Reference materials and representative test materials to develop nanoparticle characterization methods: the NanoChOp project case

Abstract

This paper describes the production and characteristics of the nanoparticle test materials prepared for common use in the collaborative research project NanoChOp (Chemical and optical characterization of nanomaterials in biological systems), in casu suspensions of silica nanoparticles and CdSe/CdS/ZnS quantum dots (QDs). This paper is the first to illustrate how to assess whether nanoparticle test materials meet the requirements of a “reference material” (ISO Guide 30, 2015) or rather those of the recently defined category of “representative test material (RTM)” (ISO/TS 16195, 2013). The NanoChOp test materials were investigated with small-angle X-ray scattering (SAXS), dynamic light scattering (DLS), and centrifugal liquid sedimentation (CLS) to establish whether they complied with the required monomodal particle size distribution. The presence of impurities, aggregates, agglomerates, and viable microorganisms in the suspensions was investigated with DLS, CLS, optical and electron microscopy and via plating on nutrient agar. Suitability of surface functionalization was investigated with attenuated total reflection Fourier transform infrared spectrometry (ATR-FTIR) and via the capacity of the nanoparticles to be fluorescently labeled or to bind antibodies. Between-unit homogeneity and stability were investigated in terms of particle size and zeta potential. This paper shows that only based on the outcome of a detailed characterization process one can raise the status of a test material to RTM or reference material, and how this status depends on its intended use.

A systematic comparison of different techniques to determine the zeta potential of silica nanoparticles in biological medium

“…One reason might be the differences in samples used in the different laboratories and at different points of time. However, the homogeneity and stability data provided with the test materials 13 are much smaller than the experimentally observed differences. For the purposes of the Fig.…”

“…This is due to the traces of acetic acid which was used to stabilise the aminated NPs. 13 For TRPS and z-PTA, the pH values of the more diluted dispersions were found to be closer to that of the dispersing media: about 5 for puried water (z-PTA) and about 7 for Tris-HCl buffer. Table 2 shows the summary of the z-potential results that were obtained with the three techniques.…”

“…13,14 The RTMs were produced in the context of the NEW03 NanoChOp project 15 of the European Metrology Research Programme aiming at the development of analytical methods for the assessment 13 of NPs in biological media. Both materials (NanoChOp-05, plain silica and NanoChOp-06, aminated silica) with a nominal sphere-equivalent hydrodynamic particle diameter of 82 nm, as measured by small-angle X-ray scattering (SAXS), were supplied in Ar-ushed and ame-sealed amber ampoules lled with 9 mL (NanoChOp-05) or with 2.5 mL (NanoChOp-06) of the aqueous suspensions of nominally 2.5 g kg À1 particle mass fraction.…”

Oligomeric structure and chaperone-like activity of Drosophila melanogaster mitochondrial small heat shock protein Hsp22 and arginine mutants in the alpha-crystallin domain

“…Up to moderately high temperatures, the DLS analysis detected only one single population with a relatively large polydispersity (around 40%). It is worth noticing that for globular and monodisperse proteins, the polydispersity is expected to be below 20% (Roebben et al 2015). For the DmHsp22WT, the percentage of polydispersity indicates a stable behavior of up to 55°C ranging from 39 to 44%.…”

“…They are found in all organisms including cyanobacterial viruses (Bourrelle-Langlois et al 2016;Maaroufi and Tanguay 2013). Small Hsps are expressed under various stress conditions as well as during development in a cell-specific pattern (Arrigo and Tanguay 1991;Marin et al 1993Michaud et al 1997;Michaud and Tanguay 2003;Morrow and Tanguay 2003, 2015. Their molecular weight vary between 12 and 43 kDa (Sudnitsyna et al 2012;Tyedmers et al 2010), and their primary structure is subdivided in three domains: an alpha-crystallin domain (ACD), flanked by a highly variable N-terminal sequence (NTS) and a C-terminal extension (CTE) (Basha et al 2012;Delbecq and Klevit 2013;Kappe et al 2010).…”