Nanoparticles as a younger member of the trace element species family - a food perspective

Abstract

Speciation analysis plays a key role in understanding the biological activity and toxicity of an element. So far, classical speciation analysis focused only on the dissolved fraction of an elemental species, whereas nanoparticle forms of analytes are being widely found in consumer and industrial products. A significant contributor to human exposure to nanoparticles is through food into which nanoparticles can be incorporated from endogenous sources or they may be formed naturally in the living organisms. Nanoparticles often undergo changes in the food matrices and upon consumption, in the gastrointestinal tract, which present a significant challenge to their characterisation. Therefore, a combination of both classical and nanoparticle speciation analytical techniques is needed for the characterisation of both dissolved and particulate forms of the chemical species. This article presents and discusses the current trends in analysis of nanoparticle behaviour in the gastrointestinal tract and formation and characterisation of biogenic nanoparticles.

Keywords: Biogenic; Dissolution; Food; Gastrointestinal tract; Nanoparticles; Speciation.

Fig. 1

An overview of NP sources in food (a), matrix-driven changes to NP properties (b), and most used techniques for NP analysis (c) (spICP-MS, single-particle inductively coupled plasma mass spectrometry; FFF-ICP-MS, field flow fractionation ICP-MS; SEC–ICP–MS, size exclusion chromatography ICP-MS; HDC-ICP-MS, hydrodynamic chromatography ICP-MS; Cy-TOF, cytometry time of flight; TEM, transmission electron microscopy; SEM, scanning electron microscopy; EDF-HSI, enhanced dark-field hyperspectral imaging; XRF, X-ray fluorescence; TXM, transmission X-ray microscopy; LA-ICP-MS, laser ablation ICP-MS; nanoSIMS, nanoscale secondary ion mass spectrometry)

Fig. 2

Investigation of the dissolution of 20 and 50 nm Ag NPs spiked to bovine serum albumin (BSA) solution at room temperature by AF4-ICP-MS: a fractograms based on quantified ICP-MS signal, b relative fraction of Ag in NP form and bound to BSA (unpublished results)

Fig. 3

Energy-dispersive x-ray emission spectra of nanosized particles in lysosomes of Ag acetate exposed rats (red line) and corresponding background spectra (black line), i.e. spectra of surrounding tissue containing no visible particles (unstained sections). The osmium signal originated from the tissue fixation procedure in which osmium tetroxide was used as a post-fixative. The TEM image shows the analysed particle-containing area. Originally published in [36]