Plant uptake and accumulation of nanoparticles (NPs) represent an important pathway for potential human expose to NPs. Consequently, it is imperative to understand the uptake of accumulation of NPs in plant tissues and their unique physical and chemical properties within plant tissues. Current technologies are limited in revealing the unique characteristics of NPs after they enter plant tissues. An enzymatic digestion method, followed by single-particle inductively coupled plasma-mass spectrometry (SP-ICP-MS) analysis, was developed for simultaneous determination of gold NP (AuNP) size, size distribution, particle concentration, and dissolved Au concentration in tomato plant tissues. The experimental results showed that Macerozyme R-10 enzyme was capable of extracting AuNPs from tomato plants without causing dissolution or aggregation of AuNPs. The detection limit for quantification of AuNP size was 20 nm, and the AuNP particle concentration detection limit was 1000 NPs/mL. The particle concentration recoveries of spiked AuNPs were high (79-96%) in quality control samples. The developed SP-ICP-MS method was able to accurately measure AuNP size, size distribution, and particle concentration in the plant matrix. The dosing study indicated that tomato can uptake AuNPs as intact particles without alternating the AuNP properties.

Effect of dwell time on mean particle size calculation for 250 000 particles per mL of 60 nm Au NPs nebulized at 300 μL min−1.

This article is one of a series of 4 that reports on a task of the NanoRelease Food Additive project of the International Life Science Institute Center for Risk Science Innovation and Application to identify, evaluate, and develop methods that are needed to confidently detect, characterize, and quantify intentionally produced engineered nanomaterials (ENMs) released from food along the alimentary tract. This particular article focuses on the problem of detecting ENMs in food, paying special attention to matrix interferences and how to deal with them. In this review, an in-depth analysis of the literature related to detection of ENMs in complex matrices is presented. The literature review includes discussions of sampling methods, such as centrifugation and ENM extraction. Available analytical methods, as well as emerging methods, are also presented. The article concludes with a summary of findings and an overview of potential knowledge gaps and targets for method development in this area.

Cerium dioxide nanoparticles (CeO2NPs) are among the most broadly used engineered nanoparticles that will be increasingly released into the environment. Thus, understanding their uptake, transportation, and transformation in plants, especially food crops, is critical because it represents a potential pathway for human consumption. One of the primary challenges for the endeavor is the inadequacy of current analytical methodologies to characterize and quantify the nanomaterial in complex biological samples at environmentally relevant concentrations. Herein, a method was developed using single particle-inductively coupled plasma-mass spectrometry (SP-ICP-MS) technology to simultaneously detect the size and size distribution of particulate Ce, particle concentration, and dissolved cerium in the shoots of four plant species including cucumber, tomato, soybean, and pumpkin. An enzymatic digestion method with Macerozyme R-10 enzyme previously used for gold nanoparticle extraction from the tomato plant was adapted successfully for CeO2NP extraction from all four plant species. This study is the first to report and demonstrate the presence of dissolved cerium in plant seedling shoots exposed to CeO2NPs hydroponically. The extent of plant uptake and accumulation appears to be dependent on the plant species, requiring further systematic investigation of the mechanisms.

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