Exploring LA-ICP-MS as a quantitative imaging technique to study nanoparticle uptake in Daphnia magna and zebrafish (Danio rerio) embryos

Abstract

The extent and the mechanisms by which engineered nanoparticles (ENPs) are incorporated into biological tissues are a matter of intensive research. Therefore, laser ablation coupled to inductively coupled plasma mass spectrometry (LA-ICP-MS) is presented for the detection and visualization of engineered nanoparticles (Al2O3, Ag, and Au) in ecotoxicological test organisms (Danio rerio and Daphnia magna). While ENPs are not taken up by the zebrafish embryo but attach to its chorion, incorporation into the gut of D. magna is clearly visible by a 50-μm spot ablation of 40-μm-thick organism sections. During laser ablation of the soft organic matrix, the hard ENPs are mobilized without a significant change in their size, leading to decreasing sensitivity with increasing size of ENPs. To compensate for these effects, a matrix-matched calibration with ENPs of the same size embedded in agarose gels is proposed. Based on such a calibration, the mass of ENPs within one organism section was calculated and used to estimate the total mass of ENPs per organism. Compared to the amount determined after acid digestion of the test organisms, recoveries of 20–100 % (zebrafish embryo (ZFE)) and of 4–230 % (D. magna) were obtained with LODs in the low ppm range. It is likely that these differences are primarily due to an inhomogeneous particle distribution in the organisms and to shifts in the particle size distribution from the initial ENPs to those present in the organism. It appears that quantitative imaging of ENPs with LA-ICP-MS requires knowledge of the particle sizes in the biological tissue under study.Electronic supplementary materialThe online version of this article (doi:10.1007/s00216-015-8720-4) contains supplementary material, which is available to authorized users.

Effect propagation after silver nanoparticle exposure in zebrafish (Danio rerio) embryos: a correlation to internal concentration and distribution patterns

“…Both the exact parameters for the transformation into a 2D-color plot and the LOD of the applied semi-quantitative LA-ICP-MS technique (35.7 fg Ag/50 μm spot) were reported earlier. 14…”

Fabrication of homogenous three‐dimensional biomimetic tissue for mass spectrometry imaging

“…With respect to drugs or other exogenous analytes, “on‐tissue” or “under‐tissue” micropipetting strategies are also difficult to accurately reflect the similar drug status within native tissue, where desorption/ionization is being processed under the complicated suppression by cells and extracellular matrix (ECM). Apart from parallel cryo‐sections, tissue homogenate is another type of surrogate used for representing the analyte's surrounding environment . Compared with standard‐spiked native tissue sections, analytes have much more in‐depth incorporation and uniform distribution .…”

“…Apart from parallel cryo-sections, tissue homogenate is another type of surrogate used for representing the analyte's surrounding environment. [26][27][28][29][30][31][32][33] Compared with standard-spiked native tissue sections, analytes have much more in-depth incorporation and uniform distribution. 34,35 Unfortunately, cells can seldomly survive under this violent homogenization process, 35 whereas the existence of cells should also contribute as the real impact factor for the analyte's desorption/ionization.…”

Elemental imaging (LA-ICP-MS) of zebrafish embryos to study the toxicokinetics of the acetylcholinesterase inhibitor naled

“…Mass spectrometry imaging for localizing chemicals in the zebrafish embryo has been performed only recently in a few studies with lipids and exogenous compounds (e.g., cocaine, copper) and nanoparticles [10, 13–15]. The most reproducible quantitative results in MS bioimaging can be obtained with laser ablation (LA) ICP-MS [16] which was applied in the past years to study distributions of natural elements [17–21] or elemental contaminants [22] in biological matrices and to quantify local chemical concentrations [17, 23–25].…”

“…The technique determines the elemental composition of a biological sample; it thus can be applied in analyses using elemental constituents as markers, e.g., for the presence of certain proteins, for disease diagnosis, for the mode and potential of biotransformation of a compound, and/or for occurrence of reactive toxicity [26, 27]. The quantification of elements is usually performed either with matrix-matched calibration [28] or with matrix-similar substances such as gelatin [29] or agarose [13, 30]. …”