6 research outputs found
Rapid Kinetics of Size and pH-Dependent Dissolution and Aggregation of Silver Nanoparticles in Simulated Gastric Fluid
As silver nanoparticles (AgNPs) are
used in a wide array of commercial
products and can enter the human body through oral exposure, it is
important to understand the fundamental physical and chemical processes
leading to changes in nanoparticle size under the conditions of the
gastrointestinal (GI) tract. Rapid AgNP growth was observed using
nanoparticle tracking analysis with 30 s resolution over a period
of 17 min in simulated gastric fluid (SGF) to explore rapid kinetics
as a function of pH (SGF at pH 2, 3.5, 4.5 and 5), size (20 and 110
nm AgNPs), and nanoparticle coating (citrate and PVP). Growth was
observed for 20 nm AgNP at each pH, decreasing in rate with increasing
pH, with the kinetics shifting from second-order to first-order. The
110 nm AgNP showed growth at ≤3.5 pH, with no growth observed
at higher pH. This behavior can be explained by the generation of
Ag<sup>+</sup> in acidic environments, which precipitates with Cl<sup>–</sup>, leading to particle growth and facilitating particle
aggregation by decreasing their electrostatic repulsion in solution.
These results highlight the need to further understand the importance
of initial size, physicochemical properties, and kinetics of AgNPs
after ingestion to assess potential toxicity
Interlaboratory comparison of size measurements on nanoparticles using nanoparticle tracking analysis (NTA)
One of the key challenges in the field of nanoparticle (NP) analysis is in producing reliable and reproducible characterisation data for nanomaterials. This study looks at the reproducibility using a relatively new, but rapidly adopted, technique, Nanoparticle Tracking Analysis (NTA) on a range of particle sizes and materials in several different media. It describes the protocol development and presents both the data and analysis of results obtained from 12 laboratories, mostly based in Europe, who are primarily QualityNano members. QualityNano is an EU FP7 funded Research Infrastructure that integrates 28 European analytical and experimental facilities in nanotechnology, medicine and natural sciences with the goal of developing and implementing best practice and quality in all aspects of nanosafety assessment. This study looks at both the development of the protocol and how this leads to highly reproducible results amongst participants. In this study, the parameter being measured is the modal particle size