Nanoparticles In Complex Matrices Research Articles

Direct evidence for the occurrence of indigenous cadmium-based nanoparticles in paddy soils

Speciation of heavy metal-based nanoparticles (NPs) in paddy soils greatly determines their fate and potential risk towards food safety. However, quantitative understanding of such distinctive species remains challenging, because they are commonly presented at trace levels (e.g., sub parts-per-million) and extremely difficult to be fractionated in soil matrices. Herein, we propose a state-of-art non-destructive strategy for effective extraction and quantification of cadmium (Cd)-NPs – the most widespread heavy metal in paddy soils – by employing single particle inductively coupled plasma mass spectrometry (spICP-MS) and tetrasodium pyrophosphate (TSPP) as the extractant. Acceptable extraction efficiencies (64.7–80.4 %) were obtained for spiked cadmium sulfide nanoparticles (CdS-NPs). We demonstrate the presence of indigenous Cd-NPs in all six Cd-contaminated paddy soils tested, with a number concentration ranging from 2.20 × 108 to 3.18 × 109 particles/g, representing 17.0–50.4 % of the total Cd content. Furthermore, semi-spherical and irregular CdS-NPs were directly observed as an important form of the Cd-NPs in paddy soils, as characterized by transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy (TEM-EDX). This research marks a significant step towards directly observing indigenous Cd-NPs at trace levels in paddy soil, offering a useful tool for quantitative understanding of the biogeochemical cycling of heavy metal-based NPs in complex matrices.

Synthesis and properties of nano-cadmium oxide and its size-dependent responses by barley plant

Present study included technological methods that made it possible to synthesize CdO nanoparticles and carry out their qualitative and quantitative diagnostics, confirming the as-prepared CdO nanoparticles (NPs) were spherical and had a size of 25 nm. Then, under the conditions of the model experiment the effect of CdO in macro and nanosized particles on absorption, transformation, and structural and functional changes occurring in cells and tissues of Hordeum vulgare L. (spring barley) during its ontogenesis was analyzed. Different analytical techniques were used to detect the transformation of CdO forms: Fourier-transform infrared spectroscopy (FTIR), Dynamic light scattering (DLS), X-ray fluorescence analysis (XRF), Scanning electron microscopy (SEM-EDXMA and TEM), X-ray diffraction (XRD), and X-ray absorption fine structure, consists of XANES – X-ray absorption near edge structure, and EXAFS – Extended X-ray absorption fine structure. Quantitative differences in the elemental chemical composition of barley root and leaf samples were observed. The predominant root uptake of Cd was revealed. CdO-NPs were found to penetrate deeply into barley plant tissues, where they accumulated and formed new mineral phases such as Cd5(PO4)3Cl and CdSO4 according to XRD analysis. The molecular-structural state of the local Cd environment in plant samples corresponding to Cd–O and Cd–Cd. The toxicity of CdO-NPs was found to significantly affect the morphology of intracellular structures are the main organelles of photosynthesis therefore, destructive changes in them obviously reduce the level of metabolic processes ensuring the growth of plants. This study is an attempt to show results how it is possible to combine some instrumental techniques to characterize and behavior of NPs in complex matrices of living organisms.

Single particle ICP-MS combined with internal standardization for accurate characterization of polydisperse nanoparticles in complex matrices

Single particle inductively coupled plasma-mass spectrometry (sp-ICP-MS) is becoming a popular tool to analyze nanoparticles.

Single-particle ICP-TOFMS with online microdroplet calibration for the simultaneous quantification of diverse nanoparticles in complex matrices

Online microdroplet calibration is used to determine the mass and particle number concentration of inorganic nanoparticles (NPs) without the use of NP standards. This approach can be applied directly to quantify NPs in environmental matrices.

Tracking the Transformation of Nanoparticulate and Ionic Silver at Environmentally Relevant Concentration Levels by Hollow Fiber Flow Field-Flow Fractionation Coupled to ICPMS.

It is a great challenge to monitor the physical and chemical transformation of nanoparticles at environmentally relevant concentration levels, mainly because the commonly used techniques like dynamic light scattering and transmission electron microscopy are unable to characterize and quantify trace level nanoparticles in complex matrices. Herein, we demonstrate the on-line coupled system of hollow fiber flow field-flow fractionation (HF5), minicolumn concentration, and inductively coupled plasma mass spectrometry (ICPMS) detection as an efficient approach to study the aggregation and chemical transformation of silver nanoparticles (AgNPs) and ionic Ag species in the aqueous environment at ng/mL levels. Taking advantage of the in-line dialysis of HF5, the selective capture of Ag(I) species by the resin in minicolumn, and the high selectivity and sensitivity of ICPMS detection, we recorded the aggregation of 10 ng/mL AgNPs in complex matrices (e.g., NOM, Na+/Ca2+), revealing an interesting tiny AgNPs formation process of photoreduction of trace level Ag(I) that is different from larger AgNPs generated at high concentration of Ag(I) by accurate characterization and respectively identifying and quantifying new thiol-complexed Ag(I) and residual Ag(I) in the intertransformation of Ag(I) and AgNPs in domestic wastewater by simultaneously detecting the S and Ag signals via ICPMS.

Physicochemical and biological interactions between cerium oxide nanoparticles and a 1,8-naphthalimide derivative

Cerium (Ce) oxide nanoparticles (CNPs) have attracted attention due to their high bioactivity and unique redox-chemistry. The oxygen vacancies at the surface of the nanoparticle explain the autocatalytic properties of CNPs in which the Ce3+ atoms occupy the center of the oxygen vacancies surrounded by Ce4+ atoms. Until now, CNPs have been associated with organic molecules at the synthesis stage to extend their applications or improve their stability. However, there is a lack of information regarding the post-synthesis interaction of CNPs and organic molecules that could enhance or induce new properties. Due to their unique optical properties and their many uses in different areas such as supramolecular chemistry or biomedicine, we have chosen a derivative from the family of naphthalimides (the 4-amino-1,8-naphthalimide-N-substituted; ANN) to study the interaction with different CNPs (CNP1-4) and their joint bioactivity compared to that of the same compounds alone. ANN-CNP complexes were formed as revealed by spectroscopic studies, but, the interaction was markedly different depending on the physicochemical properties of CNPs and their surface content of Ce3+ sites. The ANN adsorption on all CNPs involved the amino group in the naphthalene moiety as shown by NMR spectroscopy, while the pyrrolidine ring was mainly involved in the specific interaction between ANN and CNP1. The biological effect of each CNP and ANN individually and forming complexes was assessed using a bioluminescent model bacterium. The results showed that ANN and CNP with the higher content of surface Ce3+ (CNP1) when combined acted additively towards the used model organism. In the opposite, ANN-CNP2, ANN-CNP3 and ANN-CNP4 complexes were antagonistic when the nanoparticles dominated the mixture. The results of this study contribute to expand the knowledge of the interaction between nanoparticles and organic molecules which may be useful for understanding the behavior of nanoparticles in complex matrices.

Characterizing the Nano-Bio Interface Using Microscopic Techniques: Imaging the Cell System is Just as Important as Imaging the Nanoparticle System.

The rapid growth of nanotechnology and its industries has elevated the need to understand the risks associated with handling, using, and disposing of nanomaterials. These risks can be assessed through exposure measurement and hazard identification. One of the common challenges associated with quantifying nanomaterials in products, waste, humans, or the environment is the lack of tools available to measure concentration. The ability of refined tools and techniques to qualitatively detect nanoparticles in complex matrices has been demonstrated. For biological and ecological tests systems, dose can be represented as initial concentration in the applied matrix, concentration administered during the route of exposure, concentration at the target organ, and intake concentration at the cellular level. Each of these concentration measurements requires different sets of tools to perform accurate analyses. Advances in microscopy techniques provide new opportunities for reporting observations occurring at the interaction of a nanoparticle with a biomolecular entity of similar size within a biological test(s) system. This protocol outlines the steps to image nanomaterials within cell-based systems. © 2017 by John Wiley & Sons, Inc.

Single-particle multi-element fingerprinting (spMEF) using inductively-coupled plasma time-of-flight mass spectrometry (ICP-TOFMS) to identify engineered nanoparticles against the elevated natural background in soils

This novel single-particle multi-element fingerprinting (spMEF) method makes it possible to discriminate engineered and natural nanoparticles in complex matrices.

Separation and quantification of metallic nanoparticles using cloud point extraction and spectrometric methods: a brief review of latest applications

Reliable quantification of metallic nanoparticles in complex matrices is a difficult task.

Characterization of silver nanoparticles-alginate complexes by combined size separation and size measurement techniques.

The detection and quantification of nanoparticles is a complex issue due to the need to combine "classical" identification and quantification of the constituent material, with the accurate determination of the size of submicrometer objects, usually well below the optical diffraction limit. In this work, the authors show that one of the most used analytical methods for silver nanoparticles, asymmetric flow field-flow fractionation, can be strongly influenced by the presence of dissolved organic matter (such as alginate) and lead to potentially misleading results. The authors explain the anomalies in the separation process and show a very general way forward based on the combination of size separation and size measurement techniques. This combination of techniques results in more robust AF4-based methods for the sizing of silver nanoparticles in environmental conditions and could be generally applied to the sizing of nanoparticles in complex matrices.

Colorimetric detection of catalytic reactivity of nanoparticles in complex matrices.

There is a need for new methodologies to quickly assess the presence and reactivity of nanoparticles (NPs) in commercial, environmental, and biological samples since current detection techniques require expensive and complex analytical instrumentation. Here, we investigate a simple and portable colorimetric detection assay that assesses the surface reactivity of NPs, which can be used to detect the presence of NPs, in complex matrices (e.g., environmental waters, serum, urine, and in dissolved organic matter) at as low as part per billion (ppb) or ng/mL concentration levels. Surface redox reactivity is a key emerging property related to potential toxicity of NPs with living cells, and is used in our assays as a key surrogate for the presence of NPs and a first tier analytical strategy toward assessing NP exposures. We detect a wide range of metal (e.g., Ag and Au) and oxide (e.g., CeO2, SiO2, VO2) NPs with a diameter range of 5 to 400 nm and multiple capping agents (tannic acid (TA), polyvinylpyrrolidone (PVP), branched polyethylenimine (BPEI), polyethylene glycol (PEG)). This method is sufficiently sensitive (ppb levels) to measure concentrations typically used in toxicological studies, and uses inexpensive, commercially available reagents.

Simple functionalization strategies for enhancing nanoparticle separation and recovery with asymmetric flow field flow fractionation.

Due to the increasing use of engineered nanomaterials in consumer products, regulatory agencies and other research organizations have determined that the development of robust, reliable, and accurate methodologies to characterize nanoparticles in complex matrices is a top priority. Of particular interest are methods that can separate and determine the size of nanomaterials in samples that contain polydisperse and/or multimodal nanoparticle populations. Asymmetric-flow field flow fractionation (AF4) has shown promise for the separation of nanoparticles with wide size range distributions; however, low analyte recoveries and decreased membrane lifetimes, due to membrane fouling, have limited its application. Herein, we report straightforward strategies to minimize membrane fouling and improve nanoparticle recovery by functionalizing the surface of the nanoparticles, as well as that of the AF4 membranes. Gold nanoparticles (AuNP) were stabilized through functionalization with a phosphine molecule, whereas the surface of the membranes was coated with a negatively charged polystyrenesulfonate polymer. Improved nanoparticle separation, recoveries of 99.1 (±0.5) %, and a detection limit of 6 μg/kg were demonstrated by analyzing AuNP reference materials of different sizes (e.g., 10, 30, and 60 nm), obtained from the National Institute of Standards and Technology (NIST). Furthermore, the stability of the polymer coating and its specificity toward minimizing membrane fouling were demonstrated.

First steps towards a generic sample preparation scheme for inorganic engineered nanoparticles in a complex matrix for detection, characterization, and quantification by asymmetric flow-field flow fractionation coupled to multi-angle light scattering and ICP-MS

Engineering nanoparticles in complex matrices.

Single particle ICP-MS combined with a data evaluation tool as a routine technique for the analysis of nanoparticles in complex matrices

spICP-MS measurement with a powerful data evaluation tool is presented as a fast, cost efficient and easy to use screening tool for metal and metal oxide NPs in complex matrices.

Current and Emerging Technologies for the Characterization of Nanomaterials

This paper provides a survey of conventional and emerging techniques that are available for characterizing engineered nanoparticles in complex matrices. Techniques that were considered include microscopy (TEM, SEM, HRTEM, DLS, SNOM), chromatography (HDC, FFF), mass spectroscopy (ICP-MS, SEC-ICP/MS, MALDI, FFF-ICP-MS), sp-ICP-MS, and electrochemical techniques. A case study is presented from the authors’ laboratories for the design of a portable nanoparticle analyzer based on tangential flow filtration and electrochemical detection (EC-TFF). EC-TFF is equipped with poly(amic) acid membrane filter electrodes (PMFE) arrays that perform multiple functions to capture, isolate, and detect (CID) engineered nanoparticles. The application of EC-TFF is presented for the characterization of engineered nanosilver in real-world samples. A size-dependent isolation of AgNPs was achieved at varying particle sizes with over 98.5% removal efficiency. PEC-TFF AA showed an excellent performance not only for isolation at subnanometer-sized ranges but also as a platform for detection of engineered nanoparticles at low ppb levels.

State of the art in human risk assessment of silver compounds in consumer products: a conference report on silver and nanosilver held at the BfR in 2012

In light of the broad spectrum of products containing nanosilver, the harmfulness of nanosilver to human health and the environment was intensively discussed at a conference held in February 2012 at the BfR. The conference agenda covered the aspects of analytics of nanosilver materials, human exposure and toxicology as well as effects on microorganisms and the environment. The discussion recovered major gaps related to commonly agreed guidelines for sample preparation and central analytical techniques. In particular, the characterization of the nanoparticles in complex matrices was regarded as a challenge which might become a pitfall for further innovation and application. Historical and anecdotal records of colloidal silver have been sometimes taken as empirical proof for the general low toxicity of nanosilver. Yet as reported herein, a growing number of animal studies following modern performance standards of toxicity testing have been carried out recently revealing well-characterized adverse effects on different routes of exposure in addition to argyria. Furthermore, recent approaches in exposure assessment were reported. However, consumer exposure scenarios are only starting to be developed and reliable exposure data are still rare. It was further widely agreed on the workshop that the use of silver may lead to the selection of silver resistant bacteria. With respect to its environmental behavior, it was suggested that nanosilver released to wastewater may have negligible ecotoxicological effects. Finally, the presentations and discussion on risk assessment and regulation of nanosilver applications gave insights into different approaches of risk assessment of nanomaterials to be performed under the various regulatory frameworks.