgNPs and AuNPs) at room temperature. The particle size range varied from 25 to 42 nm and 21 to 47 nm for AgNPs and AuNPs, respectively. Plant leaves extract-mediated nanoparticles were characterized to confirm the shape, size, crystallinity, and content using different spectroscopic investigations. Differences in stability of nanoparticles at different pH were also measured by zeta potential.
Cooperative Catechol-Functionalized Polypept(o)ide Brushes and Ag Nanoparticles for Combination of Protein Resistance and Antimicrobial Activity on M…
2018
Prevention of biofouling and microbial contamination of implanted biomedical devices is essential to maintain their functionality and biocompatibility. For this purpose, polypept(o)ide block copolymers have been developed, in which a protein-resistant polysarcosine (pSar) block is combined with a dopamine-modified poly(glutamic acid) block for surface coating and silver nanoparticles (Ag NPs) formation. In the development of a novel, versatile, and biocompatible antibacterial surface coating, block lengths pSar were varied to derive structure-property relationships. Notably, the catechol moiety performs two important tasks in parallel; primarily it acts as an efficient anchoring group to me…
A Simple Entropic-Driving Separation Procedure of Low-Size Silver Clusters, Through Interaction with DNA
2021
Abstract Synthesis and purification of metal clusters without strong binding agents by wet chemical methods are very attractive for their potential applications in many research areas. However, especially challenging is the separation of uncharged clusters with only a few number of atoms, which renders the usual techniques very difficult to apply. Herein, we report the first efficient separation of Ag2 and Ag3 clusters using the different entropic driving forces when such clusters interact with DNA, into which Ag3 selectively intercalates. After sequential dialysis of the samples and denaturalizing the DNA‐Ag3 complex, pure Ag2 can be found in the dialysate after extensive dialysis. Free Ag…
Silver Nanoparticles Affect Functional Bioenergetic Traits in the Invasive Red Sea Mussel
2016
We investigated the functional trait responses to 5 nm metallic silver nanoparticle (AgNPs) exposure in the Lessepsian-entry bivalve B. pharaonis. Respiration rate (oxygen consumption), heartbeat rate, and absorption efficiency were evaluated across an 8-day exposure period in mesocosmal conditions. Basal reference values from not-exposed specimens were statistically compared with those obtained from animals treated with three sublethal nanoparticle concentrations (2 μg L−1, 20 μg L−1, and 40 μg L−1). Our data showed statistically significant effects on the average respiration rate of B. pharaonis. Moreover, complex nonlinear dynamics were observed as a function of the concentration level a…
Laser-Ablation-Induced Synthesis of SiO2-Capped Noble Metal Nanoparticles in a Single Step
2010
Here we describe a simple, powerful technique based on the laser ablation of a target immersed in a water solution of a metal salt. With this method, nanoparticles of different metals and alloys can be processed very quickly. Both the target and the salt solution can be chosen to produce metal nanoparticles of different sizes, surface-oxidized nanoparticles (silica-silver, for example), or even more complex structures to be defined by the researcher on one or more steps because the technique combines the advantages of both physical and chemical methods. We have applied this technique to the fabrication of inert silica-metal (silver, gold, and silver-gold) nanoparticles with a strong surface…
Switchable Bactericidal Effects from Novel Silica-Coated Silver Nanoparticles Mediated by Light Irradiation
2011
Here we report on the triggering of antibacterial activity by a new type of silver nanoparticle coated with porous silica, Ag@silica, irradiated at their surface plasmon resonant frequency. The nanoparticles are able to bind readily to the surface of bacterial cells, although this does not affect bacterial growth since the silica shell largely attenuates the intrinsic toxicity of silver. However, upon simultaneous exposure to light corresponding to the absorption band of the nanoparticles, bacterial death is enhanced selectively on the irradiated zone. Because of the low power density used for the treatments, we discard thermal effects as the cause of cell killing. Instead, we propose that …
Atomic and electronic structure of gold clusters: understanding flakes, cages and superatoms from simple concepts.
2008
Atomic structure and electronic structure are intimately interrelated properties of nanoclusters and nanoparticles, defining their stability, electronic, optical and chemical properties, in other words, their usability as potential components for nanoscale devices. This tutorial review attempts to describe the development in understanding the structures of bare and ligand-protected gold clusters over the past decade, based on selected density-functional-theory calculations. This review should be of interest both to newcomers in the field and to an interdisciplinary community of researchers working in synthesis, characterization and utilization of ligand-protected gold clusters.
Development of a novel rapamycin loaded nano- into micro-formulation for treatment of lung inflammation
2022
AbstractIt has recently emerged that drugs such as the mTOR inhibitor rapamycin (Rapa) may play a key role in the treatment of airway inflammation associated with lung diseases, such as chronic obstructive pulmonary disease, asthma, and cystic fibrosis. Nevertheless, Rapa clinical application is still prevented by its unfavorable chemical-physical properties, limited oral bioavailability, and adverse effects related to non-specific biodistribution. In this paper, the design and production of a novel formulation of Rapa based on nano into micro (NiM) particles are detailed. To achieve it, Rapa-loaded nanoparticles were produced by nanoprecipitation of an amphiphilic pegylated poly-ɛ-caprolac…
Triple-target stimuli-responsive anti-COVID-19 face mask with physiological virus-inactivating agents
2021
Conventional face masks to prevent SARS-CoV-2 transmission are mostly based on a passive filtration principle. Ideally, anti-COVID-19 masks should protect the carrier not only by size exclusion of virus aerosol particles, but also be able to capture and destroy or inactivate the virus. Here we present the proof-of-concept of a filter mat for such a mask, which actively attracts aerosol droplets and kills the virus. The electrospun mats are made of polycaprolactone (PCL) a hydrophilic, functionalizable and biodegradable polyester, into which inorganic polyphosphate (polyP) a physiological biocompatible, biodegradable and antivirally active polymer (chain length, ∼40 Pi units) has been integr…
Biological tolerance of different materials in bulk and nanoparticulate form in a rat model: sarcoma development by nanoparticles
2006
In order to study the pathobiological impact of the nanometre-scale of materials, we evaluated the effects of five different materials as nanoparticulate biomaterials in comparison with bulk samples in contact with living tissues. Five groups out of 10 rats were implanted bilaterally for up to 12 months with materials of the same type, namely TiO 2 , SiO 2 , Ni, Co and polyvinyl chloride (PVC), subcutaneously with bulk material on one side of the vertebral column and intramuscularly with nanoparticulate material on the contralateral side. At the end of each implantation time, the site was macroscopically examined, followed by histological processing according to standard techniques. Malign…